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  • HPH380: What is Passivhaus Plus? – with Heather Johnson

    HPH380: What is Passivhaus Plus? – with Heather Johnson

    Heather Johnson from AD Practice explains what Passivhaus Plus is, how it differs from Passivhaus Classic accreditation and what benefits achieving the standard will afford. She also reveals why most of her clients target ‘Plus’ and outlines the steps to achieve this on a project.

    Interview with Heather Johnson

    Heather Johnson has worked in architecture since the age of 16, starting with a summer job as a CAD assistant. She studied architecture for four years at the University of Bath, with placements and work in Suffolk, where she learnt about barn conversions and rural issues. She then did her Part 2 at the Centre for Alternative Technology as her focus shifted to sustainability. A three-month temporary role at AD Practice back in Wheathampstead, where she grew up, turned into seven years and is where she still works today. Heather is now a Passivhaus Designer and has worked on numerous Passivhaus Plus and EnerPHit Plus projects over the years.

    The performance criteria for Passivhaus ‘Classic’ must be met for ‘Plus’ and ‘Premium’ as well

    Most people have heard of the Passivhaus standard, also known as ‘Classic’ but perhaps less well known are the other certifications ‘Plus’ and ‘Premium’. Before looking at the differences between them, these additional classes must meet the same stringent performance criteria laid out in ‘Classic’. For example the airtightness targets, energy demand, overheating risk and so on.

    In this episode we’re going to focus on Passivhaus Plus and find out about Heather’s own project, a barn conversion, which is aiming for the EnerPHit Plus standard.

    Passivhaus Plus sets a target for on-site renewable generation

    Passivhaus Plus brings renewable energy generation into the certification process, setting a target per metre square of treated floor area (renewable energy generation ≥ 60 kWh/m².a).

    It is a step towards self sufficiency and energy security, and a ‘Plus’ project must cover the home energy usage needs over the course of a year. This does not mean it is off-grid, but that the generation exceeds what gets consumed over a year. So there is likely to more generation at certain times of year according to which renewable is being used.

    Solar PV is the most commonly used on Passivhaus Plus projects

    In the UK, more often than not, solar PV will be chosen as the renewable energy source. The main reason is that most houses are in our towns and cities, where space is a premium and roof space is generally available. The technology has also advanced a great deal over the years. It’s cheaper, more effective and can be integrated seemlessly.

    However, any renewable could be used on a Passivhaus Plus project. For example, if you are beside a watercourse then a water turbine might be appropriate.

    Passivhaus Plus encourages a compact building form

    When it comes to solar PV some key considerations are the roof pitch, orientation and surface area of the roof. If renewable energy generation was the starting point for the design of the house, it might lead us to build a bungalow with lots of roof space. However the surface area to volume ratio would not be good, and therefore we may not reach the other Passivhaus targets.

    “The take home point is you still want to make the building as efficient as possible and then add on the generation.”

    The Primary Energy Renewable factors relect the whole picture

    There’s another characteristic the building must meet.

    Primary Energy Renewable (PER) demand* ≤ 45 kWh/m².a

    According to Passipedia: Renewable primary energy (PER) is the unit of energy generated from renewable resources. PER-factors reflect the primary renewable resources needed to cover the final energy demand of a building, including distribution and storage losses. In the case of a PER-factor of 1.5, a surplus of 50% renewable primary energy is needed to be able to meet the final energy demand at the building. The higher the PER-factor, the higher the required resources and therefore the more important the implementation of efficiency measures in order to avoid compensation from non-renewable sources.

    Permission is required to export electricity to the grid

    Although smaller scale renewable schemes (typically under 3.68kW per phase) do not require permission to export to the grid, a Passivhaus Plus project will need approval from the District Network Operator. Depending on the infrastructure of the local area there may be limitations.

    However, Heather says that she has never had a project turned down, but it is always a possibility.

    Additional constraints make achieving EnerPHit Plus more challenging

    Retrofits can also achieve the ‘Plus’ certification. The main difference between a new build and a retrofit is the additional opportunities that building from scratch affords.

    With an existing building the orientation is set and without significant work so is the roof space, orientation and pitch.

    Amongst Heather’s design process she is keen not to break up the long parts of the roof, which are best for energy generation, with rooflights or other roof forms.

    There may be other challenges, as well, such as planning restrictions if a property is in a conservation area. This was the case with Harpenden EnerPHit Plus but a whole roof pitch of solar PV was eventually accepted.

    Heather makes a comparison between the Harpenden EnerPHit Plus which spent £95 on electricity for a year, and her office which typically spends around £200 a month, so it is a huge saving!

    On another retrofit project it made sense to rotate the roof by 90 degrees. This not only increased solar generation but created a mezzanine with a view of the surrounding countryside, which the client didn’t have before.

    Solar PV has come a long way and can now look fantastic

    There can be a double win from maximising generation because a whole roof pitch of solar PV can become the roof finish as well, saving money on tiles, etc.

    Heather often uses the GB-Sol, Infinity system, which is completely seamless.

    On a Passivhaus Plus project in Wheathampstead there is a more conventional in-roof solar array, which does not cover the whole roof. The solar panels are inset so they’re flush with the concrete tiles but it’s not a seamless finish. Interestingly, the clients wished they had put more solar PV on the roof.

    Heather say the cost of solar PV has come down dramatically from when they were first being installed. Unfortunately, the feed-in tariffs for exporting have also gone down, but there is still a much shorter payback period.

    There are also schemes around, such as Solar Together in Hertfordshire, that give discounts for solar installations. It’s becoming a much more attractive offering, especially with more people opting for electric cars.

    Solar PV does not just have to be on south-facing roofs

    South facing roofs tend to work best for solar PV but that doesn’t mean it ends there. When Heather speaks to the suppliers and specialists, they’re quite keen on southeast and southwest as well. This gives a longer period of time generating power, so can be better for the homeowner and takes pressure off the grid at peak export times. North facing won’t give as much generation, but a mixture of orientations will give more consistent energy generation throughout the day.

    Use as much of the energy generated on site, before exporting

    There’s normally a hierarchy of uses for the energy that is generated on site.

    For example, it may be running a heat pump, topping up the hot water, charging a battery or an electric car. So exporting to the grid would be the last option.

    Different suppliers also pay different rates for exported electricity and these rates will probably vary during the day. So if you have a home battery you can maximise your return by importing and exporting at specific times. For example, if you need to draw from the grid to charge your battery it makes sense to do it overnight when the tariffs are low.

    Heather even wants to make her ‘long, thin barn’ an EnerPHit Plus

    Heather and her husband fell in love with a barn in rural Hertfordshire, which was ripe for modernising. It’s a long thin brick building that is not really conducive to a Passivhaus project, but this has not deterred them!

    The first air test achieved 0.7 air changes per hour at 50 Pascals so it’s well under what’s needed for the EnerPHit standard.

    As they are targeting EnerPHit Plus, the large roof area makes it easy to achieve the required generation and they are looking to install around 50 solar PV panels.

    Heather’s barn is being converted in two phases

    Heather is converting the building in two phases. As it is long and thin (around 25 metres) the barn will have two MVHR units (to limit the length of duct runs). Phase one is the old traditional barn, the taller area, with a side utility room and shower room that’s run off one system. They plan to put up a temporary wall up at the end, so they can live in that part of the house, studio style, whilst they carry on fitting out the rest of the house.

    A new timber structure is being built within the old barn

    Heather is taking a similar approach to this barn conversion as they did at Stirley Farm. They are building a timber box within the old brick structure.

    So there’s an insulated slab (the Isoquick system) and I-stud walls which are filled with cellulose insulation. The new extension will be finished with timber cladding, whilst the existing barn will be the existing brick, retaining the historic fabric.

    The design does not add any loads to the original building as that would have required underpinning. The existing timber trusses have been retained and now function as tie beams within the new timber frame structure. Heather explains that because the building is essentially a long tube, it needs the beams to stop it just squishing and falling flat.

