Tag: overheating

HPH263 :A step-by-step EnerPHit retrofit of a mid-terrace home – with Harry Paticas from Arboreal Architecture

Harry Paticas of Arboreal Architecture explains why care and hard work have been so important to the retrofit of his 1978 mid-terrace townhouse.

© Agnese Sanvito

Interview with Harry Paticas

Harry has a background in art and maths, which he then followed with a degree in architecture. He says the turning point in his twelve years in practice as Arboreal Architecture was taking the Passivhaus training course and suddenly being able to understand how buildings perform.

Together with his interest in building performance and the natural world, he also has a passion for retrofit, and is currently getting towards the halfway point of a phased retrofit of his own house, a project which was overall winner at the inaugural ASBP Awards 2019.

“When you put passion in, you get something out”

The house was purchased in 2016 with the aim of doing a retrofit project. Although they had intended on finding something a bit cheaper so they would have more money to spend on the works, this house cost rather more than they had budgeted for which is the reason they are not currently as far along as they had hoped.

It is a south facing, slightly staggered mid-terrace property. It is a combination of a solid brick and block front wall that is tile clad, while the back wall is brick both sides with a cavity.

© Agnese Sanvito

It has been an intensive couple of years working on the house, with every Sunday taken up by long hours of DIY. It has been a massive learning journey which Harry says has also been of benefit professionally.

Not only has the DIY element of the project been hugely rewarding, but it works in parallel with his professional role where he can now speak even more confidently and knowledgeably to clients. This could be about how the MVHR functions, how often you need to change the filters, how the pipes connect etc. Likewise, it aids with speaking to builders and helping them do a better job, which gains more respect from them in turn.

The strategy involves four phases

The first phase involved work being carried out before they moved in. They had sold a property and were renting so that they could get any of the dangerous, dusty and cold work out of the way while living in their rental accommodation. This included asbestos removal from ceilings, airtightness works to the ceiling on the top floor, putting in and taping vapour block boards to each other and to the walls, adding insulation to the loft, making the house secure and weathertight and installing three triple glazed windows.

Generally the plan has been to work from the top of the house down to the bottom. Following the loft works and triple glazing to the front elevation they added insulation to the walls of those rooms. By this time they were living in the house and noticeably felt the thermal shift during the winter weekend when they added the cork insulation to the walls.

A key part of the strategy was maintaining good quality ventilation before the MVHR unit was even installed. With the existing leaky double glazing they knew it wouldn’t be a problem, but when they were replaced with the triple glazing they specified night vents. These allow the handle to be put to 45 degrees off the vertical which gives a 3mm opening in the window at the top. This meant they could maintain decent air quality as an interim measure without the need for installing trickle vents.

By doing lots of monitoring of particulate matter, nitrous oxide, carbon dioxide, temperature and moisture content, they could use the information to decide whether night vents should be open or not.

Harry is currently finishing off bits of airtightness work and interior decorating of phase two before working on the next big phase which will be working out where the living space is going to be. The plans they submitted to the Passivhaus Institute had it on the first floor, but they’re now thinking of having it on the ground floor.

© Agnese Sanvito

According to their EnerPHit retrofit plan, the next phase is to temporarily insulate the garage door. This will instantly reduce heat loss through the whole of the living room floor, the ground floor hallway and a back wall of the garage. In order to do that they will need to block the door and create a new entrance into the garage.

Along with insulating the porch and insulation to the bathroom, these will form phase three, with phase four being the ground floor front and back insulation, and insulation to the floor.

Cork has been used for internal insulation

Harry was always going to use an insulation material that was from renewable sources. He also wanted something that wouldn’t off-gas but be neutral in terms of air quality.

His work with Jane Anderson on embodied and sequestered energy in a range of insulation materials has shown that cork actually has lower embodied energy than wood fibre, and is very good on both counts.

It hasn’t performed as well as hoped in the heat

While internal temperatures have reached 27 degrees, it hasn’t overheated in the Passivhaus terms of over 20 degrees for 10% of the year. With the new windows they are getting 20% less sun through, but with the cork they’re not getting much effect from decrement delay. They have a medium thermal mass and the top floor doesn’t cool down very quickly because of the blockwork walls and brick party walls.

Currently being made are three bright yellow sails which can be attached to the front of the house and shade 100% of the top two windows and over 50% of the large living room window. They will provide a low carbon, low tech solution to shading and reducing overheating, and which can be packed away in a bag in the loft when not needed for the rest of the year. They will also be able to judge their effectiveness scientifically as they have installed sensors on the inside and outside of various rooms of both theirs, and their neighbour’s house for comparison.

It’s also about respecting materials that are already in the building

The process they have adopted has been to try not to replace something if it actually works quite well.

“So there’s a little bit more of a lean towards embodied carbon, rather than very demanding interior design aesthetics.”

This has led to what Harry calls some ‘fun moments’ and to a little bit of variation, which they’re accepting of and saying that’s what this is about, rather than trying to put his architectural stamp on everything and making it as perfect as possible.

It has been an education for his son

With Harry’s son soon turning eight, he was keen for him to be involved and remember the experience as much as possible, with a deep understanding of what it is they were doing and why.

With only a little encouragement at first, his son has been producing a series of A3 posters with images, annotations and diagrams, about cork, airtightness, a thermographic survey, insulation and mechanical ventilation with heat recovery.

