Tag: comfort

HPH362: An easier way to build a certified Passivhaus – with Clare and Ross Booth

Clare and Ross Booth from Coldwells Build share details of their prefabricated, turnkey Passivhaus designs that aim to simplify the delivery of high performance homes in Scotland.

Interview with Clare and Ross Booth

Ross and Clare Booth are the founders and directors of Coldwells Build in Aberdeenshire, Scotland. Ross started out as a joiner and construction worker while Clare has a background in journalism and communication. Their construction company has delivered a number of bespoke housing projects and is now launching a range of contemporary, turnkey Passivhaus designs which will be sold at a fixed price and prefabricated off site.

This episode is set against a backdrop of potential change to the building regulations in Scotland.

Help keep the Scottish Passivhaus equivalent on track

Last year the Scottish Government announced plans to introduce new regulations for all new build housing to meet a ‘Scottish equivalent to the Passivhaus standard’.

Whilst this was exciting, the devil is in the detail and this is currently being fleshed out in a consultation about the proposal. Unfortunately there are signs that it may be watered down, which means we need to have our say and get it back on track. So please take the time to respond. The Passivhaus Trust has made it easy to understand what detail is lacking, so check out their guidance to help you play your part in the consultation.

The ‘Passivhaus equivalent’ doesn’t need to reinvent the wheel

The Passivhaus standard works so well because it is a holistic approach which addresses building physics, and there are quality assurance processes built in so that we get the results we anticipate.

Clare says that adopting the Scottish equivalent to the Passivhaus standard could have a profound effect on future homes across Scotland, and help the Government reach its net zero emissions target set for 2045.

Upskilling the workforce is essential

Clare and Ross believe that for Scotland to achieve higher building standards there is a great need to provide additional training for construction workers. Ross shares an example from his own experience as a joiner when he installed an airtightness membrane but didn’t really understand what it was doing or the attention to detail required when carrying out this work.

Clare and Ross have both upskilled as part of their professional development

While networking Clare discovered that some free Passivhaus tradesperson training was available and sent the whole team to Glasgow to attend. Ross admits that he was sceptical at first but was completely converted by the end of the training. This was Government funded and provided by BEST (Built Environment Smarter Transformation) who are working to decarbonise the built environment through upskilling and educating people in the construction industry.

Clare also attended a number of satellite events at the COP26 global climate change summit in 2021. Amongst her findings was that most homes still rely on oil and gas for heating which is contributing to nearly a fifth of the UK’s carbon emissions, the UK has some of the worst insulated housing stock across Europe, and that the performance gap currently sits at a staggering 60% in some cases.

A ‘bespoke’ home project is not a simple process

Having worked with numerous clients on one-off bespoke projects, Clare and Ross have identified key pain-points in the self build journey. For example, it can be difficult to design projects within budget and so clients need to go back and forth between their designer and the construction team until they have refined plans. There’s also fatigue from the estimated 3000 decisions that are needed to realise a new home. Then add in the unpredictability of the build itself, which may be subject to bad weather delays and noise complaints from neighbours.

Building off-site in a workshop is a lot more predictable

In an attempt to address some of the challenges of self build and streamline the process for their clients Clare and Ross decided to create a collection of predesigned homes that they would sell for a fixed price. Not only would these be beautiful contemporary homes but there would be a set number of materials and colour choices, making it easier for clients to choose. Another big change would be taking advantage of modern methods of construction by prefabricating these houses off site in a workshop. This also has the potential to increase quality as everyone can be trained in specific roles.

By increasing the insulation specification, their Passivhaus designs can work anywhere in Scotland

Over the last two and a half years Ross and Clare have been working with John Gilbert Architects to produce six ready-to-go Passivhaus designs.

As Passivhaus is site specific one challenge they faced was how a standard design could work on any site. The solution was to over-egg the insulation slightly so that the solar gains were not as critical.

We’ve got quite a chunky wall and roof system. And we’ve tested the house on PHPP on a coastal exposed site in the North East of Scotland, and we’ve tried it in every orientation, and it’s passed.

A visualisation of one of the ready-to-go Passivhaus designs

A building plot is essential to start the process

Although you might be tempted by the designs you need to have secured a building plot before you can engage with Coldwells Build. After selecting a house design they will check that it works for your budget, before moving on to a concept agreement.

At this point it is possible to make a few internal layout changes, providing that they don’t lead to structural changes. The team will then prepare a site plan and get everything cost checked and prepared for planning permission.

Once planning has been approved, Coldwells Build will create a preliminary building agreement and you can start looking at the internal finishes and kitchen designs. They will get the cost as accurate as possible at this stage and then the architect will submit for a building warrant. Once this has been approved, the client can sign a building contract, and the prefabrication will begin.

Assembly ‘on site’ will take a matter of days

Ross says that prefabricating the home would start within three months of having a building contract signed. Whilst the prefabrication is happening, the groundworks team can be on site, preparing the foundations, substructure and floor slab. Once the timber frame is delivered to site, it can be made wind, water and airtight within days. The cladding will be pre-installed and the wall panels and roof panels pre-insulated. The airtightness membranes will be pre-fitted, and only the joints will need to be taped on site. It is a quick turnaround from arriving on site.

The costs will be fixed and known upfront

Clare says that the average price for their four-bedroom turnkey design will be around £420,000. There is also a ‘You Build’ option, which gives you a completed shell that you would then have to fit out, and this is currently around £220,000. Again this is for a certified Passivhaus, which is core to their offering.

The Passivhaus collection will be launched next month but there is already a lot of interest and they even have a waiting list! So it’s an exciting time for Coldwells Build. They are currently working with their first customer which they will use as a test run and to check all their processes, before taking on more customers. Initially they are going to be limiting themselves to producing six houses per year. Clare explains that the most important thing is not to overload themselves and therefore ensure the quality of their homes.

Find out more

Visit the website of Coldwells Build

Transcript

Download a transcript of this episode

Please connect with us

Subscribe, rate and review us on Apple Podcasts

Like our Facebook page

October 9, 2024
HPH322 : An EnerPHit standard retrofit of a Victorian mid terrace home – with Guy Hargreaves

Homeowner Guy Hargreaves reflects on adapting and expanding his Victorian mid terrace home, retrofitting the whole building to EnerPHit standard.

Interview with Guy Hargreaves

Initially we chatted with Guy Hargreaves (episode 297) about his aspirations for upgrading his period property for energy efficiency, comfort and to future-proof it for a less hospitable climate. He had gone through the design process and gained planning consent to adapt and extend the property, and targeted Passivhaus standard (largely helped by the form or shape of the building) for the project.