    Dealing with ventilation and moisture across the old and new structures

    Heather outlines that where they’ve built against the brick wall, they have a nominal 50 to 100mm cavity, which is much wider in places because the brick walls are not straight. With the new timber clad structure there is a rain screen system, which is battened and counter battened out before the cladding is put on. The timber frame is also wrapped in a membrane before the cladding goes on, so any moisture would hit the membrane and trickle out the bottom, as with many similar systems.

    The bigger risk with phasing the work is that they don’t ventilate the uninhabited internal spaces correctly. As it is airtight and insulated, they need to make sure air is circulating by using fans and opening windows. Otherwise condensation could occur which would eventually lead to mould.

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  • HPH366: Could a home energy transformation pay for itself?

    HPH366: Could a home energy transformation pay for itself?

    Howard Johns, founder of One Zero, outlines their home energy transformation service which includes topping up insulation and adding solar PV, battery storage and a heat pump.

    Interview with Howard Johns

    Howard shares his extensive knowledge of renewable energy, and how he has moved from managing a large portfolio of solar and wind farms to enabling people to generate their own energy. Over the years it has become apparent to Howard that the real sticking point with the large scale projects is the National Grid, which is currently struggling to take new connections. His new company One Zero energy, is focusing on how we retrofit homes in an efficient and light way that can enable them to become part of a new, flexible, distributed grid.

    The UK grid is no longer fit for purpose

    Electricity companies began as regional entities, with one power station supplying each local area, which worked until there was a problem with that station or too much demand. With no back up in the system, some areas of supply would have to be shut down to enable other areas to keep going. Our current grid system was a national project to join all these power stations together with transmission lines so that it had more inherent flexibility. But essentially, it was built as a one-way system, with power being generated in a small number of locations and then flowing to a large number of supply locations.

    With the advent of renewables, particularly wind and solar, distributed generation emerged. So generation is happening in all sorts of locations and Howard explains how we are rewiring the grid backwards to allow this, which has caused a lot of issues. In fact, in many areas it is just not possible to connect any more large-scale renewable generation because the infrastructure cannot take it. If we can’t do that and need energy transformation now to tackle climate change we need to look at other options.

    The current energy system is extremely inefficient

    Howard explains that for every 100 units of gas used only 40 of those turn into useful units of electricity. During transmission to our homes another 10% is lost and then we might lose more through inefficient appliances. The usable energy you’re getting in your home from that primary energy is around 30%. So if you start to generate energy where you need it you can massively reduce the wastage.

    With heat pumps we can be getting 400% more energy out of it than we put in, compared to maybe 90% efficiency with a gas boiler. It is similar with transport, a standard fossil fuel car is about 30% efficient, whereas you can double or treble the efficiency for an electric vehicle. In other words the new electric based technologies that are emerging are the future.

    A resilient energy system has more back-up options

    Howard outlines how we already have at least five interconnectors into this country to build resilience in the system. A European wide grid allows excess energy, say from Denmark, to be supplied to other European countries.

    Behind the scenes at the National Grid (NESO) people are looking at live demand, and turning on things like peaker plants and gas plants, and using batteries in some cases to meet that demand.

    A resilient system must get past intermittency

    As the amount of renewable generation increases, there’s a new challenge – intermittency. So there will be a correlation between the weather conditions and how much is generated. For example, on a sunny day we might generate 20% of our power from solar, but there will be nothing at night. At times we will get really high levels of grid energy powered by the wind, but on a still day, we may get very little. This is one of the key features of the new system and it is causing problems.

    Better storage capacity will help solve the problem

    As the cost of energy continually changes if we have the access to battery storage then we can benefit. So it makes sense to use energy at key moments, when it’s abundant and cheap, and avoid using it at six o’clock in the evening when the demand is highest and it’s expensive.

    It’s always preferable to use energy as it’s being generated

    Howard tells us that it is preferable to use energy as it’s being generated because there will always be losses associated with storage. With batteries you lose around 10% of the energy you put in, just in charging and discharging. However if you haven’t got demand for that power, it’s still a sensible thing to do.

    Part of One Zero’s strategy is to install a solar PV array in combination with battery storage. This would mean that for eight months of the year you could be virtually self-sufficient for power. With a decent control system you can effectively run your battery as a micro power station profiting from arbitrage and engaging in the flexibility markets.

    Import and export to the grid when it makes financial sense

    With many big batteries being built across the UK there may be times when power is cheap or even free! So, in addition to your own generation, in these moments it may make financial sense to import from the grid to charge your home battery or discharge power back to the grid.

    Innovative companies, like Octopus and Ovo, already have flexible tariffs that will give you different power prices at different times of day.

    Howard thinks the next step would be managed services that take into account wholesale prices, which change every half an hour. Again these have periods where energy is very cheap or even negative, and other times when it’s expensive. With an agile tariff you could see prices change from -2p to 50p a kilowatt hour over a 24-hour period. Software is needed for this management, however, and this is a service that One Zero are working on.

    “Generating and storing power at your home is probably the most cost effective way of getting power right now. Not many people realise that.”

    Heat pumps will work without a deep retrofit

    Using heat pumps is another part of the One Zero energy transformation strategy. People may be under the impression that a deep retrofit – improving the thermal performance, and the health and comfort of the building – is required to make these systems work but that is not the case. So at One Zero they suggest a light touch retrofit, topping up insulation levels and doing the easy wins.

    Howard points out that putting a heat pump on a really leaky house is going to be inefficient, but heating it with a gas boiler is also inefficient, so on one level there’s no difference. At the same time, if you use a heat pump, you may also knock four or five tons off your CO2 emissions every year.

    However, it still makes sense to do as much as you can to reduce heat loss. When One Zero assess a property, they’ll make recommendations around deeper measures, which could be done first or incrementally over the following years to improve efficiency.

    Considering payback has been a big part of this approach

    One Zero are looking at measures that could start to pay back in 5 years rather than 40 years or more for deeper retrofits. Howard believes there are millions of homes that need to be improved in the next decade or two, so it’s important that this really appeals to people and offers a clear win. By starting with solar PV and a battery people can achieve a cash flow that they then might reinvest in the next steps. One Zero are also looking at finance packages so you don’t need all the capital upfront to get started on this home energy transformation.

    One Zero plan is for people not looking to do a deep retrofit

    Howard explains that One Zero is aiming to reach people that will not undertake a deep retrofit of their property, either for financial reasons or lack of engagement with this approach. Their approach is to provide a top up for cavity wall and loft insulation and then solar PV, a battery and a heat pump all for around £21,000. You could have a home energy transformation that would drop your bills by around 50-60% and your carbon emissions by 70%, all delivered within two weeks with minimum disruption. They think this is achievable for homes built after the 1930s, which already have some cavity wall insulation, double glazing and some loft insulation.

    What is a deep retrofit? Check out the Kinver story in The Hub.

    Every technology has an impact, but this should be weighed up against the alternative

    Howard has put a great deal of research into the One Zero home energy transformation package. He believes that if we reached 100% renewable generation our rates of extraction of raw materials from the earth would drop to about a 30th of current levels. The backdrop is that we live in a highly extractive society, where 40% of global shipping relates to fossil fuels.

    Everything we do has an impact, so with solar panels, there’s polysilicon production and issues around the supply chain, particularly with indentured slavery in some provinces of China, which can be hard to get around. This is also the case with many other products we are using. A solar panel can liberate the energy that went into making it within nine months of it being in use and the panels then have a 25-year warranty and possibly up to a 40-year lifespan. Most modern solar panels don’t contain any rare earths, they are just copper, an aluminium frame, silver for the conductors and glass. Effectively, polysilicon is a form of refined sand, and so all the parts are recyclable. There isn’t a huge recycling market yet, because most of the panels that have been installed are still in use.

    People are also concerned about the huge amount of lithium being produced for home and car batteries. Howard explains that there are two ways in which lithium is produced. One is from mining, generally in Australia, whilst in the rest of the world lithium production is from liquid deposits. These exist as brines under the surface of the earth that can be extracted through a bore hole. The lithium is then taken out and the remaining liquid is pumped back down. So there is an impact but it should be smaller than for mining. Also lithium is a recyclable material, which is abundant in the UK.