© Agnese Sanvito

His teacher engaged with the process and has encouraged him to display them in school and do presentations about them to his class.

A direct result of the school presentations is that Harry is starting a charity or community interest company which will be about retrofitting schools. He will be delivering thermal performance workshops to school children and doing research with them where they look at the fabric of their classrooms and the school and coming up with a retrofit masterplan.

There have been particularly pleasing elements

Having never had them before, Harry particularly loves the triple glazed windows, which is an opinion shared by visitors to the house. They are inward opening with a central flying mullion which allows them to open up a whole elevation and achieve very rapid night time cooling.

© Agnese Sanvito

Another favourite feature is the MVHR unit. They still open windows when they want, but for general air quality which has been backed up with numerical evidence from their monitoring, it has been particularly pleasing.

© Agnese Sanvito

Harry says that working with and getting to know materials has also been lots of fun, particularly with the cork.

Find out more

Visit the website of Arboreal Architecture

Follow Harry Paticas on Twitter

Support Harry’s petition for zero rate VAT on deep retrofit

Transcript

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September 8, 2019
HPH255 : How do you specify high performance windows? – with Chris Herring

Chris Herring, Director at Green Building Store, explains why careful consideration should be given when specifying windows.

Interview with Chris Herring

With a father who was a keen environmentalist, Chris was raised with an awareness of ecological issues from a young age. A builder by trade he has been in the industry since the 1980s and is now a director at Green Building Store.

Windows aren’t just another building element, they’re a critical one

Chris emphasises how important it is to get the right windows on a building project. They matter to the feel of the house and how we feel in the house.

They have physical and architectural functions, they’re part of the fabric and the thermal performance, there are safety issues in that you need to be able to get out of them, they might have to protect against fire, and obviously let light in.

When it comes to specifying windows and bringing all that together, many of those functions can actually be in conflict with one another. Often it can be a case of finding the best compromise.

Manufacturers and suppliers should be part of the design process

With components and performance levels in buildings becoming more complex, Chris would like to see manufacturers and suppliers becoming more part of the team. They can bring their expertise at an earlier point and be more involved in helping to specify the right windows for the job.

Triple glazing as standard

Chris says that with a little more attention to detail and extra skill, a building can, and should, be made considerably better. With the thermal envelope key to the performance of the building, triple glazing should be standard in the UK climate to make it work.

“So, we need triple glazing because the Passivhaus Standard drives us there, and it drives us there because the building physics drives us there. The key to that is, in many ways, comfort, because we need every surface to be warm. Because then we don’t need to heat the building very much. As soon as you get a cold spot, you’re going to get mould, you’re going to get discomfort, you’ve got down-drafting, you’ve got all these problems. So, the system stops working. So, it’s the building as part of the system that drives us to triple glazing in this climate.”

Determine the energy balance

There is more energy loss from windows than any other part of the fabric of a building. Their thermal transmission will always be a weak point, but they do also bring solar heat into the building. That energy balance between the gain and the losses is what’s so significant with windows.

Being around 10-15% of the area of the building, they typically make up a disproportionate amount (roughly 30%) of the losses.

If you’re north facing you have no significant energy balance. It’s just a loss so the logic then would be to have small windows.

With a Passivhaus, it’s about looking at how to get the best balance between those window heat losses and gains, and typically they’re approximately in balance, so are neutral in their effect.

Understand their performance

Chris thinks it’s worth taking time to understand a little bit about these values so you can understand more about the performance, rather than just being led by someone else.

U-value: the heat loss through the piece of glass – measured as the heat loss per metre squared per degree kelvin difference between inside and outside. So, watts per metre squared K (W/m²K).

A measurement can also be taken for the heat loss through the window frame (usually worse than through the glass).

The Psi-value is the heat that is lost through the edge of the glass where it meets the frame. That is measured as a heat loss per metre perimeter of glass.

Those three factors, the frame value, the glass value and the Psi value, are added together to give the U-value of the total window.

Each window will have a different U-value so they are all modelled separately in PHPP.

G-value: this is the measurement of how much solar gain actually gets through the glass. The more panes and coatings there are, the more you restrict the amount of sun that can get through.

In a triple-glazed window it would likely be in the 50-60% range. In double-glazed it might be around 70%, and in single-glazed closer to 80-90%.

Lambda-values: this relates to thermal conductivity. It applies to every material and is actually the inherent quality of the material.

“Obviously, if we take a piece of aluminium or a piece of expanded polystyrene, they’ve got very different amounts of thermal conductivity, the amount that heat can get through per metre thickness of that material. So, a λ-value is given as the heat loss, which is given in watts, per metre thickness of the material per degree difference between the inside and the outside. So, that’s watts per metre K (W/mK). So, the metre is the thickness of the material.
It’s quite different from the U-value, which is about an area value, if you like; it’s per metre squared. And we’ll use that thermal conductivity to then calculate the U-value.”

PHPP calculates the U-value

Chris explains that PHPP has a standard calculation which takes the heat loss from the glass, the heat loss from the edge of the glass and the heat loss from the frame, and adds them together. It calculates the total heat loss and gives the U-value of the window.

PHPP also builds in the Psi-value for the installation, which is given as the heat loss per metre perimeter of the window. To get the installed value for the window, that heat loss is added to the total heat loss of the window. The calculation shows how important it is that the window is installed properly, and the implications for if it’s not. A triple-glazed window installed badly for example, could effectively end up with the performance of a double-glazed unit.