In this episode Guy returns after the renovation and reflects on the construction stage as well describing what the house has been like to live in.

Guy has been fantastic in sharing the journey in our membership community, The Hub.

Go behind the scenes of this deep retrofit. Get access to our in-depth video case study in The Hub

Access issues meant a lot of manual labour

The project began in February 2021 with the strip-out but initially everything had to be removed through the front door! As the one-way street was narrow construction waste had to be dealt with immediately, so it was placed into the back of a truck, driven to the builders’ yard and sorted there.

Access improved after a ‘win win’ arrangement

As time went by, Guy managed to negotiate access through a private car park at the rear (on an adjacent road). In return he offered to resurface the car park at the end of the process, fix the lights and replace the fence.

Before the renovation

Visualisation of the proposed scheme (at the rear)

New foundations were prepared for the extension

At the rear of the property a small lean-to extension was demolished and fresh foundations were dug for the new extension which would be the width of the property. A digger was craned into the garden from the car park to make the excavation work easier.

Tonnes of soil was removed to prepare for the new foundation.

Then the concrete went in, followed by a layer of insulation and a floating concrete slab.

Steels help open up the old house, but were not necessary for the retrofit

A key element of the brief was to open up the space and so a couple of walls on the ground floor had to go. Structural steels spanning the width of the house were added to take the loads from above.

Some steels already existed in the house from previous renovations but these needed to be replaced.

A contingency is always essential on a retrofit

It is impossible to predict everything that may crop up during a retrofit which is why a healthy contingency fund is always required. One ‘nasty’ on this project was the condition of the bay.

Although a homeowner’s survey was conducted when the property was purchased it did not flag up any issues. However as the building was stripped back cracks around the windows and crumbling brickwork were revealed, and it became clear that a structural engineer would have to take a closer look.

The outcome was that the bay needed to be rebuilt at ground level with some underpinning necessary at basement level.

Insulation and airtightness strategies change around the building

With a mixture of new and old, brick and timber, combined with planning constraints the technical design utilises several difficult wall build-ups. For example, at the front of the property the appearance had to be preserved and so an internal wall insulation strategy was necessary. This breathable build-up has several layers including a diathonite plaster (the airtightness layer), wood fibre board and a lime based plaster.

The ceiling height in the basement was not as generous as the floors above but removing a 75mm screed layer gave them a bit of wiggle room to add 40mm of rigid insulation.

Up in the attic room rigid insulation was used in the roof. And at the back of the house softer wool batts were filled the timber frame.

Larsen truss built on site for rear extension

The new extension is timber frame and uses a twin stud Larsen truss (300mm) to create a decent size cavity for the required insulation. Cutting and erecting it on site is a simple and cost effective route to achieve high performance.

The room at the top of the house was expanded

A previous owner had converted the loft but the sloping ceilings made it slightly awkward space so Guy planned to open it up on the garden side (south side), which also affords the best view in the house.

The skylights before the renovation

Guy understood the overheating risk of the dormer room

That whole south side we glazed in a rather aggressive and somewhat controversial scheme that is going to be a work in progress over time because that dormer is the top of the house… The heat in the house tends to rise into the dormer and add to the solar gain.

External blinds will be installed if ever needed

While over-glazing will lead to overheating Guy did not have his eyes closed. Instead he made sure that there was a strong back-up plan. So there were plenty of window ventilation options as well a reverse cycle heat pump, which can be used for cooling. However, if the temperature becomes unbearable then the ultimate solution will be external shading.

Guy stepped in as quality control

Much like Mike Coe’s experience in Portree, Guy decided to monitor quality.

He was on site every day checking how the airtightness layer was coming together, highlighting potential weak spots.

Airtightness became a personal challenge

I knew that we would get the insulation right. But I had absolutely no idea that we would get the airtightness right. And the airtightness, it’s like a stop go thing. It’s like blowing up a balloon. If there’s a hole in it you will get found out.

The biggest worry would be areas where the airtightness layer gets hidden by the construction.

Interim airtightness tests highlighted areas that needed attention

Guys likens airtightness to ‘compliance’ in the corporate world. He suggests that those in charge of the results should almost be separate from those doing the work.

Pressurising the fabric of the house and using smoke pens to identify leaks was essential to eliminating draughts and improving airtightness.

Airtightness is really about chasing down your problems.

Pausing construction to perfect the airtightness is not realistic

In an ideal world the required airtightness would be achieved before any finishing work was carried out.

With a team of builders on site it becomes increasingly difficult to address small airtightness issues without progressing work elsewhere in the building.

Delays in ordering increased pressure

With supply chain issues the sequencing on this project added another layer of complexity. Lead times could change overnight.

Architects’ contract administration a good call

One of the more valuable things we did was to engage with my architect in an administration contract, which included a fortnightly visit on site, and that kept a level of professional focus on what was needed, what was coming up, where the timing was, what was being realistic, etc.

The Passivhaus standard became a step too far

EnerPHit is the retrofit standard for a reason. It is hard to modernise existing buildings and this is why it’s a slightly less stringent target.

Although Guy held onto the goal of achieving the Passivhaus standard target of 0.6 air changes per hour (@ 50 Pa) until the ‘grim death’ there came a point where he realised it was too much of a stretch.

Work in the basement apartment had been halted to focus on the main house so that Guy and Susan could move back in as soon as possible.

So the first ‘official’ airtightness test of the main house was after they had moved back in (March 2022). At this point it became harder to carry out remedial work.

And an airtightness test for the basement was still needed for an overall result (which came a few weeks later).

The final result for the whole house was 0.95 (ACH @ 50 Pa).

Knowing the ‘Hurculean’ effort that went in Guy is immensely proud.

That’s what the EnerPHit standard is about… recognising the almost exponential effort in getting from 1 ACH to 0.6 ACH (@ 50 Pa) in a property that’s already built.

Comfort tops the benefits

Guy laughs about being able to wear shorts and a t-shirt almost all year round!

He also points out how quiet and still the house is.

With an all electric house the bills are likely to be 1/5 of what they were before, but clearly there has been a massive upfront investment.

Solar PV is the only missing element!

In some respects the people I’m feeling most envious about today are those who have 10 kilowatts of solar PV on their roofs.

With an efficient heat pump providing heating and cooling for the house as well as the hot water, Guy has got nearly everything for the resilience and future-proofing he wanted.

However, there were not many good options for a solar installation. The flat roof at the top of the house was the obvious one but it only had a couple of kilowatts potential.

I didn’t think that that was worth the trouble, to be honest. But given everything else that we were doing, it was just probably the straw that broke the camel’s back.