    Many manufacturers are now redesigning batteries so that they don’t contain cobalt, so as we move forward there should be fewer issues around rare minerals.

    Heat pumps are generally made from copper and steel, both of which are abundant in a recycled form across the world. There’s a refrigerant involved, with two possible types, one of which has a lot less global warming potential.

    All of these technologies will have a lower impact when compared to the extraction of fossil fuels and the resultant CO2 emissions from using them.

    A repowered house – taken off the gas network

    Your home can help you reduce your carbon footprint

    For a typical dwelling One Zero’s home energy transformation could save between 3-6 tons of carbon over the course of a year, which is equivalent to 20 or 30 flights to Spain. For Howard this is incredibly impactful.

    Your electric car battery could support your home energy use

    It’s still early days but trials in vehicle to grid energy transfer could support our home energy use. An electric car could have a 30-100 kilowatt battery in it, while your home battery may only be 10 kilowatts, so if you could plug your car into your home and use your car battery to support your home that would be valuable.

    It’s also a lot of lithium sitting around that could be used more effectively. Nissan is currently the only car manufacturer that allows this but that could change. The challenge is that most car manufacturers want their batteries used solely for powering their cars and consequently you will invalidate the warranty if it is used for other purposes.

    However, these batteries have huge potential to increase storage capacity and help with the intermittency challenge in power generation. And Howard suggests that even accessing 10% of these batteries could have a meaningful impact.

    One Zero has a community focus to support people on their renewable energy journey

    People can be cautious, so One Zero is working to give people the confidence to act and then supporting them to share their experience with others. Currently they are geographically focused, working in communities where they can sign up more than one house at a time, maybe 5-10 houses across two or three streets. So they are reaching out to people who may not have thought they could be part of this journey into renewables, to help them change the way they think about it.

    One Zero is operating in Sussex at the moment and has plans to launch in more areas over the course of the coming year. The next steps could be looking at managing a micro grid behind a distribution transformer that serves a street, so there would be enough generation and storage to provide the community with power for a large part of the year.  

    “It’s turning it from, that me and my castle thing, into us and our street.”

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  • HPH324 : Why robust planning is vital for a home retrofit in stages – with Alan Budden

    HPH324 : Why robust planning is vital for a home retrofit in stages – with Alan Budden

    Alan Budden explains how a phased retrofit might work and what preparation is required. He also shares how he’s retrofitted his own home, which includes trialling an innovative roof solution.

    The house (after the retrofit)

    Interview with Alan Budden

    Alan has been on the podcast before. Last time he explained how simple design decisions can impact on energy performance and cost.

    In this session he reflects on his own retrofit which is getting towards the final stage.

    Alan’s practice Eco Design Consultants is well versed with deep retrofit and were the architecture firm leading the Kinver project.

    Get access to our in-depth video case study of the Kinver retrofit in The Hub

    If you have the funds, tackle a retrofit in one go

    Nobody ‘chooses’ to do a staged retrofit because it’s a better option to do all the work in one hit.

    Not only will it be cheaper overall (for example tradespeople might have to make a few more visits during a phased retrofit) but the disruption will also be minimised.

    And from a planning perspective it will be simpler too.

    There’s lots of junctions you have to consider in terms of how it’s going to be weathered and work during that stage, as it could be six months, it could be 10 years between stages. That’s one of the issues. So you end up detailing things, then for the final construction detailing it back.

    Retrofitting in stages is a way to progress with the money you have today

    Recently Alan has noticed a lot more enquiries from young families who are keen to upgrade their homes.

    Unfortunately they lack the funds for a comprehensive retrofit so Eco Design Consultants recommend tackling it in stages.

    The most important aspect is to have a whole house plan before you start.

    A staged retrofit could allow you to stay put during building work

    Depending on the size of the house one benefit of a phased approach is that you might be able to move around the house while the work is being done, thus save money on moving out and renting accommodation.

    Retrofit at an appropriate stage in the maintenance cycle

    All houses require maintenance and upgrading so there will naturally come a point where you’ll be spending money on your home anyway.

    The house still had single-glazed windows

    The single-glazed windows were not fit for purpose and had been something Alan had wanted to change ever since he bought the property. While he could have upgraded to double-glazing he bided his time so that it would be a switch straight to triple-glazing. His cladding was also tired and needed replacing so doing all these things together can contribute to the project costs.

    The front of the house (before the retrofit)
    The back of the house (before the retrofit)

    Think of a deep retrofit as creating a house for life

    A deep retrofit is significant work so it’s unlikely that you’d just want to sell the house straightaway afterwards. So you should be trying to make the house work for you now and into the future.

    Think carefully about how you want to live in the house. Could you also add a bit of value (by increasing floor area, if needed)?

    Can the house shape be simplified?

    Alan wanted to do the design work himself

    Despite having an architecture practice at his disposal, Alan thought the ethical approach was to do the design work and modelling himself. Consequently progress was slow, being confined to evenings and weekends.

    Modelling the house in PHPP is a key step

    Alan says that after deciding how you want to live in the house and optimising the layout, the next step is to begin modelling it in the Passive House Planning Package. Setting an energy target for the project, such as the Passivhaus retrofit standard EnerPHit, helps inform decisions about insulation, windows, etc.

    The shape (or form factor) of the house was improved

    Where the first floor was slightly smaller than the ground floor Alan decided to square up the building. This increased the floor area, allowing for a new dressing room and increasing the size of the en suite. but also simplified the shape of the building.

    Alan’s knowledge meant he could optimise his approach

    When selecting materials Alan was always looking at a balance between cost, performance and embodied carbon.

    I looked at some interesting things with the external wall upstairs. Timber frame work projects off the wall with GRP brackets with just ordinary cavity wall insulation inside. So I’ve looked at the DriTherm 32, the DriTherm 36 and a couple of others, so it’s different types of mineral wool. And as it was less… the thermal conductivity was worse, the density was less, and the embodied carbon was less and the cost was less. So trying to optimise how thick the insulation was, and which ones I used was quite interesting. And depending on what sort of brackets I could get as well for the timber frame. So it was quite a complex lot of options.

    Think how you can stretch funds

    Alan planned to do parts of the work himself to save money and therefore, hopefully, take the project further.

    He was also planning to test a new roof system which would be manufactured off site and placed onto the existing trusses, but it had a few teething problems. Knowing there would be a delay in the programme there was nothing to be gained by hiring builders to get through the work quickly.

    The builder was happy to step in as required

    Alan describes how he and his family put on the membrane (from the scaffolding). The builders then came and put the brackets on and the timber framework. And then it was back to Alan and family to fill it with insulation. And so on.

    After taking the roof off the utility room and building upwards, they stripped the tiles off the rest of the building and made a few adjustments in preparation for the new roof cassettes.

    A stick-on airtightness membrane, Siga Majpell 500, was installed.

    A multi-purpose roof was manufactured off site

    Alan has always been interested in how retrofit might be tackled at scale and as such he’s been part of a group developing an innovative roof panel system.

    With funding from Innovate UK the project has progressed and he has become the guinea pig for the first full installation.

    The idea was to develop a structural roof panel that includes PV and solar thermal, using that to heat the house.

    Off-site manufacture comes with benefits

    Using a crane the panels were lifted into place in just one day.

    This is a big health and safety benefit because it reduces the amount of time that people are working at height.

    Alan comments that making the roof panels have more than one purpose should bring about some economies of scale.

    Unfortunately some of the technology underneath the panels that was being used to cool them didn’t work as planned, so they are looking at an alternative and hoping to lift off two of the panels off and replace them with new ones. Then they can get them plumbed in and see how much energy they are reaping from the roof and how that’s helping to improve the performance of the PV.

    Project delays meant Alan was without a roof for 6 months!

    With development delays and then the pandemic Alan was caught in a tricky situation. He had taken off his old roof, added a membrane and then discovered the roof panels were not ready!