“So, that detailing is incredibly important and something people struggle with and architects struggle with.
Coming back to what the suppliers and manufacturers offer, I think this extra value of supporting people further, supporting architects, supporting clients, is actually critical. I think it will become more and more important for suppliers to add those extra values to supply. It’s not just a widget that’s somebody else’s problem how they fit it, the supplier should be going further down the chain and advising people how to fit it and helping them to get that detailing right.”

Understand risks of overheating

While PHPP gives an idea of overheating across the whole building, it doesn’t differentiate by room. Understanding some of the causes can be helpful. A full height window for example, while perhaps desired architecturally, won’t increase the light level a great deal because you’re only lighting quite a small area (it’s higher light that has more effect in terms of lighting the building). However, it will result in increased overheating because it’s still heating the floor up fairly close to the window, and that’s heating the room up.

Trying to get round that by using shading would need a much bigger overhang to fully shade the window, which is probably unlikely to be used. So in that case, although the overhang can be shading the top half of the window, the bottom half going down to the floor is not shaded and will result in overheating.

Something else to bear in mind is that a window above 800mm from the floor doesn’t require safety glazing, which can make considerable cost savings.

Timber-clad windows are recommended

Green Building Store made the decision some years ago that triple glazed would be the only window they would offer, but there are different types of cladding. They don’t engage very much in the conversation around uPVC windows because the evidence they’ve seen shows how environmentally damaging they are.

There are also questions around the environmental impact of aluminium clad windows. The energy use in smelting and even recycling aluminium is quite high.

“We’ve always tended to encourage people to go to non-aluminium clad windows because we think that the evidence seems to show that it lowers the environmental impact of the window. We have bowed to demand, if you like, and now offer aluminium clad as well.”

Timber windows do need painting every 10 years and adding up that expense will probably make it similar to the cost of aluminium cladding. But what most suppliers won’t tell you is that the aluminium cladding will fade over time and you will likely lose the appearance within 20 or 30 years.

“If people come to us and ask for aluminium clad, we’ll give them aluminium clad. If they want to discuss the issues then we’ll certainly discuss that with them. And we do outline some of that information on our website as well, so that people can think about those issues.”

Find out more

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June 19, 2019
HPH251 : Adopting a ‘do less, but better’ mentality for your house build – with Charlie Luxton

Charlie Luxton shares lessons he’s learnt from visiting projects on Building The Dream, running an architectural practice and completing his own self build.

Interview with Charlie Luxton

With a childhood spent building treehouses and dens from straw bales and pallets, it was perhaps no surprise that Charlie Luxton entered into a career in architecture.

Having traveled widely, his eyes were opened to how people lived and how the world was changing, and he found himself questioning the way things were done. Although it wasn’t taught at university, by his second year of study he had developed his lasting passion for sustainability in architecture.

Do less, but better

This is the principle that Charlie tries to instill at his practice. With the process of building a house having so much embodied energy, he believes there’s a real responsibility to do it well and make sure that it’s going to last a long time. It’s not about making it as big as you can build, but it might mean making it a bit smaller, but making it better.

“If you build well and you build sustainably, you will enjoy the space so much more. Because well-designed and well-built, a small house can be just as successful and provide as much usable space as a badly designed large house.”

He explains that often people will plan to build extra bedrooms that they don’t really need. And statistically with people that self build staying there for around 20 years, effectively they’re building in what someone else might want in 20 years time, not what they need for living in it themselves.

Charlie believes that if the architecture and the build quality are right, then a future sale price will reflect that, and there are bound to be purchasers who will want the house that you designed as being right for yourselves at that time.

You’re only really ready to do your first self build, after you’ve done your first self build!

While people building a house can be very good at researching what things they are going to buy to put in it, they can often fail to research and understand what kind of house they want to live in and how they want it to feel.

Pay for quality of design

Charlie regularly meets people who haven’t been prepared to spend enough money on good design, but by visiting a well designed, sustainable home it can help them bring value to their project.

“If people did more research about the varied outcomes of people working with really good design specialists or without them, they would find it much easier to justify the expenditure of a design professional. And I think they would see that the outcomes are noticeably better.”

He elaborates on the importance of finding the right designer, not necessarily a local one. He says many can just be going through the motions of designing the same old thing, without looking at context, the specifics of the brief, the specifics of the site or even orientation to the sun.

By visiting a couple of homes they have designed, and that are similar, you can get a good indication of how your own house might feel.

Although getting a good designer on board may come at a premium, it can be as a result of the hours spent detailing to get it right.

“But if the person you’re paying is designing your building and dictating every single element that goes into that building and how they come together, surely it’s some of the most important money you’re going to spend.”

He was a terrible client on his own self build!

Charlie moved to his current location 12 years ago, buying a thatched cottage with an outbuilding that had conversion potential and just under an acre of land. Wanting more accommodation and office space, but knowing they wouldn’t get permission to extend the cottage, they decided to knock down the outbuilding and build a new home.

It took three iterations to get to planning, and then a further two redesigns to come up with the final approved designs. Original approval was for a two storey building, but Charlie changed this to a single storey dwelling with a vegetable garden on the roof, where he would still be able to chat to the neighbours!

Because of the nature of his work, Charlie admits he put a lot of pressure on himself to come up with something “better than good”.