Good communication and a stable relationship with your builder is vital

Having been through building processes before Guy has been reminded how important it is to have a stable relationship with your builder. The key to this is staying calm and talking through any challenges.

Changing your builder is a vastly complicated process and it’s made even more so when you’re halfway through a Passivhaus. And you wouldn’t find another builder to want to take it on. So having a strong relationship with the builder is super important.

There is an appetite for retrofit in the UK

Guy has already opened the doors of his home to local community groups interested in retrofit.

There is an enormous appetite in Oxford, and I think probably UK wide, for all or some or most or half of the things that we’ve done to our property.

Watch our documentary of the Kinver project in The Hub

Find out more

Check out part 1 – our interview with Guy before construction began

Visit the website of Eco Design Consultants

Transcript

Download a transcript of this episode.

Passivhaus Open Days

Twice a year Passivhaus dwellers open up their homes for you to have a look around, experience the level of comfort, gain insights into best practice and ask any questions.

Search for what events are taking place near you.

Please connect with us

Subscribe, rate and review us on Apple Podcasts

Follow Ben Adam-Smith on Bluesky

November 2, 2022
HPH271 : Common questions about the Passivhaus standard – with Ben Adam-Smith
Ben Adam-Smith shares some of the questions that got asked about the Passivhaus standard during a question and answer session at the National Self Build & Renovation Centre.

Passivhaus workshops

Twice a year the National Self Build & Renovation Centre (NSBRC) hold a Passivhaus workshop in association with the Passivhaus Trust. This explains everything from the origins and principles of the standard to the benefits and how you might go about building your own Passivhaus.

The event is hosted by Passivhaus Trust members who are also exhibitors at the NSBRC.

Chairing the Q & A was Green Building Store’s Director Chris Herring

The panel was slightly different each day but included Alan Budden from Eco Design Consultants, Jae Cotterell and Anna Carton from Passivhaus Homes, Paul Smith from Green Building Store, Jasper Meade from PYC Insulation, Robin Miller from Beco Wallform, Clarissa Youden and Michael Hunt Total Home Environment and self-builder Juraj Mikurcik.

Before the Q & A began, Chris Herring asked the panel to give their top tip for building to Passivhaus standard.
1. Put Passivhaus on the brief from day one
2. Take a fabric first approach, investing your money in achieving Passivhaus standard before you even think about renewables
3. Get buy in from all your team
4. Make sure you hire someone with Passivhaus experience
5. Don’t skip steps, like missing out the PHPP modelling
6. Get the form factor down
7. Keep it simple (and it will be easier and cheaper to achieve the Passivhaus standard)
8. Design out the overheating risk
A slide on why you don’t want to cut corners

How do you heat a Passivhaus?

There was no definitive answer for this.

But first, a variation…

“I’ve heard you don’t really need heating in a Passivhaus. Is that true?”

This is a bit easier. Yes, you do need additional heat in a Passivhaus but it will only be a small amount of heat.

If you’re going with renewables, an air source heat pump can be a good solution. Ground source heat pumps are generally overkill and therefore unlikely to be used.

My own Passivhaus uses a gas boiler and although these are clearly on the way out, the gas main may still exist in some capacity in the future. So our logic was to connect now and then we can always dump that connection at a later date. And it’s much easier to do this than trying to connect at a later date. It’s also useful for resale purposes.

Some of the panel suggested, as the grid decarbonises, that electric is the way to go. Jasper Meade talked about building their Passivhaus office with no heating at all and testing it for a couple of years. With a couple of electric heaters downstairs the whole building quickly reaches temperature in winter.

Alan Budden followed a similar logic, saying that electric panel heaters could be good. And they’re portable too.

The stove at The Deerings

What do you think about having a wood burning stove in a Passivhaus?

While this is possible, it’s a good question to ask why you want this. Is it because all your other houses have had one?! Maybe you’ve been huddled around the fire in the winter. Well the experience of living in a Passivhaus is going to be quite different.

The other thing to remember is, no matter how sealed the system, when you add your fuel the stoves will give off particulates. So there are health risks attached.

But if you do still want a wood-burner (perhaps you have your own supply of wood) make sure it has its own air supply.

Is thermal mass important in a Passivhaus?

The panel agreed that having some thermal storage capacity was a good idea, but it doesn’t have to be a lot. This has the effect of just smoothing out the temperature, particularly in summer.

And interestingly, some build systems might have more thermal mass than you think. While concrete is often cited, Jae Cotterell talked about the PH15 timber frame system having significant thermal mass in the form of the cellulose insulation!

What is the value of certification?

This is about quality assurance and is particularly important when your team has limited experience of achieving Passivhaus standard.

If a company has built lots of certified units before, they probably could deliver a Passivhaus with little trouble and the certification may be less important. However, if hiring someone with less experience, following the principles will not necessarily get you to Passivhaus standard.

So certification may just seem like a badge but there is a whole process behind it.

The other aspect to bear in mind is resale. Those looking to buy a Passivhaus are likely to want a certified property rather than taking homeowner’s word that they’ve built a Passivhaus.

It’s also worth remembering that you can get certification at a later date; just make sure you gather all the necessary documentation at the time of the design and build.

Can you make a Victorian house into a Passivhaus?

Yes, this is entirely possible (such as Tom Pakenham’s retrofit).

However, it’s not straightforward, you’re making the building do something it wasn’t designed to do and it won’t be cheap.

Even the Passivhaus retrofit standard EnerPHit is still a challenge. It’s slightly less stringent but still demanding.

We’ve covered various different retrofits on the podcast including Harry Paticas’s phased retrofit of a town house.

Harry Paticas and his son in their retrofitted home

We’ve got a plot, what are the first steps to designing a Passivhaus?
- Put it on your brief and go in search of professionals who have done it before (check that someone on the team is a certified Passivhaus designer).
- Read the guidance on the Passivhaus Trust website.
- Visit Passivhaus properties as part of the International Passivhaus Open Days. Quiz the owners about their own experience and the team they hired.
- Get familiar with the requirements of the Passivhaus standard so that you can make good decisions (and avoid complicating it and adding extra costs).
The PH15 system from Passivhaus Homes

Does the Passivhaus standard take you down a timber frame route?

Passivhaus can be achieved with any build system. You could make an argument that insulated concrete formwork (ICF) makes the airtightness easy while a masonry approach involves putting together a big jigsaw… but fundamentally you can reach Passivhaus standard with any construction system.

But the choice of build system comes down to personal preference and takes into account a number of factors such as cost, ecological criteria, ease of assembly, and so on.

When it comes to planning, how easy is it to adjust the orientation of a house?