    The manufacturers of the membrane normally suggest that it can be exposed to the elements for up to a month.

    So Alan had a challenge on his hands, particularly when a big storm came along.

    My roof was left exposed for just over six, including the winter, which is not the best of times, which meant that I was getting condensation forming on the inside because the insulation was planned to be put on the outside and I had some insulation left in the loft to keep us a little bit warm in the winter. So I was having to mop it down, which shows you really, the amount of water I was taking off was quite considerable. At the worst times, I almost had a bucket full of water. I was at the end of it with my mop! And it does show you how much moisture you’re putting out as a family. And if that’s going to condense somewhere that could cause all sorts of problems. Luckily I could see it, I could deal with it. And now obviously that’s gone away.

    The membrane did survive and seems to be doing its job.

    Get the MVHR online as soon as the house becomes airtight

    In a new build the MVHR might be commissioned towards the end of the process but in a staged retrofit it needs to go on sooner, otherwise moisture and CO₂ will build up.

    The only downside of that is you will probably go through more filters as they get clogged up with the dust and the dirt from both the outside and the inside. Alan has been switching off the unit altogether if there are particularly dirty or dusty jobs going on.

    The insulation will go internally on the ground floor

    Alan wanted to keep some of the brickwork visible externally to match other houses in the estate, which means an internal insulation strategy is required downstairs.

    The windows downstairs will open outwards to maximise insulation on the frames

    All the windows upstairs have been changed because they went within the external insulation so they’re opening inwards. On the ground floor we’re doing internal insulation and those windows can open outward so we can maximise the insulation onto the frames on the insides. So there’s a number of windows downstairs still to be done. I did, we did take a few opportunities to insulate some of the windows on the ground floor, for instance outside our snug and the downstairs toilet because there’s some external cladding there with some vertical battens instead of horizontal just to emphasise… a bit of architecture! And also squeeze in a bit more external insulation.

    There’s added motivation as they near the end of the project

    The final stage of the project will be to insulate internally on the ground floor and replace the windows.

    One of the things that’s happened because of the extended programme is that we’ve been able to keep going. We weren’t necessarily expecting to do the ground floor stuff straightaway but it’s carrying on now! And because upstairs is so much warmer than downstairs, it’s really given us an emphasis to say we need to get this done. You realise the difference. Generally upstairs has been about three to four degrees warmer than downstairs. And that shows all the Passivhaus physics that air moves when there’s three to four degrees difference.

    The builders will come back to replace the windows

    With a house that’s getting warmer as the project progresses, the builders will be coming back to install the windows.

    This will get the changeover done quickly.

    Then it’s back to Alan and family to tackle the internal insulation room by room.

    So we’ll put some studwork up, insulate it, membrane it, re-plasterboard and finish it off. And also on the ground floor, what was going to be phase three that I think might happen at the same time is the floor insulation. The plan is to dig up the screed, put down a phenolic insulation and the board on top.

    A preliminary air test was conducted before the roof went on

    Having installed all the airtightness membranes as a family, Alan wanted an airtightness test before the roof panels went on.

    There were a few reasons for this. While they are always interested in an overall score, it’s more about identifying key leakage hotspots that can then be fixed.

    As with the Kinver project, once the roof is on there will be little hope in fixing leaks in this area.

    That’s why attention to detail is important. The number on this first test was 1.7 air changes per hour at 50 Pascals.

    Biggest risk with retrofit in stages is having to redo work

    Alan says one takeaway from the project is the importance of a well thought out initial plan.

    One thing I’m not enjoying quite so much is in our utility room and kitchen, I had already insulated some of the wall there with 50mm of polystyrene, mainly because at that stage, I was worried about the interstitial condensation. So I was limiting it to what I could do. But because now I’m insulating some on the garage side as well, I can increase the thickness of insulation internally. So I’m having to take out some insulation to put different stuff back in, which is a little bit frustrating to be honest. So get the whole plan done, make sure that works, and then do bits towards it, because that way you’re not going to be replacing those bits.

    Find out more

    Visit the website of Eco Design Consultants

    Follow Alan on Twitter

    Transcript

    Transcript-of-House-Planning-Help-podcast-episode-324-Alan-Budden

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  • HPH321 : How do you make an existing home energy efficient? – with Paul Ciniglio

    HPH321 : How do you make an existing home energy efficient? – with Paul Ciniglio

    With price hikes being caused by the volatile energy sector, Paul Ciniglio from the National Energy Foundation explains what we can be doing to our homes to reduce our energy consumption and be better protected from rising bills.

    Interview with Paul Ciniglio

    Paul Ciniglio is refurbishment lead at the National Energy Foundation, where he spends much of his time being involved with their SuperHomes network. With a background in building surveying, he has over 30 years experience of working in the built environment sector, with a particular focus on sustainable development.

    Renewable energy plays a key part in the UK energy mix

    On some days England is able to produce over half its electricity needs from offshore wind turbines. As renewables are intermittent, however, an energy mix is necessary to keep the lights on. At a domestic level we could be making even more of a contribution with solar PV panels and heat pumps.

    Energy bill rebates would be better spent on improving energy efficiency

    Paul says that the UK government’s plans to issue rebates to households for their energy bills isn’t sustainable in the long term. The only way to bring our bills down to reasonable levels is to use that same money to improve the energy efficiency of our homes and cut out the waste. In order for us to achieve net zero carbon we are going to need to aspire to Passivhaus type approaches and super-insulating homes.

    NEF is an independent charity

    A common problem for people wanting to undertake a home retrofit is knowing where to start and who to trust. As an independent voice, NEF is able to bring that level of trust and support to those embarking on a retrofit.

    Start with a whole house retrofit plan

    NEF can arrange a whole house retrofit plan and this is carried out in accordance with the British Standard BS40104. It entails a survey of your property by a retrofit coordinator, who will then produce an options appraisal as to everything you could do to improve the energy efficiency of your home. It will show the benefits, so the predicted running costs and reduction in household emissions, as well as the estimated cost savings for each retrofit measure.

    There are also risks involved in taking on a retrofit project but these will be flagged up in the retrofit plan at the start, so they can be managed.

    By looking at the whole house view, it is possible to make decisions on what can be done now and what can be done in the future.

    Fabric performance should be the first consideration

    When using a whole house holistic view there is an energy design hierarchy, and the place to start is with the fabric performance of the home.

    • Cut out the heat losses through the fabric of the building, so the doors, windows, insulation in the roof, walls and floors
    • If making the house very airtight, it’s important to factor in the ventilation to prevent damp and poor indoor air quality
    • Look at efficient heating systems – it is likely that we will move towards electrification in the UK which really implies heat pumps
    • Then consider other renewables, such as solar pv to generate clean electricity

    By using a phased plan such as this it means that work is carried out in a logical order, and also that you don’t unwittingly do something that prevents you from adding another measure in your plan later on.

    The risks need to be managed

    This is to ensure that retrofit maintains a good name, is worth doing, and is not going to cause lots of problems.

    With the retrofit plan, each home is assigned a risk pathway, A, B or C (A being the lowest risk, and C perhaps being a historic building).

    A suitable ventilation strategy is absolutely key, as condensation and damp can lead to mould issues. When insulating it’s important to consider moisture, so that it doesn’t get trapped in the fabric of the building and cause bigger problems.

    To get rid of condensation you need three things:

    • insulation
    • heating
    • ventilation

    Without those you are likely to get black mould forming.

    NEF run a best practice retrofit network

    This paid membership is operated by SuperHomes, and gives you access to events and seminars around retrofit issues. You can also then be assigned a retrofit coordinator, who will be someone that is an accredited professional that has achieved a diploma through the Retrofit Academy. These typically are architects, surveyors, and energy managers who have all been through this training.

    The SuperHomes initiative also has a rating scheme, which is a benchmark for retrofit achievement.

    A lot of retrofit can be done with residents in situ

    Sometimes retrofit can be done on a room-by-room basis if it’s carefully managed, but it can be very disruptive. Generally it’s only for the deepest, most challenging projects that residents might need to temporarily move out, although all projects can be carried out more efficiently and easily without the residents living there.