Overheating was his main concern

The brief was for a low-energy, sustainable family home, with the elements of Passivhaus but without getting it certified.

“I don’t think you can ignore architecture and just focus solely on the environment. Because if a building is really good architecturally and ninety-five percent as good as a full passive building, to me that’s got real validity. And I think there are always choices to be made about why you’re putting in a window for a view or for overheating or for heat loss.
So, it’s a hugely complicated thing. And I’m not saying we’ve got it right and we always have to be refocusing our efforts. That’s what is brilliant about Passivhaus. It gives you that standard, that gate, yes or no. Are you in or out? As soon as you’re not doing it, it’s a bit more vague and you can start to abuse that or drift away from the purity.”

In hindsight, Charlie says he should have modeled it in PHPP, as his greatest concern at the time was overheating.

From Homebuilding & Renovating’s YouTube channel

With one side being dug into a hillside, they wanted a lot of glazing on the other to make the connection with the landscape, and have also used rooflights. They have used an active control system with external louvering to counter any overheating issues.

The bungalow is connected to the cottage via a highly insulated district heating main, with rainwater harvesting coming down, and heating able to go back and forth.

It was around ten years ago that they refurbished the main cottage and they were determined to do it as sustainably as possible.

They added wood fibre and lime internal insulation, dug out the floors and put in 200mm of insulation underneath, insulated under the thatch, and installed a rainwater harvesting system. They used only European hardwoods which mostly came from trees in Scotland that were old or diseased and would be felled anyway. The cottage is now used as their office.

Build your own and learn from your mistakes

Charlie would encourage anyone who is an architectural professional to try building their own house, for their own learning progression, or at least do proper post-occupancy analysis, which he sees there being a real lack of in the industry.

Planning constraints dictated the build system

Planning constraints meant the bungalow needed to be be built into the hillside, which inevitably meant a reinforced concrete build system.

The structural engineer calculations worked out that the force onto the back of the entire wall was equivalent to three tonnes per square metre. That also meant a thick floor slab and concrete again to hold the 200mm wildflower roof.

The external walls are 140mm concrete block on the inside with a timber I-beam, and blown with a high-performing polystyrene bead.

They used granulated ground blast furnace slag, which reduces the amount of concrete and CO₂. To further try and compensate for the amount of concrete used, they have underfloor heating and the concrete is the floor finish.

“We’re using the concrete block a) to give a rigidity, a sturdiness to the walls; b) to give that thermal mass so we can iron out any temperature fluctuations with a thermally massive building. So, that’s how you try to make what is on one level a problem, using so much concrete, into something of a strength.”

Using local materials was important

Inspiration for the building came from the railway viaduct piers that they look out towards. They were able to use local stone from a quarry just three and a half miles away, and Corten as a reference to the local steel industry. Charlie admits that his other inspiration for the outside of the building was less conventional, being from the railway bridges around the M25!

Management of the job was the biggest challenge

He explains that he does architecture and TV and is no builder, but he took on the role of principal contractor. Apart from a few bags of sand and cement he actually did all the purchasing himself, which took a huge amount of time.

He also cites a particularly trying time as being when there was a mistake with the plastering. Until that point everything had being going well, but it came at the time they were exhausted, and running out of money and emotional strength.

From Homebuilding & Renovating’s YouTube channel

Today’s overinvestment is tomorrow’s bargain

Charlie believes if possible it’s best not to take a short-term view of what you should invest. With build costs outstripping inflation significantly, if you end up going further and spending more than you intended, then it will still be cheaper than if you did it in ten or fifteen years’ time.

“So, actually if you do it right now, you won’t go back and redo it. So, a) you save wasted materials of going back and redoing something; and b) you save the cost uplift that’s likely to happen.”

The other thing he learnt was, in the search for perfection the one thing you’re bound to find is insanity.

“I think trying to finish this house, you’ve got to let things go. You’ve got to be proportionate. And I think a lot of people really struggle with that. I think if you accept early on that it’s never going to be perfect, as much as I’m not perfect, no-one I know is perfect, then I think you’ll find it a much easier ride.”

Don’t be afraid to use specialists

Charlie’s advice would be to spend time really working out your cost plan early on. He used his quantity surveyor’s spreadsheet of costs to then populate and amend figures himself, and found this to be a useful guide to understand where he was going. He believes people often kid themselves about the real cost of things, and if they knew the real cost they would never do it.

He suggests tendering for items early on and also going to specialist suppliers. They might appear to be more expensive but they’ll also be a lot less hassle. With the expertise of doing their one thing day in and day out they can often be very quick and good value in hindsight.

Find out more

Visit the website of Charlie Luxton Design

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Transcript

Download a transcript of the interview with Charlie-Luxton.

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May 24, 2019
HPH147 : A Passivhaus standard Q & A – with Elrond Burrell
Architect Elrond Burrell provides answers to a few common questions that people have about the Passivhaus standard.

Interview with Elrond Burrell

As part of Ben Adam-Smith’s video work, podcasts and meeting with other self builders, he is often asked questions about the Passivhaus standard that he doesn’t know how to answer. He recently took the opportunity to put those questions to Elrond Burrell.

Born in New Zealand, Elrond has been working in the UK for the last 18 years. As well as being a qualified Architect and Associate at Architype, he writes a plain speaking and successful blog about Passivhaus, which has a global following. Before he returns to New Zealand we caught up with him to tap into his Passivhaus expertise, and also find out what his plans are for the future.