As with anything connected to UK planning, it can boil down to the local authority. Some are better than others!

However, most authorities can see the benefit of having more Passivhaus buildings and understand the need to optimise the orientation.

Find out more

The National Self Build & Renovation Centre

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

Like our Facebook page

Follow us on Twitter
November 28, 2019
HPH247 : Two radical retrofits that use an internal wall insulation strategy – with Bill Butcher

Bill Butcher from Green Building Company, the construction division of Green Building Store, explains how they tackled two radical retrofit projects in West Yorkshire. Each took a ‘whole house’ fabric first approach in order to improve comfort levels and reduce the heating bills.

Having been Passivhaus pioneers in the UK with their Denby Dale project, the building team at Green Building Company has kept honing their approach.

There was Golcar new build project and Stirley Community Farm retrofit. Now we look at two of their radical retrofit projects, Cumberworth and Lower Royd, and how they embrace the same philosophy but still require bespoke solutions.

Cumberworth retrofit after the work was completed

Cumberworth radical retrofit

Initially this was part barn conversion and part 1990s extension, so there needed to be two different strategies for this project.

The existing property was hard to heat

The owners were spending £3,500 a year on LPG trying to keep this 150m2 property warm but they were still cold!

A whole house ‘fabric first’ strategy was adopted

In order to make the house more comfortable and reduce heating bills they embarked on a deep retrofit. This embraced the Passivhaus methodology of making the house draught free, increasing the levels of insulation, reducing thermal bridging and introducing mechanical ventilation with heat recovery.

The designs were modelled in the Passive House Planning Package (PHPP).

Insulating internally maintained the natural stone facade

While a lot of retrofits use external wall insulation, there are a few reasons why they didn’t. Cumberworth is at the top of the Pennines and it is exposed to a lot of moisture. The natural stone works well in these parts.

Bill continues: “To build in any other way is totally out of character for this region. And that’s what the customer wants.”

The three moisture risks had to be addressed

The moisture risk depends on the wall build-up. The ex-barn wall had two stone leaves which were filled with rubble! Being a Victorian barn it was also susceptible to rising damp because there was no damp proof course.

In this high exposure region on the Pennines rain driven damp through the porous stone was another risk.

The third moisture risk is interstitial condensation which is the condensation of internal moist air reaching the dew point where it turns to water as it meets a cold wall.

This section of the building was insulated was a product called TecTem, which is vapour open and breathes like the original building would have done.

WUFI was used to model the moisture risks

A German software package called WUFI was used to look at the moisture risks. To increase accuracy it requires a lot of information first.

Bills gives a few examples: “It takes into account where you are, the orientation of the wall – obviously a West wall up here is in more danger than the East wall because most of our rain comes from the West – the rising damp, the type of stone it is, which quarry it’s from, the mortar joints and so forth, and then obviously the insulation.”

Moisture sensors in the walls help monitor the situation and allow Bill to assess the accuracy of the program. “I might say that all of the buildings are performing fine.”

Insulating the extension was simpler

As the 1990s part of the Cumberworth project is a cavity wall construction it should be less susceptible to rain-driven damp. And it’s got a damp proof course which should deal with rising damp.

A ground source heat pump is the heat source

For a new build Passivhaus the energy demand would be so low that underfloor heating would not be appropriate. In a retrofit situation it becomes more relevant.

Also the clients had a field in front of the house which they were keen to use for a ground source heat pump.

Bill explains: “Air source and ground source heat pumps work most efficiently at delivering 35C water, hot water if you like, for your central heating system. And that suits underfloor heating more than radiators. That then informs how you do the floor. Because we don’t want to be heating up masses of concrete in a floor because of the slow cooling and heating – it doesn’t respond. “

So it’s only 75mm of heating screed on top of the insulation.

The insulation follows the line of the roof

As with most of Green Building Company’s retrofit projects they have gone for a cathedral roof. This means the insulation is within the structural timber roof and that the loft space is inside the thermal envelope.

Bill says: ” What we tend to end up doing is having a studwork parallel with our rafters. So we end up with insulation between the rafters, insulation again, and then within the studwork which is between the purlins more insulation. So, we would use more rigid bats between the rafters – a mineral wool in our case – and the studwork, and then just ordinary loft fibreglass insulation between.”

MVHR duct runs were down corridors

As this is a low energy retrofit a mechanical ventilation with heat recovery was specified. It goes without saying that these are fairly intrusive, requiring a plant room for the unit and ducting around the house.

While a new build Passivhaus might use posijoists in the intermediate floor, in a retrofit situation you have to come up with other solutions.

Bill explains that they ran the ducting down the corridor because this was an area where a lower ceiling is not so noticeable.

Vaccuum insulated panels were used around some window reveals

Green Building Store had already supplied outward-opening triple glazed windows to this property five years previously and hence they were keen to keep these!

One challenge they faced was in maintaining the continuity of insulation.

Bill explains: “If you do it [insulation] well in ninety percent of your building, for example, the ten percent becomes very vulnerable to condensation and cold bridging. So, the reveals between the very good wall insulation we were doing, in to the window frame, only allowed for a ten millimetre insulation.”

To maintain that u-value at this thickness they needed to use vacuum insulated panels, custom made to fit!

Lower Royd after retrofit work

Lower Royd radical retrofit

Much like Cumberworth, this project had two different parts. One was a virgin barn and the other was an existing farmhouse that hadn’t been touched since the 1960s. So it was ripe for a retrofit.

A connection to mains gas helped inform the project

Despite it’s fairly remote location Lower Royd had a mains gas connection.

The clients had envisaged using a ground source heat pump to heat the house, but in terms of economics, their money could be better spent on insulation!

Bill comments: “A ground source heat pump may cost you twenty-grand to get into the building as opposed to gas and the standard boiler – and we’re talking about the smallest condensing boiler, off the shelf from your local builder’s merchant – costing, installed, fifteen-hundred, two-grand. You’re better off with that saving of fifteen-grand, say, to be put into your fabric. The cheapest energy is the energy you save.“

And of course this doesn’t rule out changing the heating system to an air source or ground source heat pump further down the line.

A spray-on lime based insulation saved flattening the walls

On the Cumberworth project they used a rigid insulation called TecTem. However, they had to invest a lot of time in flattening the walls to be able to apply it properly. So they were keen to consider other alternatives at Lower Royd.

So they trialled a spray-on internal wall insulation from Italy called Diathonite Evolution.

Not only is it airtight, but it is vapour and capillary open to address any moisture issues.

And being a lime product, it naturally inhibits mould growth.