    At House Planning Help, we have followed a deep retrofit in Oxford. Get access to our in-depth video case study in The Hub

    Look out for TrustMark and MCS certification

    Paul explains that there is a massive skills shortage to deliver the amount of retrofit that is needed. Traditional builders are already busy and the energy efficiency market needs to be made more appealing to them so they can upsell skills.

    The government’s TrustMark scheme shows that contractors have been vetted, with the idea being to put the public’s faith in the contracting sector. And if you’re having a heat pump or solar PV installed, then make sure your contractor is accredited to the Microgeneration Certification Scheme (MCS).

    Paul is re-retrofitting his own SuperHome!

    Paul lives in a 1989 mid-terrace cottage, which he retrofitted and became a SuperHome back in 2009. He upgraded the insulation, including putting it in cavity walls where builders were supposed to have put it when it was first built, but hadn’t. He also upgraded the loft insulation, installed an air source heat pump, solar pv, solar thermal, and new windows.

    “My comfort has gone up and I’ve got my own energy security protecting me to a certain extent with these price increases.”

    At the time there were some things he wasn’t able to do, so now he’s taking on a further retrofit, including putting in ground floor insulation. He has also stripped out the solar hot water panels. They worked okay for the first seven years, then only intermittently until eventually being decommissioned. A preferred option now is solar pv that diverts the solar electric into an immersion cylinder to provide the hot water.

    The reason Paul’s solar thermal didn’t work very well he says was because it was too efficient for the size of cylinder he had. By 10am it would be up to temperature and if water wasn’t being drawn off or he was away on holiday, it would stagnate and get really hot, causing damage to the valves.

    The Energy Performance Certificate isn’t up to scratch

    In the wake of the energy crisis, it seems natural that when people are looking for a new home they will be asking how much it costs to run, and this is something the EPC isn’t very good at. NEF is doing some research working with a team of chartered valuation surveyors to carry out property valuations pre and post retrofit. It makes sense that a more energy-efficient home should command a higher price, and Paul says there is emerging evidence that this does seem to be the case.

    Once a SuperHomes retrofit has been completed, they install monitoring equipment for 12 months to gather and evaluate data about household emissions to see how well the property is performing. It’s on that basis that they certify the SuperHome and what level it has achieved. The metrics they use for this are the space heating demands (which are a proxy for the fabric performance and tell you how well insulated your home is), temperature (including checking for overheating in the summer and making sure it doesn’t get too cold in the winter) and humidity and indoor air quality levels.

    Know where you’re going to “get the biggest bang for your buck”

    Having a whole house retrofit plan will mean that you know what improvements are going to make the biggest difference and save you the most amount of money. It’s important to note however that you don’t always get a payback with every retrofit measure, just as you wouldn’t with a new kitchen, car or conservatory.

    Insulation is the most cost-effective way to retrofit, and is simple for lofts and cavity walls. It’s much more of a challenge for the 7 million homes which have solid walls.

    But where funds are limited, Paul explains there are government grants to help private homeowners insulate their homes. There was a local authority delivery grant program administered through regional energy hubs that can help households with incomes of less than £30,000. There is also a new Energy Company Obligation (ECO4) which is another source of funding. Sometimes there are local grants available too.

    Find out more

    Visit the SuperHomes website

    Follow National Energy Foundation on Twitter

    Check out the Tape Notes podcast

    Transcript

    Download a transcript of the interview with Paul Ciniglio

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  • HPH210 : A future-proof contemporary eco home – with Liz and Mike Hill

    HPH210 : A future-proof contemporary eco home – with Liz and Mike Hill

    Liz and Mike Hill explain the decisions behind the design of their contemporary eco home.

     

    Interview with Liz and Mike Hill

    When Liz and Mike decided to downsize from their family home they took the opportunity to divide their existing plot and build on the land.

     

    They selected their architect based on which one helped to develop their brief

    Ultimately their desire was for a sustainable property with functional and well-utilised spaces that worked better for their hobbies and for working from home.

    They produced an architect’s brief outlining what they wanted in terms of size, number of rooms and how they wanted to use the spaces, but soon realised that what they were looking for wasn’t available within their budget.

    Some of the architects they approached took their brief very literally and presented them with an unaffordable option based on what they had asked for. After narrowing it down to two local companies who had experience of Passivhaus, they selected Architype, who had said “we hear what you say, but what about these as alternatives?” That process of dialogue between them led to designs they wouldn’t have expected when they started the process, but which they feel actually work very well for them.

     

    The house is designed to utilise all of the spaces

    It was important for Liz and Mike to future-proof their home with the ability to accommodate elderly relatives if needed. They wanted a ground floor bedroom that could be converted into a bedsit with same level, wheelchair access to a bathroom.

    Liz was keen to buck the trend for totally open-plan living and wanted the kitchen to be separate from the living area so that noise, cooking smells and mess could be kept out of the way.

    They opted for three large bedrooms which they could use as studies or double bedrooms/guest rooms. Although they had space for four or five bedrooms they didn’t want guest rooms sitting empty for the majority of the time.

    From the options that Architype presented them with, they chose a modern-looking design of two inter-locking cubes. The interesting design did mean more consideration about window sizes was needed for it to meet the Passivhaus standard and prevent overheating.

     

    Early collaboration with the architect and builder was beneficial

    Being local, Liz and Mike were aware of  Mike Whitfield Construction, his work and his reputation, so didn’t go out to tender for the job. He was involved even before they went to planning and the ongoing three-way dialogue between themselves, Mike and Architype meant they could work together at this early stage to have confidence they were designing something that could be built effectively. Investing this care and collaboration in the early stages ensured only minor tweaks were required throughout, and the final project came in within budget.

    Groundworks lasted from the summer of 2015 through to the end of that year. The building work started in January 2016, with the house being waterproof within eight weeks, and they moved in during November 2016. It has a timber frame construction using I-beams and Warmcel insulation.

     

    The house combines high-end and budget finishes

    In some case Liz and Mike went with Mike Whitfield’s suggestions, such as oak door with oak latch, which they feel have really added to the aesthetic of their home.

    In other areas they researched finishes themselves and opted for more budget end items. What they were both surprised by was the sheer speed with which they needed to make decisions:

    “And when you’re asked about a decision, you can’t go away and say, ‘I’ll think about it for a week.’ It’s a decision that has to be made then and there.”

     

    Solar PV panels feed into the hot water tank

    Although they were keen to have rainwater harvesting from the house, it didn’t prove to be cost effective. Instead they are harvesting the rainwater from the garage and greenhouse which will be used outdoors.

    They have solar PV panels on the roof which feed into the hot water tank when they produce an excess of electricity, and has meant that between March and October they haven’t needed the boiler on at all.

    In keeping with the history of the village having local orchards, they have planted an orchard area which also replaces some of the trees that had to be taken down for the build.

    With the simple thermal envelope they don’t have usable attic storage space. Instead the architects designed deep cupboards along the upstairs corridor and a walk-through library en-route to the study.

     

    Liz and Mike are advocates for anyone wanting to build a sustainable home of their own. While they say it may have cost slightly more than a standard house, the long-term benefits in terms of energy saved means it more than pays for itself.

    The other noticeable difference for them has been in terms of the air quality. Mike has found that he doesn’t sneeze as often as in the old house and that the regular air changes make it feel much fresher.

     

    Find out more

    Visit Liz and Mike’s blog

    Visit Architype’s website

    Find out more about Mike Whitfield Construction

     

    Transcript

    Download a transcript of the interview with Liz and Mike Hill.

    The Hub update

    We have a new video episode of the Buckinghamshire Passivhaus case study available to view for members in The Hub. Paul Jennings is carrying out the preliminary airtightness test and, not wanting to spoil the surprise too much, it’s the best he has ever tested!