Is it necessary to have a heating system in a small Passivhaus?

This will depend on the specific heating demand of the project. It is possible on a very small project to get away with just a portable electric heater, bathroom heated towel rail or similar.

A risk of doing this is that if the house is sold or has different occupants they might not be fully aware of this and find that they do get a little cold on rare days of the year. Elrond suggests a more robust approach is to just put in a very small heating system.

Another thing to consider is that heating is only one part of the equation in terms of power consumption, and actually in a Passivhaus building, providing the hot water can quite often be a bigger heating load than providing the space heating.

“And so you tend to design a system that can provide all the hot water needs for the year, and have enough capacity in that to provide the small amount of heating that you might need in the cold days of the year.”

Why might you not want the heat source to be incorporated into the ventilation system?

Firstly, air only has the capacity to carry a certain amount of heat. Water and solid surfaces can carry and radiate much more heat than air can. If you need more heat than the air can provide then you can’t do it all through the ventilation system.

Secondly, you need fresh air all of the time! In order to guarantee good quality, fresh, filtered air all year round, then you need the ventilation system running all the time. You don’t necessarily want the heating system running all the time though. There may also be times when you want more heating than the ventilation can provide. Although there is some logic in combining them, they are two quite separate systems in a way.

To avoid overheating, can you integrate a cooling system into the house?

The Passivhaus standard allows for 15kW annually of heating per m², and likewise allows for the same of cooling if required. In a relatively mild climate like the UK you shouldn’t need cooling if you’re designing the building well. In much warmer climates you would expect that in a very efficient Passivhaus you may have a small amount of cooling, the same way you have a small amount of heating. Like the heating, it can be provided by the ventilation system or separately through a radiant or other cooling system.

In a Passivhaus project you wouldn’t put something in as a ‘just in case’ measure, because using the Passive House Planning Package (PHPP) software you can very accurately design and predict how the building will perform.

“So you shouldn’t be putting in stuff just for the eventuality that it might be needed and you should be designing it to get it so you don’t have that need.”

Does it make sense to have mechanical blinds to give you a sense of control?

More commonly used in Europe and the US than they are in the UK, Ben says that some of the people he comes across like to have the mechanical blinds to give them an extra bit of control. Elrond suggests that it is important for people to feel in control of their environment and that they can modify and change things if they wish to. They shouldn’t feel that they’re living in a house which they’re not allowed to touch or interact with, so if people feel strongly about having the blinds then they should go with it.

Something to be wary of is if they’re built within the window it can be an expensive operation to fix or replace them if something goes wrong.

“So it’s not something specific to Passivhaus but it’s more the approach a lot of people that come to Passivhaus want to take is really simplification and trying to avoid moving parts and things that might go wrong at a later stage.”

The power consumption and how they get detailed and built into the building will also need to be accounted for in the Passivhaus modelling.

How adaptive can the house be in terms of comfort?

Regarding temperature, this will come partly come down to the design of the building. The upstairs rooms are likely to be a little warmer so personal preference about whether to sleep in a cooler or warmer room may be a contributing factor to the design. And if heat is being delivered by the ventilation system then wherever the air is being delivered is going to be warmer than where it’s being extracted from. If you’re heating through a radiant rather than ventilation system, then these can be located in areas where you would want to feel warmer.

Another thing about adaptive comfort, which is in the Passivhaus Institute guidance, is ensuring that all occupied rooms have got windows that can be opened.

Future Projects

When Elrond returns to live in New Zealand in the near future he will be continuing with his blog at elrondburrell.com. He has also set up a new company, VIA architecture, and will be offering a ‘PHeasibility’ service.

It is important to Elrond to embody his own personal values in the work he does. “So not just what looks like sustainability but what really counts in the details and in the putting it all together.” VIA architecture is based on the idea “that particularly using the Passivhaus standard we should be able to use architecture to transform the quality of peoples’ lives and so it’s really a process of using architecture to get to a good outcome. Whether it’s a really healthy, comfortable home, or a school or a business or what-have-you. And so architecture is kind of the process to get there rather than the end product in itself.”

The PHeasibility service involves Elrond taking early designs and running them through the PHPP in a basic way, before a commitment to employ a Passivhaus designer has been taken. It will give an indication for self builders or architects without Passivhaus experience, as to what might be involved, taking into account constraints and design, for the building to achieve the Passivhaus standard. It will look at the key aspects which determine if the fabric, orientation, windows etc are going to be of the required standard. They will then be better informed as to whether to pursue the certification.

Find out more about PHeasibility

Visit the PHeasibility website

Special offer: subscribers to Elrond’s blog can get Pheasibility for £495 instead of the standard £745 if they book it in September or October. To subscribe to the blog (direct link to subscribe: http://elrondburrell.com/hph_subscribe) and then send an email to PHeasibility@elrondburrell.com

Find out more about VIA Architecture

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Relevant Articles

5 things to know about Passivhaus

Passivhaus Overheating: Design it out

Passivhaus: Solar Orientation Doesn’t Matter. Or Does It?

Transcript

Download a transcript of the interview with Elrond Burrell.

The Hub update

The Hub has now been going for a year and we’d like to thank the founding members who have put their faith in us. We’re always looking at ways to improve what we are offering and in the coming months we’ll be trying to make the modules even more step by step and easy to follow.