Airtightness is the most important factor for comfort

Having carried out a few deep retrofits, Bill believes that when it comes to energy and comfort, airtightness is the most important factor. Then insulation comes next.

In fact they may experiment with reducing the insulation levels a little on future projects and look at the impact.

Find out more

Visit the website of Green Building Store

Follow Green Building Store on Twitter

Follow Bill Butcher on Twitter

Transcript

Download a transcript of the interview with Bill Butcher.

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

Like our Facebook page

Follow us on Twitter

April 24, 2019

HPH191 : Key decisions that impact on the sustainability of a house build – with Lloyd Alter from TreeHugger

Lloyd Alter from TreeHugger shares his advice on what we should be prioritising as 21^st century self-builders.

Interview with Lloyd Alter

We catch up again with Lloyd Alter, whose work as an architect and a real estate developer led to his interest in modern building methods. He blogs for the website TreeHugger and also teaches sustainable design at Ryerson University in Toronto, Canada. Previously, Lloyd’s talked to us about worldwide trends in green designs.

Don’t measure value in pounds per square foot

Lloyd says that size will be the most important decision about a house build because so much relates to it. While building small may be preferable for sustainability, he acknowledges there are various problems to overcome.

Some contractors may refuse work on smaller houses, or argue that a bigger house is better value. Lloyd warns against buying more space than you need. A bigger house may cost less per square foot but that is a dangerous criterion for measuring value. He explains, “It will cost you more per unit of area to build smaller but the aggregate, it will still cost you less.” Operating and maintenance costs will also be less with a smaller dwelling.

House size may be dictated by the plot

Re-sale value can force a self-builder into a larger project. Often it’s the land that really has the value, so there’s a judgement to be made about the right sized house for the size of the plot. And Lloyd points out that putting in services costs the same regardless of house size, potentially making it harder to recoup costs on a smaller house.

By-laws can, in some instances, prevent small homes being built. For example, Lloyd explains that some North American municipalities fix minimum square footages to guarantee a minimum tax return.

Balance location with lifestyle

Lloyd recognises the dilemma for self-builders who want to minimise their carbon footprint but can’t afford the expensive land located close to facilities.

Low energy buildings can reduce environmental impact, and changing habits can also mitigate high-energy consumption. Someone Lloyd knows – who lives 9km away from town – cycles, uses a hybrid car when he has to drive, minimises shopping trips and avoids ordering things delivered by truck. Lloyd himself tries to balance his many air miles by cycling and keeping his house at “incredibly low temperatures”.

An independent expert will help you design for sustainability

In a poorly planned house, you pay more for a poor living experience. Lloyd mentions one self-builder who incorrectly fitted insulation and this decision threatened to destroy his house.

For Lloyd, an architect should “help you get to the essentials and put the essentials together in the most efficient, satisfying and beautiful way.” He sees this as directly linked to building sustainably: “The key to sustainability is living with less and the key to living with less is to have it designed properly.”

To choose an architect or builder, Lloyd suggests going to see their work and spending enough time with them to know that you like them, they understand you and that you can understand what they’re saying; clients shouldn’t have to deal with what he calls “Architectese”!

Simplicity should be designed into the house in the first place

So-called “smart homes” are fashionable but Lloyd is wary of unnecessary complexity that adds cost and needs maintenance. “My attitude is I like a dumb home!”, he says, citing the Passivhaus as a good example of this. Using less power means no need for a smart thermostat or a complicated solar panel system connected to the grid. “The house takes care of itself,” he says.

Another reason to keep house design simple is to accommodate changing technology. Low voltage LED bulbs have practically eliminated the problem of lighting load and our technology increasingly runs on low voltage DC wiring. Lloyd envisages future houses solely using DC, so any high voltage electric systems fitted now should be kept accessible.

As different building elements last different lengths of time, Lloyd’s advice is to prepare and keep things simple. “Put as little of it as you need in. Because at some point, you’re going to have to redo it anyway.” Homeowners should be able to access, change or fix any systems in the house:

Element of your property	How long it may last
Land	Forever
Frame of your house	500 years
Cladding	200 years
Windows	100 years
Plumbing	50 years
Electrical	20 years
Mechanical systems	10 years

Fabric first is fairer as well as simpler

Lloyd believes it is unreasonable to simply aim for “net zero carbon”, stating, “We have to use less, period. Even if we’re trying to offset it with energy from sun or wind.” Thus, investment in domestic energy production is another trend that Lloyd mistrusts. Compared to the huge amount of energy used for transport, he describes solar panels on roofs as inconsequential. “We should be going after the big things. And that’s efficiency, not solar panels on the roofs,” he says.

He remarks that policies of domestic generation of electricity disproportionately favour people who have south-facing roofs. Someone without a roof or who can’t afford solar panels will pay more for their electricity, meaning the poor end up paying for the grid. A fairer system in Lloyd’s view would be for everyone to live in houses that are built to a higher standard and use less energy.

Preferred methods of building continue to change

Lloyd teaches a sustainable design course and the content can change every year. Ten years ago, he taught about spray foam that seals and insulates efficiently, but we know now this foam contains unhealthy flame-retardants and some don’t even work below three degrees Celsius. The current insulation trend is for low carbon cellulose, although Lloyd prefers rockwool.

On the subject of new building techniques, Lloyd says, “I’ve become very conservative as I’ve gotten older.” He sees people who want the “latest new thing” demolishing existing houses on highly sought-after plots. This discourages building really good quality houses because “they don’t seem to be building them forever anymore”.

Construction methods can be more suited to specific locations

Building with “brick and block” gives thermal mass, holding heat in the day and releasing it at night. Lloyd says that this principle works well in the high Arizona desert, with hot days and cold nights. In less extreme climates such as the UK it is less effective, and making bricks, concrete and mortar releases a lot of carbon dioxide before construction even begins.

Homes should be comfortable, safe, secure and resilient

A self-build should bring comfort and happiness. Just because it’s environmentally friendly doesn’t mean you have to suffer!

Considering our changing world, Lloyd advises self-builders to prepare for power outages, provide some storage for water and food, and build high enough and not in the middle of a flood plain. He adds that if you have to cycle to get milk, then make sure you can actually do it! “That’s what a home is supposed to be,” he says. “A place of security and comfort. That’s what we should all be striving for.”

Find out more

Visit the website of TreeHugger

Follow Lloyd Alter on Twitter

Transcript

Download a transcript of the interview with Lloyd Alter

Please connect with me

Subscribe, rate and review the podcast in iTunes
Rate and review the podcast on Stitcher
Like our Facebook page
Follow us on Twitter

September 25, 2017

HPH169 : Embracing contemporary vernacular design – with Clare Nash
Clare Nash from Clare Nash Architecture talks about various responses by small developers in the UK and abroad to the challenges of creating modern communities through better design.