     

    Please connect with me

  • HPH206 : What solar PV panels should I get for my roof? – with Robert Flynn from Solarbarn

    HPH206 : What solar PV panels should I get for my roof? – with Robert Flynn from Solarbarn

    Robert Flynn from Solarbarn explains how to choose a solar array to suit your needs.

    Interview with Robert Flynn

    After spending 25 years in the IT industry, Robert had a change of career and set up Solarbarn. It was 2010 and at a time when the government introduced the feed-in tariff scheme which kick-started the whole industry.

    While we have spoken on the podcast before about solar PV, we haven’t discussed what is required for the installation process.  As we have been following Solarbarn’s installation at Buckinghamshire Passivhaus, our video case study in The Hub, we thought we would speak to Robert to give us an idea of what you’ll need to think about if you’re planning to install solar PVs.

     

    Higher watt panels are only really needed on a small roof

    How many panels you need will depend on your roof area, how much energy you want to produce, and how much you are prepared to pay.

    According to Robert, you can’t really have too big a system. A large system may well produce more electricity than you need at a particular time, ie during the summer, but any surplus isn’t wasted as it is simply fed back into the distribution network to be used by others.

    A standard solar panel is now 300 watts, but you can get 360 watt panels if you want to pay extra for a more efficient product. Robert suggests if you have a large roof you don’t need to pay for the more expensive panels, as you have the space to install more of the cheaper, 300 watt panels. He says the pricier 360 watt panels are really only necessary where you have a small roof and typical sized panels aren’t going to give you the power you need.

     

    Roof pitch should be considered along with orientation

    A south facing array will produce more killowatt hours in a year than an array pointing east or west, or south-east or south-west.

    The shallower the pitch, the less of an issue orientation is. For example, with a shallow, 20 degree pitch, the panels are closer to pointing up in the air than at the horizon. A 45 degree pitch will make a difference as it is pointing more to the horizon. So a 45 degree pitch east/west will produce probably 25% less than the same array on a south facing roof.

    In terms of consumption however, there can be benefits of going east/west. An east facing array will produce a little more in the morning, and a west facing array will produce a bit more in the afternoon than a south facing array. A south facing array will give you a bigger peak at midday, with perhaps less in the morning and afternoon.

     

    Installations on new-builds are built “in-roof”

    As Buckinghamshire Passivhaus is a new-build they have been able to do an in-roof installation. The solar panels are part of the roof so it ends up being tidier than a retrofit would be. It also means you save on the cost of roof tiles as these are not required under the panels.

    The roof is built, felted and battened. At that stage Solarbarn would lay interlocking plastic flashing frames onto the battens which will ultimately hold the panels in place. The roofers return to tile the rest of the roof up to the flashing frames and making it watertight. The solar panels themselves aren’t put in place until the roofers have finished their work, to make sure they are protected and aren’t going to get damaged.

    At this installation the clients are using a power optimiser solution. A power optimiser on each solar panel means that the panels can work independently of each other, so if one is shaded for example, it wouldn’t affect the output on any of the others, which on a traditional wired system can be an issue.

    The distribution network operators need to be notified of systems up to 4 kilowatts after they have been installed. Anything over 4 kilowatts, as in the case of Buckinghamshire Passivhaus (7kW), needs to have their approval in advance as they need to be sure that the infrastructure is capable of taking the load when power is being injected back into the network.

    The solar array is first tested on a sunny day to make sure there is enough power going into all the panels and optimisers. The inverter is switched on and is paired with the optimisers at a safe 1 volt DC. When it is fully up and running it will be up to around 400 volts DC.

    The inverters get hot when producing a lot of power and eventually they will need replacing. They should last at least 5 years, and are usually guaranteed to last between 5 and 10 years. The inverter on the Buckinghamshire Passivhaus project is guaranteed for 12 years.

    Buckinghamshire Passivhaus

     

    Excess power can be diverted to an immersion heater

    A lot of customers of PV systems now have an immersion heater diverter, because in a lot of cases PV systems will produce a lot of energy when you don’t need it. This channels any surplus power that would otherwise be exported, into your immersion heater.

    Robert doesn’t feel that the economics of using batteries are quite right just yet, as they are expensive, don’t store quite enough and don’t last long enough. He does see a tipping point where improvement in battery technology plus escalating electricity prices will make batteries in solar PV installations a more feasible option.

    They have future-proofed Buckinghamshire Passivhaus by laying cables ready for batteries and technology to measure how much of the power they use and how much they export. By being able to measure their actual consumption they will be better placed when it comes to buying a battery array that is right for their needs.

     

    Ground solar arrays can be an option if space permits

    A solar panel pointing to the sun produces as much electricity on a frame in the ground as it does on the roof of a house, so space permitting, a ground installation might be an option. To make it worthwhile there usually needs to be a meaningful sized array, and for that size you will need to obtain planning consent. They need to be kept secure from children and animals endangering themselves, and also from theft. Typically, the ground arrays Solarbarn install for clients tend to be for large country houses that have swimming pools and huge oil consumption.

     

    Benefits are now more about self-consumption savings, rather than feed-in tariff payments

    People are always keen to know how soon the system will start paying back. Previously the benefits to be had were in the feed-in tariff payments, but nowadays the benefits are more to do with self-consumption savings, ie “producing lots of electricity, using it yourself and therefore not having to buy it from the grid.”

    “Generally, the people that were motivated purely on return on investment and how quickly they could get their money back are not those that install solar these days. The people that install solar these days are the people that want to do it because they know it’s the right thing to do. ”

    The benefits of installing a solar PV system at the time of building a house are that it is zero VAT (because it is a new build) and there are no scaffolding costs because the scaffolding is usually there already. Most of the work they do on new builds is now just considered an extra cost at the time of construction that will provide a huge ongoing benefit thereafter.

     

    The Hub

    For in depth videos following the progress of Buckinghamshire Passivhaus and other case studies you can join our members only area of The Hub. As well as step-by-step courses, you will also be able to join in with our monthly progress calls where members can share news of their self build projects and get advice from guest experts.

     

    Find out more

    Visit the website of Solarbarn

    Follow Solarbarn on Twitter

     

    Transcript

    Download a transcript of the interview with Robert Flynn.

    Please connect with me

  • HPH200 : 20 Self build tips (learned from 200 podcasts) – with Ben Adam-Smith

    HPH200 : 20 Self build tips (learned from 200 podcasts) – with Ben Adam-Smith

    Ben Adam-Smith shares 20 insights about self-building that he has learned while making 200 podcasts and also tackling his own project.

    1. There’s always something you can do to move your project forwards

    The road to building a house is a long one. There are also times when it can feel like it is never going to happen.

    Key challenges include finding land, securing finance, gaining planning consent and hiring a team.

    Just remember, where there’s a will there is a way. You can use your time to increase your knowledge or supplement funds, etc!

     

    2. Visit as many self build homes as possible

    There are many forms of research but by far the most effective is getting out and about, and visiting real eco homes.

    Get inspiration. Chat to self-builders who have made it through the process and discover what they’d do differently next time.

    Watch out for events like the International Passive House Open Days or Brighton Eco Open Houses, etc.

    Sometimes there will be opportunities to get onto construction sites too.

     

    3. Being flexible where you live should ensure you find land

    You might be lucky and have a garden plot to develop. Or perhaps you will buy the first piece of land you see!

    For most, though, this is one of the greatest challenges to overcome. And it goes without saying that urban plots can come with a hefty price tag, which is why relocating to where land is cheaper and more easy to come by is a smart move.

    Yes, it may mean leaving an area you love or moving further away from work, etc. If you are prepared to make this sacrifice then it may save a lot of time.

     

    4. Don’t dismiss custom build sites

    Custom build aims to make it simpler to build your own house. This video explains how it works (with an example in the Midlands).

    The benefits are that the land is much more affordable and, with initiatives like Right to Build, the local authority has a duty to make land available to potential self or custom builders.

    One of the downsides is that you are unlikely to get a plot in open countryside (which is perhaps what we all have in our minds!). The point here is to get over it! Even if you can only build on the edge of a developer site it is surely better than nothing? And quite often self or custom build streets have a great identity.