Our second case study is now under way, the Buckinghamshire Passivhaus, headed up by architect Janet Cotterill from CTT Sustainable Architecture. The project first started out as a retrofit so find out why it didn’t continue that way, and went on to be a new build.

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September 21, 2016
HPH114 : The long road to high performance homes – with David Olivier from Energy Advisory Associates
David Olivier from Energy Advisory Associates shares some of his personal and professional experience of creating energy-efficient homes.

Interview with David Olivier

David Olivier has 35 years of experience in supporting UK architects and engineers on leading energy-conscious building designs. He was involved in environmental research early in his career before starting his own freelance business advising people on energy and environmental improvements. In 2012 he moved into his own passive solar energy self build home in Herefordshire.

National policy emphasis should be on investment in domestic energy conservation

When David left education in the mid 1970s he went to work for an environmental research body linked to Friends of the Earth, called Earth Resources Research. While there he worked with three colleagues on a study of the long term energy needs of the UK and the potential for meeting them with renewable energy combined with better energy efficiency.

Published in 1983, the report concluded that by 2025, if the political will was there, the UK could provide around two thirds of its energy from renewables. It also concluded that the UK could improve its energy efficiency by about threefold over 50 years, with the result that it could reduce its energy consumption and increase the standard of living of most people.

Back in the ’70s the concern was more about the price of oil and heating bills rather than CO₂ emissions. Even today, there is still the concern about energy prices. David suggests that despite inaction and lack of interest from governments, there has been an improvement in energy efficiency over time in the UK. The use of energy efficient lightbulbs for example has seen a marked effect on electricity consumption.

David would like to see a shift in policy away from national investment in nuclear energy and fracking, and instead see that money invested in energy conservation in the domestic sector, such as subsidising the cost of buying highly energy efficient domestic appliances.

Aim for a higher standard than UK building regulations

David suggests that if you’re looking to self build you should ignore the standards set by UK building regulations and aim to exceed them. He explains that the standards set in other European countries are far superior to our own, with Sweden for example having higher building standards in the 1980s than we have today. He recommends applying more insulation and thinking about the Passivhaus standard which will give you a more comfortable, draught-free environment.

Don’t upset the planners!

When it comes to securing a building plot David’s advice is, if you have the option, consider a move to parts of East Anglia, Scotland or Wales, where they are more readily available. In case of uncertainty and to avoid overpaying for it, he would recommend you have a chartered surveyor give a valuation.

David suggests looking at the council planning policies for the areas in which you are searching for a plot. His search area incorporated 6 different councils, with 6 very different planning policies ranging from relaxed and positive to completely draconian! He had a 6 month long battle to reverse the decision of a junior planning officer on what really should have been a minor point. If in any doubt about this stage, he recommends first consulting a planning expert before liaising with council officers. Another suggestion is to quote to officials parts of the Self-Build and Custom Housebuilding Act 2015, which is an act that puts a legal duty on the local authority to make efforts to help self-builders obtain serviced plots.

Future-proof your house design

Always consider that if you’re planning to self build you could be living in the finished house for 10-20 years or more, and over that time you’re going to want to make heating it affordable, no matter what the future holds. Even if you’re building in a town David recommends orientating the house towards the sun.

“Even at the present day energy prices you can justify doing a lot more than the UK building regulations require you to do when you insulate a new house.”

Use passive solar energy long before considering solar PVs

David moved into his house in 2012 but still has some areas that need finishing. The house is 105m^2,two storey and detached. The windows are approximately 70% south facing and their area is equivalent to around 30% of the floor area. By comparison, he says a developer house would be closer to 10-15%. The large windows provide more all year round solar gain, though it is important to incorporate methods to avoid excess summer solar gains. Even before external shading and curtains have been fitted the temperature of David’s house has not exceeded 24.5°. When this shading has been installed it is likely that it will be 2-3 degrees cooler in summer heatwaves.

Reclaimed slates and rooflights on northern roof

The house is of concrete construction, with concrete floors and concrete block partition walls, which has the effect that the summer temperatures are not as extreme as they would be in a lightweight construction house.

“I was keen to go down the thermal mass route because it’s a way of making fuller utilisation of passive solar energy, which is almost free if you are building a new house….Passive solar is something which everybody should be using long before they consider using solar water heating or solar photovoltaics.”

Getting things built and materials supplied to the standard specified was the greatest challenge

David was surprised that failures in materials on his build were greater than failures in workmanship. Particularly he felt let down by the suppliers of three insulation materials, which didn’t meet the specification and which caused problems as a result.

Despite being on site at least once every day he wasn’t able to avert particularly inept tradesmen from messing up laying the stone floor tiles.

The living room stone floor was ground down by 1mm and the surface repolished after the tradesmen left. This picture is after the remedial works were carried out.

The granite kitchen floor was left uneven by the tradesmen. Being too hard to grind down, it has had to be left unchanged.

David says that friends and colleagues of his from Europe who spend time watching building sites operating in the UK, come to the same conclusion as him – that things just don’t operate smoothly.

“They should operate better than that and systems ought to be put in place that mean that they can operate better than that which would make life much easier for self-builders, because self-builders don’t always have a construction background and therefore they need to rely sometimes on building tradesmen doing things right. And my experience showed that in one or two cases building tradesmen didn’t know how to do it right and I was aware that they were making mistakes, but the average self-builder might not be aware.”