Interview with Clare Nash

Clare Nash set up Clare Nash Architecture six years ago. The team operate differently to other architects, working remotely or in co-working spaces and meeting up once a week. Her book, Contemporary Vernacular Design, How British Housing can Rediscover its Soul, naturally followed on from her Masters thesis where she researched the uses of vernacular materials and technologies in modern, sustainable housing in the UK and abroad.

In the past, houses were inherently green

Clare says, “Vernacular [design], I think, doesn’t really exist anymore, apart from in developing countries where people are literally just self-building.” Buildings used to be sustainable and varied in their design, using local materials and low energy out of necessity. She adds, “We seem to have lost all these really good ideas in modern housing design.”

In the UK, there are a few exceptions including Ashley Vale where a group of self-builders actually got hands-on and developed such a strong community that others really want to live there.

Contemporary vernacular design is a hybrid of old and new

Clare likens contemporary vernacular design to being a mixture of the best of the old and the best of the new. She cites an architectural ‘taste test’ that was carried out in Holland, where members of the public, architects and design professionals all found this ‘third way’ preferable to super modern or a pastiche of the old.

The residents Clare interviewed in Europe abroad unanimously liked modern homes, whereas she found people in this country quite suspicious of them. She believes this is because they tend to think of the poor quality housing stock built in the post-war period.

Incorporating good landscaping encourages people to talk to each other

Clare talks about contemporary vernacular design as a way to have mass produced housing that retains a sense of identity through the varied design of the homes and getting the landscaping right.

She cites an example in Holland where a group of architects took inspiration from a Mondrian painting to create different types of good-quality houses dotted around bisecting canals and green spaces. Clare compares how this development felt like home, whereas the new build houses local to her in the UK feel like a toy town, soulless, hence the subtitle of her book.

Faro Architekten project in Biesland, Holland

Another case study in Wales had open-ended gardens that led to a lake at the back where residents got to know each other because they often walked there. The design further encouraged interaction by incorporating a shared garage rather than individual drives.

Great House Farm project in Wales

Only residents really know whether housing design works

As well as interviewing architects, designers, housing associations and property developers, Clare made sure to speak to a good selection of the residents at each housing scheme to find out what actually worked.

While she often heard about teething problems, these resolved themselves and some of the small developers even had the foresight to anticipate and make provision for them. Resident feedback was summarised into four categories:

1) Comfort – is it warm enough and is it light enough?

Clare found the levels of insulation and daylighting were better than building regulations dictate. She comments that it’s really important to have bigger windows because seasonal affected disorder could be caused by being inside so much of the time.

2) Appropriateness – how appropriate is the scheme for the area?

Good design takes into account culture and context (i.e. the surrounding buildings and landscape, local materials and craftspeople). Therefore you need different types of housing for different types of area. Clare gives the example of a Norfolk development where they rejected the aesthetic of individual suburban plots; the site meant the front gardens were south facing and the architects chose to only separate them minimally with green wire fencing. The result was like a barn in a landscape.

3) Sustainability – does the design consider the embodied energy as well as the cost of running the home?

The focus in the UK is to save on energy bills but materials should matter too. Clare found examples such as Sieben Linden in Germany where they built everything out of straw bales and timber frame.

Sieben Linden eco village in Germany

4) Improvement – is the housing an improvement on what is currently built locally?

Clare deliberately sought out developments that she felt did better than the status quo, and found that on the whole residents were really happy with the quality of life afforded by the housing and sense of community. “They were just very happy to live where they lived and they didn’t want to move. Which I think says it all really.”

The current dominant building culture in the UK restricts progress

Clare was really excited to meet some progressive and interesting developers who are trying to do things differently with their residents and the planet in mind, but notes that the existing culture prevents widespread expansion of such practices.

She observes that in the UK six big housebuilders are dominating the landscape and what the edges of our towns and cities look like, adding that everyone she talks to seems equally frustrated with what she calls ‘the standard redbrick box plonked everywhere’. Clare compares this with Europe where individual developments respond to local demand.

European governments regulate development differently

In Sweden, no more than 100 houses can be built by any one developer in any one area, which creates a diversity in housing. And in Vorarlberg in Austria, anyone who owns a piece of land can build on it as long as the design (which can be modern) is considered appropriate for the region.

There are cultural differences on the continent as well. In Germany, people often build together in ‘baugruppen’, and they think long-term so they build very good quality homes typically passed on to the next generation.

UK decision makers are beginning to value ‘community’

Historically, councils have gone with the highest bidder when selling land for housing development, and the big companies can outbid the smaller ones. However, councils are now starting to see that a slightly lower bidder can deliver much higher long-term benefits. For example, mixed-use schemes improve the sense of community, making people want to stay and resulting in less maintenance and increasing the scheme’s longevity.

Gavin Barwell, Minister of State for Housing & Planning, has said that the government is going to make it easier for smaller developers to get land and to start developing. Clare finds this encouraging and hopes it will become easier for self-builders too.

Self-builders need to register their interest

At the moment, planning authorities have to find out if there is a need for self-build land and then if there is, they have to provide it. In some cases it’s proving difficult to actually get councils to follow through, but Clare thinks the housing white paper will help to move things forward, saying: “I think it’s quite exciting times now. I’m really hopeful for the future of housing and house building in Britain.”

Find out more

Visit the website of Clare Nash Architecture

Follow Clare Nash on Twitter

Transcript

Download a transcript of the interview with Clare Nash

Please connect with me
- Subscribe, rate and review the podcast in iTunes
- Rate and review the podcast on Stitcher
- Like our Facebook page
- Follow us on Twitter
March 22, 2017
Encore episode : The Passivhaus standard explained
As Passivhaus Open Days return for another year, we give you the opportunity to hear our interview with Dr Wolfgang Feist from 2012.

Interview with Dr Wolfgang Feist

In the 70s, Dr Feist was working on how to meet the growing demand for energy in the world and found there was huge potential to use energy more efficiently rather than produce more energy. The International Passive House Institute is a research facility that influences construction by showing industry and government what can be done, helping to bring improved components to the market place, and helping affiliate organisations around the world to gain members, to gain knowledge and to make that knowledge available.

The Passivhaus approach addresses financial and environmental issues

The cost of energy has increased to the point that a lot of people now have problems paying their heating bills.

More than 80% of the energy being used in the UK, in the EU, and worldwide comes from fossil fuels. The consequences of this – emitting carbon dioxide into the earth’s atmosphere – means we really need to change the way we use energy and reduce our carbon footprint.