     

    5. Hire a good solicitor

    Buying land is much like buying a house: legally, there’s a lot to get your head around. Sometimes it can be even more complicated than buying a house!

    So, make sure you know what you’re getting yourself into. There’s a lot of money to be made in buying and selling land, and that means there are a few sharks out there. Hiring an experienced solicitor, whose daily business is land sales and acquisitions, should give you confidence going into this transaction.

     

    6. Don’t get too ambitious with your build route

    There are various procurement routes for building a house.

    At one end of the spectrum are package builds and hiring a main contractor, while at the other end is self-managing or even building with your own fair hands.

    If it’s your first time building a house, be careful not to take on too much (and perhaps underestimate what’s involved and how it will impact on your enjoyment of the project).

    Even just being the client can be a time-consuming and draining process.

     

    7. Embrace constraints

    Constraints are not always bad. Yes, you have to be careful of building on slopes and make sure you understand the extra cost that it will incur.

    In some projects, the constraints are not necessarily financial. For example, on my own project the majority of land is green belt and only a small section falls within the village boundary. That actually makes the decision of where to put the house quite simple!

    Constraints can also add character to a building.

    At Lime Tree Passivhaus the house had to arc around the root structure of a dominating lime tree (with a Tree Preservation Order on it). However, the constraints have led to a unique home, full of character.

     

    8. Design a house where you use all the space every day

    Architect Sarah Susanka taught me this one.

    It’s a great tip because it’s so easy to grasp.

    And it lets you have the things you want . . . so long as you use them!

     

    9. Try not to recreate old styles

    Building new is a huge opportunity to build for what’s best today.

    This includes making the most of light, energy efficiency, comfort, etc.

    While Victorian and Georgian housing stock is treasured in the UK, recreating these styles doesn’t make much sense. For example, fireplaces and chimneys are pretty much redundant when buildings can be airtight (and meet Passivhaus standard).

     

    10. Don’t be dissuaded from building a Passivhaus

    If you like the idea of building a house to Passivhaus standard, be wary of being dissuaded by those who haven’t done it or people who don’t sell products that can help achieve it.

    Take advice from people who have been there and done it. Once you’ve built a Passivhaus, very few people turn back.

     

    11. Like the people you’re hiring

    The process of building a house can take years, so when it comes to putting together your team it’s important they are people you can get on with. Yes, they need the skills but everything will feel a lot more enjoyable if there is harmony on all sides.

     

    12. Exercise restraint with your budget

    Unless you are experienced with managing budgets or you have a finite sum to play with, it is easy to spend more money than you planned!

    A few things run through your mind. You’re only doing this once and it’s your only opportunity to get the things you want. You can pay for it later!

    Of course nobody can stop you doing this, but it will have repercussions. If you’re struggling to find land it can be easy to assume more money will solve the problem. A splurge in one area will therefore mean reducing the budget in other areas or spending more overall. Fixtures and fittings is another area where people can get carried away.

    Remember, if possible, it’s better to build a slightly smaller house of higher quality than stretching to something bigger and then not being able to finish it properly.

     

    13. Focus on the big decisions

    Not all decisions carry the same weight. The land you buy, the build route you select and the team you assemble will have a major impact on your project.

    Yes, the devil is in the detail but making the right ‘big’ decisions will in turn make it easier to concentrate on the small stuff.

    Check out our podcast with Lloyd Alter from TreeHugger.

     

    14. Hiring consultants can be money well spent

    Nobody likes spending money when they don’t have to.

    However, consultants can add value (and even pay for themselves!).

    For example, on my own project I hired an interior designer. Some people might see this as an extravagance but she has helped us create a low cost kitchen that feels like something much more bespoke (and high end).

     

    15. Keep things simple

    It is all too easy to complicate our designs but the most ecological buildings tend to have something in common: simplicity.

    If the designs are simplified in the early part of the process they can often end up functioning much better.

    Check out our episodes with Nick Grant and Jonathan Hines.

     

    16. Engage in the planning process

    The UK system is often baffling. You will find huge variation in how it works, depending on where you are.

    One thing is for sure – it really helps if you engage with your local authority. Get feedback on initial designs and also, before any decision is made, check in with the planning officer to make sure everything is in order (from their perspective).

    Find out more about my own planning application.

     

    17. Install solar PV

    Assuming you have invested in the fabric of the building (and therefore have a high performance home), it makes sense to consider whether there is any potential for generating on your project.

    Often the most logical choice is to opt for solar PV because it’s not that expensive, will look better if installed on a new build home, and can pay back in a fairly short space of time.

     

    18. Being 100% ecological is virtually impossible

    Having a blank canvas is a huge opportunity to get as eco as possible.

    The problem is that there are always trade-offs. And sometimes with more money you just end up increasing the size of the building.

    So really this is about doing the best you can . . . and not beating yourself up. Remember, your house will be awesome!

     

    19. Don’t underestimate the time needed

    Building a house is a big project. Even if you’re choosing the main contractor or package route, don’t expect it to be a walk in the park!

    You will need time. A lot of time.

     

    20. Enjoy the journey

    For most people, building a home is a once-in-a-lifetime event!

    Of course the end product is important, but there is a lot to gain from the journey too.

    You will no doubt grow as a person. You’ll also learn a lot. And you’ll probably face your fair share of challenges.

    To get the most out of it, find an outlet for the highs as well as the lows. I’ve really enjoyed podcasting about my adventure. So, perhaps start a blog, keep a diary or just chat it out with friends.

     

    Please connect with me

  • HPH176 : A self build case study of ‘The Den’ Passivhaus – with Dennis and Nicola Merrigan

    HPH176 : A self build case study of ‘The Den’ Passivhaus – with Dennis and Nicola Merrigan

    Interview with Dennis and Nicola Merrigan

    Dennis and Nicola Merrigan talk about the highs and lows of their Passivhaus self-build project, sharing lessons learned.

     

     

    A ‘challenging’ plot at auction was affordable

    Dennis Merrigan had always wanted to build his own home and he loved the county of Dorset. He says they got lucky when their plot came up at auction, as they didn’t have to exceed their agreed budget. The neighbouring pub car park and pig farm may have put others off, but Dennis and Nicola are fond of the rare breed pigs and see the benefit of being close to the pub.

     

    The project inspired Nicola to become a Passivhaus advocate

    Nicola was initially overwhelmed by the build process and didn’t know what a Passivhaus was. The eco houses she had seen were on early episodes of Grand Designs, which normally showed “a sad looking woman putting sawdust down her composting toilet”! She was happy for Dennis to take the lead on the build but was adamant that she needed a flushing loo!

    As the build progressed she worked more closely with Dennis and fell in love with the story of Passivhaus. Becoming increasingly interested, she looked on Twitter for other self-builders. “Even though it’s something I’d never heard of before, I just thought it was really interesting and I wanted to learn more.”

    Planning permission informed the final design choices

    Dennis tweaked the existing planning consent to slightly increase the size of the house, but the planners turned down their initial red brick and stone design, saying they wanted something more modern.

    Dennis felt that “passive was the way to go” anyway, and had architect Paul Mallion of Conker Conservation in mind. Keeping Nicola in the loop, they tweaked the design as they went, deciding on timber frame for the construction. The second planning application imposed a height restriction but Dennis actually thinks the house looks better for it.

    Good neighbours can help to overcome challenges

    Dennis says they are lucky to get on very well with their neighbour. Together they solved some drainage problems for all concerned by using the neighbour’s suggestion of putting a sump on his land and building a drainage channel right through the Merrigan’s property.

    Manage the build with teamwork and communication

    During the build Nicola and Dennis were mostly away working, which Nicola wouldn’t recommend, saying that being near to the site is really important. However, with many phone calls to discuss details, client, builder and architect managed a lot of the project remotely. It was the builder’s first Passivhaus but being quite technical, he could understand the premise behind it. While Dennis’ architect only visited the site once during the build, he was very helpful on the phone.