Find out more

Visit the Energy Advisory Associates website

Keep an eye out for David’s book about his self build

Learn about The Autonomous House – a project which David was instrumental in

Transcript

Download a transcript of the interview with David Olivier.

Property company fined for false advertising

The Bournemouth Echo reports on a case where a property developer has been fined after falsely claiming that their properties at Pennsylvania Heights, Portland, were built to certified Passivhaus standard.

This has got Ben Adam-Smith thinking for the following reasons:
1. Even though they failed to reach the standard, they still wanted the prestige associated with it
2. Isn’t it good that you can really define what a Passivhaus is
3. Doesn’t this all mean that in the future there will be added value if you can prove that you have a certified Passivhaus?
You can read the article here.

Regen Media opportunities

At Regen Media we’re always seeing new opportunities arise and are looking for more great people to help with various different projects. Perhaps you’re someone who works in construction, you’re a Passivhaus architect, builder etc. with a passion for teaching. Or perhaps you’re the reverse and are a teacher in education that’s wanting to do something around climate change, around building better homes. Or maybe even you work in TV, radio or write for a newspaper but this is where your passion really lies. If this is sounding like you, then we’d love you to get in touch!

The Hub update

There is so much that can be learned from visiting building sites, and The Hub is all about making that on-site experience available to a wider audience. We’ve been fortunate enough at The Hub to follow the Long Barrow Passivhaus project and our latest video takes us up to the raft foundation stage.
Each month we’re adding a new module too. In January we were looking at self build loans, how they work, cashflow, making sure you don’t overspend etc.
We also have a community element, with a Facebook group for Hub members to share advice, tips and answer questions.

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February 3, 2016
HPH078 : Externally Insulating a Bungalow with Straw Bales – with John Butler
John Butler tells the story of how he retrofitted a bungalow to be more energy efficient. Having carried out a lot of the work himself, he also shares what he’s learnt about airtightness and overheating.

Interview with John Butler

Although it had been John and Anna’s dream to build their own house, they found themselves muscled out of the local market for plots by builders.

John had attended a straw bale building course and was struck by some of the slides which showed a bungalow in the Czech Republic which had been wrapped in straw bales on the outside. With plenty of bungalows in the local area with poor energy efficiency their focus shifted away from the idea of building from scratch and instead towards searching for a property to retrofit and extend.

Straw was Always Part of the Plan, Whether for a New Build or a Retrofit

Having been on straw bale building courses and volunteering on builds, John felt that straw was a fun material and enjoyed the atmosphere on site from the types of people it also attracted. The more involved he got the more he realised its sustainability potential; being well insulating, breathable, accessible and a waste product from agriculture.

Gaps Need to be Eliminated Between the Bales and the Original Walls When Wrapping the Building Externally

Firstly the walls were levelled with clay to ensure no rodents or insects were able to crawl through the channels. Gaps would also potentially allow air flows which would bypass the insulation. Once the walls were level they were able to create a firm connection for clamping the bales onto.

Foundations Were Needed for the Bale Walls

As John was trying to avoid using concrete foundations they dug down and used gravel, compacting a layer, before adding further layers by the same method and finally finishing up with a strip of limecrete. The bales themselves were elevated from the ground by an insulated plinth brick wall to ensure that any moisture or leaks would run through the bales and drain out through the foundations.

Airtightness Should be Planned From the Beginning

Unfortunately airtightness was something John only became aware of later in his project! He discovered the importance of airtightness for energy efficiency through following others on social media, and then tried to incorporate it into the build. It was easier to do this in the extension, but in the bungalow they also managed to use tapes around the windows and are hoping that the plaster skim will keep it airtight. An air test they carried out before completing the finishes showed the weak areas and where they needed to go back and make adjustments.

John admits that with hindsight he would have planned better and carried out more research before starting, to ensure he had a really good airtightness system. He notes though that he would be interested in finding out about the sustainability credentials of the tapes and membranes themselves.

Initial Plans Were Designed and Drawn in Sketchup

Once John and Anna had thought about the spaces they were looking for in their new home, John drew their ideas in Sketchup before sending them to their consultant in the Czech Republic for suggestions.

A Vaulted Ceiling in the Living Area Helped Compensate for the Loss of Height From Insulating the Original Floor Slab

One option would have been to excavate the original concrete slab, however with the waste materials being sent to landfill and the risks of excavating within an existing building, it probably would have been wise to have knocked the bungalow down.

Instead, the chosen option was to use wood fibre insulation boards on top. This does mean however that they’ve not managed to get enough insulation in the floor, without digging the concrete slab out, for it to reach Passivhaus standard.

Solar Tubes and Roof Lights Provide Welcome Additional Light, But Have Their Drawbacks

The solar tubes have been effective in providing additional light without structurally taking up much roof space. In summer however, they have found that the direct sunlight beaming through their various roof lights has resulted in overheating of the spaces. This is something they had prepared for on the living room’s two large roof lights and installed external shading, however this does mean that using the shutters blocks the light from coming in.

Again, with hindsight John would have planned for this and used the PHPP (Passive House Planning Package). It is an annoyance for John that they had planned for saving energy and not being cold in the winter, but now have the opposite problem of overheating in the summer.