Passivhaus buildings are nearly zero energy buildings; their energy consumption is one tenth of that of conventional buildings. The energy you need is so low that it could be supplied by regional sources of renewable energy anywhere in the world, reducing the need to import and use fossil fuels. This is one of the reasons why the European Commission supports Passivhaus.

The Passivhaus approach delivers very high energy efficiency

The Passivhaus Institute produces tools for architects and engineers to make it easier for them to design such an energy efficient building.

By improving the building’s envelope you reduce the typical energy losses, so that you only need a very low amount of heat or cooling to keep the temperature comfortable.

The Passivhaus standard provides a universal design method for achieving a good indoor environment. Although a Passivhaus in Jakarta looks significantly different from one in Saint Petersburg (as local climate will inform the design), the method for designing these buildings is the same.

An improved building envelope has multiple benefits

As well as reducing the amount of energy you need, a higher quality building envelope:
- makes the building more comfortable
- will last longer
- improves the way we maintain the building in the future
The Passivhaus method doesn’t restrict the building style or type, and you can use any kind of material.

The Passivhaus Trust in the UK offer certification which provides assurance to buyers or sellers of Passivhaus buildings that they have been constructed properly and operate to the Passivhaus standard.

To design a low energy building first identify the services you really need

There are certain considerations that influence the energy balance of a Passivhaus building and so need to be factored into the design:
- Good insulation that avoids thermal bridging
- Airtightness
- Window quality
- Ventilation (required due to the air tightness of the building)
The Passivhaus standard isn’t just for new builds

Retrofitting of existing housing stock is harder. The key is to understand when it’s most efficient to make improvements. For example, if you have to do some maintenance to the roof, that’s the time to improve the insulation. You wouldn’t exchange a window just to save energy, you would upgrade an existing window at the end of its life. If you are going to improve a component then choose the best available because it will be 30-50 years until you do it again.

According to Dr Feist, most buildings in Europe that were built between the 60s and 80s are quite easy to refurbish. Older buildings, some of which may be listed, are a bit more difficult but on-going research means there are a lot of measures that can be taken nonetheless.

Passivhaus isn’t as expensive as you might think

Dr Feist explains cost and benefits of Passivhaus, using an example component. A Passivhaus window that is triple glazed and has a well-insulated frame and airtight window might cost £380 per square metre compared to £300 for a normal window. Although this is a little more expensive, the lifecycle cost of this investment gives a better return than investing the difference in other ways.

Non-financial incentives encourage adoption of the Passivhaus standard

Governments can help create a tolerant environment where innovation is accepted, including offering incentives. In Italy, for example, energy efficient builders are rewarded by being allowed to build on a bigger part of the land.

Dr Feist believes that distributing information on improving efficiency in new construction and in refurbishment of existing buildings is also an important role for governments.

The on-going challenge is to change habits within the construction industry

Scientifically it’s easy to improve energy efficiency, but the construction industry is very conservative. However, Dr Feist remarks that adoption of the Passivhaus standard continues apace because it’s not so different from what they have done in the past, adding, ”they can learn how to do it but they have to decide that they want to learn”.

Find out more

Visit the website of the Passivhaus Institute

Follow Dr Wolfgang Feist on Twitter

Please Connect With Me
- Subscribe, rate and review the podcast in iTunes
- Like our Facebook page
- Follow us on Twitter
November 9, 2016
HPH097 :What Do You Get for Passivhaus Certification? – with Peter Warm from WARM

Peter Warm from WARM: Low Energy Building Practice explains why building to Passivhaus standard is desirable, how certification comes into the equation, and what steps will increase your chances of reaching certification.

Interview with Peter Warm

Peter has been an energy engineer all his working life and is fascinated by high performance buildings. Through his involvement with the AECB he got into Passivhaus certification, and this is now a key service offered at WARM: Low Energy Building Practice.

“Glass Boxes are a Huge Problem”

One of the biggest challenges WARM face is communicating to architects that vast quantities of glazing in a Passivhaus actually create a “solar cooker”. While the glazing is expensive it also creates a problem which will need remedying with the additional cost of solar shading.

“Glass boxes” are effectively huge energy consumers, either for heating or cooling.

Passivhaus Certification is a Form of Training for Designers

Peter thinks of the certification process as a form of training because it gives designers a deeper understanding of how the decisions they make impact on the energy performance of their buildings.

If the designer hasn’t reached the Passivhaus standard before then inevitably there is a learning curve. However, the certification process provides support throughout, in order to iron out any issues before they occur.

For designers that WARM have worked with many times before they will be offered a greatly reduced quote because they need far less hand-holding throughout the process. In these cases, it’s really all about the documentation.

“Passivhaus Certification…It’s Just About Building Buildings Sensibly, Doing it Properly”

Peter suspects that in 20 years time the current quality of a Passivhaus will be the norm for a new build. Although much of the UK construction market is currently lagging far behind in terms of build quality and low energy standards, Peter sees retrofits as being a greater challenge for the future. There needs to be more education about the dangers of getting insulation wrong which – if not done properly – can cause mould, condensation and rot as well which in turn can impact on the occupants’ health.

The Steps to Certification

The Quote – This is based on the plans and sketches, an idea of how long the process is going to take and the level of support the designer is likely to need.

Design Review – It is important to review the designs before planning to look at the impact of things like the form factor (on insulation and airtightness) and fenestration (on solar gains).

Checks Before Going On-Site – WARM will usually do their own PHPP calculations to check thermal bridging, airtightness, heating, ventilation, etc.

On-Site Checks – This doesn’t usually apply to small projects. On large ones there can be a high turnover of tradespeople so the checks are helpful in identifying any problems at the time.

The Air Test – Along with the air test they check the commissioning report for the MVHR and make sure the system is working properly and quietly. If they’re happy with everything the information is sent to Germany for the authorisation to issue the certificate.

Reasons Why Buildings Fail Certification

Airtightness – Failing to test while there is still access to the airtightness layer can be a big issue in one-off houses. This needs the doors and windows to be put in at an earlier stage than a builder would normally like.

Building Services – This usually applies more in larger buildings. In particular it is poorly designed or installed ventilation units. When this happens the fan has to work harder which means greater noise.

Not Consulting Throughout – Less common is when people just build their buildings and then approach WARM for certification once it’s complete. In this instance it is likely they will not reach the standard.

As Passivhaus is about the comfort of the occupants, failing certification will mean that it may not be as comfortable as they would like, perhaps living with draughts and MVHR noise. Peter says: “Comfort is one of those strange things where, if you notice it, it’s not comfortable.”