    Dennis advises getting the building team onside for the air test. He says, “We played a little game on site that if they got it first time, there’d be a little bonus. And they did get it first time.” He adds that the air test is also a great way of testing that they’ve built it properly.

    Problems can become learning experiences

    The biggest challenge on the project came when the timber frame company went into liquidation. They had paid 50% upfront to have the timber frame made to their specifications.

    The contractor tried to minimise the damage by letting them take some of the materials and recommending another timber frame company. Good relations with the builder helped too, as he juggled his schedule.

    However, there was still a £20,000 deficit. Dennis’ tip to protect yourself against similar situations is to use a personal credit card for hefty deposits as that offers insurance.

    He remains philosophical, saying, “I think once you do get around things and overcome problems, then other problems that come up are very minor and you sort of get hardened to it.”

    Recycling can help solve budget issues

    They ended up with a lovely, finished house but no money left for a kitchen. However, Nicola says, “The gods of building take away and then give back.” Dennis works as an independent surveyor with loss adjusters on fire and flood claims. A very high-end kitchen shop had had a flood in the basement, but had a kitchen upstairs which had been written off. They were able to buy it at a manageable price and, though not the kitchen they would have designed, are really pleased with it.

    Nicola’s memories of the build process

    1. July 22nd 2012, first digger came to clear site

    2. Concrete was poured for foundations

    3. Timber frame went up – it looked like a house

    4. Siberian larch cladding went on – it looked even more like a house

    5. Fermacell boarding

    6. Kitchen went in – it was finally a home

    The little details make the difference

    Dennis says that finishing a property is all about detail. They have a good ventilation system but avoided ‘toys’, keeping things simple with timber floors upstairs and polished concrete floors downstairs. Details like aluminium guttering add refinement but nothing stands out on the roof. The solar PV panels are black and were built in. The solar thermal panels also ‘melt into the roof’, as they match the Fakro roof lights. (They also get the money back on the PV so they have a warm house and no bills.) Although told they wouldn’t need a log burner they put one in for looks. However, they are glad to have it to use occasionally when they haven’t been in the house for a while.

    The budget was difficult to manage

    Initial budgeting is hard and even Dennis’ builder wouldn’t work to a price having never done Passivhaus. Dennis agreed to pay the labour on a daily basis, so it was hard to stick to the budget. For example, the Fermacell is very heavy so took a lot longer and cost a lot more than plasterboard would have.

    Dennis admits that he made mistakes but they did have enough resources to finish the project. For example, they had to wait a little time but they did manage to get the kitchen.

    Nicola advises to not only budget for the house but also the surrounding area, something they didn’t do. Their neighbour came to their rescue again, doing the landscaping with his digger.

    5 tips for people wanting to build their own home

    Dennis and Nicola share some great advice for self-builders:

    • Be prepared: finding land is really hard
    • You need a good architect that you get on with
    • Get your finances in place – they used the Ecology Building Society and couldn’t fault them; furthermore, have a contingency; money can be a big worry, so don’t start without the project fully resourced.
    • Consider the form of contract; are you going to get somebody to do the whole thing or part-manage it yourself?
    • Especially with a Passivhaus, decide all the detail before you start because you can’t change things easily; even moving the structure inside is very hard because of the ventilation system.

    Dennis notes everybody will have different challenges with the build itself. However, once you’re in the house and benefitting from it, you forget all the problems. He concludes, “It’s worth doing. I’d recommend it, but you need to know what you’re taking on.”

     

    Find out more

    Conker Conservation

    Follow Nicola on Twitter

    Transcript

    Download a transcript of the interview with Dennis and Nicola Merrigan

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  • HPH082 : Do I Need Solar Photovoltaic (PV)? – with David Winterton from Ecological Design

    HPH082 : Do I Need Solar Photovoltaic (PV)? – with David Winterton from Ecological Design

    David Winterton from Sydney-based consultancy Ecological Design gives us a rundown of solar photovoltaic (solar PV). We find out how it works, what the key considerations are and why prices of PV panels always seem to be coming down!

    David Winterton Photo

     

    Interview with David Winterton

    Having travelled a lot over the years, David feels that sustainability offers a deeper sense of connection. He’s witnessed first hand how indigenous communities have worked within their natural environment to create better places to live. And David believes that the same thing applies in our cities, which should be bustling, culturally inviting and invigorating. Sustainability is about better ways to live.

     

    Around 1 Million People in Australia Live Off-Grid

    The situation in Australia is unique because of the incredibly high levels of solar resources. Coupled with high energy prices and a decrease in the price of PV (Photovoltaic) panels, it seems an obvious choice for many to live off-grid. Some states in Australia have over 30% of their energy supplied by renewables.

     

    Solar Panels and Solar PV defined

    When people talk of solar panels they might think of them being for hot water. Solar PVs in this conversation relate to the technology which converts sunlight directly into electricity.

     

    The Fundamental Thing to Understand About Solar PV is That it’s Static

    While other forms of electrical generation, such as hydro, wind and nuclear, are all based on parts spinning around, the PV’s remain static. The sun coming in creates an electrical current between the different wafers of silicone. From there the DC output from the panels is converted, using an inverter, into AC.

     

    A Number of Factors Have Contributed to The Downward Price Curve of Solar PV

    With initial investments in plants and equipment being paid off, and improvements in the manufacturing processes and the way silicone is produced, the costs of panels (but not labour) have fallen.

    David emphasises however that he would never recommend selecting panels purely based on price. With most companies offering between 10 and 25 year warranties they are going to be in the building fabric of communities for a long time so it is important that you make the right investment. He gives inverters (the part which converts DC into AC) which should be lasting 10 years as a case in point. Some of the poorer quality ones have been failing within 5 years.

     

    We Should Be looking at Matching Our Energy Consumption With Our Yield

    Previously it was the case that we tried to just get the highest yields out of the systems. With so little being paid for over-production that goes back to the grid, it actually makes sense for your peak levels being generated to be at the peak time that you will need it. For example, north facing panels (in Australia) would have a peak production in the middle of the day, and if you’re not there in the middle of the day then it’s not matching your energy requirements. It might be better to have two strings of panels with an east-west array that will be giving you a peak production closer to your waking up and getting home times of day.

    The energy density of modern panels has improved meaning that now you can get a lot more power into a smaller panel. This therefore makes them viable to use in more shaded areas where once it wouldn’t have made financial sense to do so.

     

    A Small Energy Storage System Can Avoid The Reliance on Peak Grid Energy Prices

    With energy prices going up over 45cents a kw hour during the energy usage peak at night, it might be worth having a battery system to store any excess produced during the day so you don’t have to depend on the expensive energy during this short period of time.

    David sees a similar trajectory that has happened with the number of people having solar PV over the last 10 years, happening with battery storage.

     

    Some Key Considerations:

    • Avoid low quality systems.
    • Future proofing – in terms of battery storage it is worth checking to ensure that any system you are considering has the capacity to feed into a battery storage option.
    • Understand your shading – shading on any one of your panels will result in a drop in voltage as it will actually revert to the lowest voltage across all of the panels. A smaller system designed with a different orientation might actually better meet your energy needs.
    • Energy efficiency first – there’s always energy efficiency to be found in a house at some level so it is always best to focus on this first.
    • Avoid companies which say you can upgrade for example a 3kw inverter to a 5kw inverter in the future – David emphasises that this is not how inverters work!
    • Ask solar installers for production graphs of how much energy you will produce, which you can then overlay with your energy consumption.
    • Talk to neighbours – particularly those with PV to see how it can work within the community.

     

    There is a Place Within Energy Markets For Community Energy

    David feels that community energy can play a strong part. Even if you’re unable to put solar PV on your home it is important to understand community initiatives in your area and what they will mean for the future. He gives the example of New South Wales where he believes that political decisions that have been made about their energy systems have not been in the interests of the community. He stresses the importance of understanding the governance and the capacity for making changes to get those things to work.

     

    Find Out More

    Visit Ecological Design’s website

     

    Transcript

    Download a transcript of the interview with David Winterton.

     

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