Self Building Has Been Satisfying But Draining

While John finds it very satisfying to point at the work he has done himself, he readily admits that it has also been all encompassing and draining. He recommends having people to help out at least with elements of the build to provide stimulation and motivation.

He sees self building as a balancing act, of paying people to do the labour meaning you could get back to work earlier, against the potential financial savings and satisfaction of doing the work himself.

The result is a house where he and Anna are enjoying their new light, warm and comfortable spaces.

Find Out More

Visit John Butler’s blog on his self build

Follow John Butler on Twitter

Transcript

Download a transcript of the interview with John Butler.

The Future of Housing – Premiere!

The date is set for the first screening of our documentary The Future of Housing – And How Airtightness Can Help.

This project was crowdfunded on kickstarter earlier in the year and on Thursday 4th December 2014 you can see what we’ve been up to!

The venue will be the Mildmay Community Centre, which was the UK’s first non-domestic retrofit to the Passivhaus standard. So there’s a building to check out too!

We hope you are able to join us for what will be a special evening. Capacity is limited, so get your ticket now.

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November 12, 2014
HPH064 : Should You Expect Overheating in a Passivhaus? – with Ken Levenson from 475 High Performance Building Supply
Ken Levenson from 475 High Performance Building Supply explains what overheating is, why it happens and how to deal with it.

Interview with Ken Levenson

Ken Levenson ran his own architecture firm in Brooklyn, New York, for 20 years. As he focused more and more on low carbon solutions – and eventually Passivhaus – he became aware that it was very difficult to get hold of appropriate materials. That’s when he decided to set up online store 475 High Performance Building Supply.

We Each Experience Overheating at Slightly Different Temperatures

In general terms, overheating is where the internal temperature of a building rises to such a point that it causes discomfort for the occupants. Therefore, with different people that comfort threshold is likely to be at different temperatures.

The Passive House Institute has a more specific and technical definition of overheating: no more than 10% of the hours of a day can be above 25º Centigrade (77º Fahrenheit).

Overheating of Buildings Has Happened Throughout History

Most people have experienced overheating in buildings at some point in the summer months.

What’s unique to Passivhaus is identifying overheating as a problem and defining it, in order to address it successfully.

There Are Several Reasons a Building Might Overheat

On hot days if there are uncontrolled solar heat gains a space can quickly warm to uncomfortable temperatures.

Ken continues: “Another way is just from the thermal envelope from an insulation point of view. If you have a very hot temperature the heat transfer through the enclosure is going to occur coming into the structure just like it would be in the winter time going in the other direction.”

Internal Heat Gains Are a Huge Liability in the Summer Months

In a Passivhaus internal heat gains – the heat from our bodies, equipment, lights, cooking, etc. – are used to great benefit in the winter months.

However, in the summer they are a constant heat source that can significantly contribute to overheating if the space is at the borderline.

When a Passivhaus is being designed with the Passive House Planning Package (PHPP) internal gains are being taken into account and a balance is being struck so that the risk of overheating is being kept to a tolerable level.

Occupants Can Often Prevent Overheating

Some designs might use night time cooling as part of the strategy to avoid overheating. This requires the occupant to flush the air in the house by opening windows at night time when it will be cooler outside.

Closing external window shades is another strategy that actively involves the occupant.

Ken says: “If the occupants aren’t behaving per the design and the PHPP they’ll be experiencing much greater incidences of overheating.”

Once Overheating has Occurred, Active Cooling May Be Necessary

If the temperature outside is hotter than it is indoors, there is no way to regain a comfortable temperature than by actively cooling (air conditioning) the space.

Prevention is therefore better than treating the problem. This can be done passively with architectural elements such as overhangs and awnings or with external blinds.

It’s Easier to Control Solar Heat Gain on the Southern Exposure (in the Northern Hemisphere)

Ken says that as windows are added to the east and west facades, solar heat gains become more difficult to control than on the southern exposure.

This doesn’t mean eliminating windows on these aspects of the building, just paying close attention to how they are shaded.

Use the BBQ for Cooking in the Summer!

Having good indirect daylighting allows the occupant to keep out direct solar gains in the height of summer.

Ken has previously advised clients to be much more cognisant of their incidental heat gains. This entails switching off lights and as many electronic gadgets as possible, and avoiding activities such as baking – instead opting to use the barbecue!

Passivhaus Buildings Have the Ability to Stay Cool in a Blackout

When so much of the USA is reliant on air conditioning, a Passivhaus has extra resilience.

Ken recalls that when there was a blackout in Virginia a couple of years ago most houses quickly became unoccupiable due to the heat. The Passivhaus in the neighbourhood, however, was not only habitable but comfortable for many days.

Passivhaus May be More About Cooling in the Future

When a building is air conditioned the heat is removed and put outside. In cities, therefore, as more people require active cooling the urban heat island effect only gets worse.

Ken says: “It’s going to be interesting to see how this evolves. Passivhaus really started from a cold climate heating genesis, beginning, but really what I think will drive the conversation, the science, and how we’re approaching it is going to be cooling dominated.”

A Heat Pump is Very Handy in a Climate Like New York

Many Passivhauses in New York are being heated by air source heat pumps. However, this simple technology is very useful in the extremes of summer for cooling too.

Find Out More

475 High Performance Building Supply

Follow Ken Levenson on Twitter

Transcript

Download a transcript of the interview with Ken Levenson.

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July 30, 2014