Airtightness was the Biggest Challenge for WARM’s Own Office Retrofit

Built in the 1960s, they have transformed a draughty first floor flat into an EnerPHit standard office.

They achieved this by insulating externally, filling the cavity, insulating between the office and the shop, and putting in roof insulation at rafter level.

Deciding where the airtightness layer was going to go was the biggest challenge, particularly as the shop below was not part of the retrofit.

All the windows were also replaced with high performance triple-glazed windows and an MVHR system was installed.

Inevitably Building Regulations will Catch Up with the Passivhaus Standard

Peter considers Passivhaus as being such common sense that he believes it is inevitable that regulations will eventually meet the standard. With building regulations changing every few years to require more insulation for example, by choosing Passivhaus now your project won’t date.

Peter says: “It will happen. You’re just making it happen a little earlier.”

Find Out More

Transcript

Download a transcript of the interview with Peter Warm.

Please Connect with Us

Subscribe, rate and review us on Apple Podcasts

Follow Ben Adam-Smith on LinkedIn

Follow Ben Adam-Smith on Bluesky

September 2, 2015
HPH084 : Is the Passivhaus Standard a Good Choice in All Climates? – with Clare Parry from Australian Passive House Association
Clare Parry, Director of the Australian Passive House Association, explains what it means to work on Passivhaus projects in different climates. What, if anything, changes?

Interview with Clare Parry

Melbourne-based Clare Parry has always been interested in environmental sustainability but started out her career not knowing how to get into it. After falling into building services engineering, over time she worked with a number of inspiring people on interesting projects that naturally pushed her in the right direction.

There is Scepticism around Passivhaus in Australia

Most of the uptake so far has been in the colder areas, like Canberra and Tasmania. Much of Clare’s work is in convincing people that Passivhaus works in warm climates, and particularly well in hot and humid ones.

The physics of Passivhaus does not change, regardless of the climate.

The Indoor / Outdoor Lifestyle Leads Many Australians to Believe They Live Comfortably

The opposite can actually be true, particularly in the northern states where it can get extremely hot, and also in Melbourne and the south where it can get too cold, and where in fact 80% of their heating and cooling energy goes on heating.

Clare quotes many expats from Europe and North America who say that Australian homes are the coldest they’ve ever lived in.

In Temperate Climates Less Insulation is Often Required to Reach Passivhaus Standard

In a climate where there are extremes in temperature the insulation plays a dual role, keeping the heat out in the summer and keeping the heat in during the winter.

While there are extremes of temperature in Australia, the temperature differential is not as great as for other parts of the world, thus making it easier to achieve Passivhaus standard with less insulation.

Passivhaus is Based Around Comfort, Not Temperature Alone

There are more factors to comfort than temperature, such as humidity, air speed and radiant temperature (temperature of the surfaces). Clare cites an example in Jakarta where, despite the temperatures not being excessive, the humidity is very high so the amount of air coming into a building needs to be carefully controlled to avoid condensation.

Passivhaus school in Jakarta

The Cost Impact in Australia is High Because of a Lack of Specialist Manufacturing

Though Clare argues the cost savings are still there. An example she gives is of the specialist glazing they require, which they are only just beginning to find in Australia. This specialism, or having to import it, comes at a cost premium so the benefits are taking longer to repay.

Growing The Industry is Critical to Making it More Affordable

This is in terms of the manufacturing but also having the building industry on board too. Indeed the more people that do a Passivhaus project, the easier and more cost effective it will become for the next ones.

Demand for Passivhaus from individuals is bringing along the architects, design teams, construction industry and ultimately then the demand for the supply chain.

Castlemaine Passivhaus

“Your Home Will be Something You Engage With to Make Work”

While an Australian house is generally designed for the summer, it also needs to be designed so that it sees the benefit in winter. Clare doesn’t believe that a Passivhaus can be comfortable and efficient the whole year round without engaging with it in some way, which is probably going to be something which is manually or automatically adjustable to get the level of control.

There Are Occasions Where Passivhaus Will Not be Cost Effective

Clare concedes that there are “sweet spots” in Australia where the indoor/outdoor lifestyle works extremely successfully and where Passivhaus wouldn’t really be required.

In fact the Passive House Institute has identified several spots around the world where they can’t get Passivhaus to work cost effectively.

The beauty of Passivhaus is that the benchmark that has been established for where you do meet Passivhaus is set where the cost effectiveness is best.

Find Out More

Follow Clare Parry on Twitter

Transcript

Download a transcript of the interview with Clare Parry.

Research into the Airtightness of Homes in Melbourne

Although not strictly on this session’s topic, Clare shared some amazing research on a random sample of homes in Australia.

Until recently, the building code in Australia did not even mention airtightness! It therefore is not a great surprise to see how leaky these homes were. The purple line shows the airtightness of a Passivhaus (which you may not have noticed because it’s virtually hugging 0 ACH).

Please Connect With Me
- Subscribe, rate and review the podcast in iTunes
- Rate and review the podcast on Stitcher
- Like our Facebook page
- Follow us on Twitter
February 19, 2015
HPH069 : What is Active House? – with Rory Bergin from HTA Design LLP
Rory Bergin from HTA Design LLP explains why building standards are devised, the pros and cons, and why people adopt voluntary standards. He also gives an overview of the Active House standard.

Interview with Rory Bergin

Rory Bergin runs the Sustainable Futures Team at HTA Design LLP, a multi-disciplinary consultancy that encompasses architecture, landscape design, communications, sustainability and planning.

Most Standards Focus on Energy Efficiency

With the construction industry pursuing a low carbon or zero carbon agenda, most of the standards that have been developed in recent years focus on energy efficiency.

These include Minergie in Switzerland and the Passivhaus standard in Germany but some countries also have legislation in place to reduce carbon emissions. For example, France hopes to have carbon positive homes by 2020.

Voluntary Standards Generally Exceed Building Regulations

Rory believes that meeting a well researched, comprehensive standard takes you a long way ahead of the market.

It also differentiates you as you feel it is important enough to do this.

Standards Sometimes Don’t Transpose Well

Rory thinks there always has to be a level of local adoption or local editing of a standard to make sure it works properly. He gives an example of a project where he was comparing the carbon footprint of dwellings across Europe.

Rory says: “You have to take into account the carbon intensity of the grid in each country, which is very different. So you don’t get the results you expect simply because of the national energy policies in different countries.”

Standards Can Be Difficult to Interpret for the Consumer

While a standard may be a good framework for a developer or designer, it can be confusing to the end user.

Rory feels this is a failing of many standards because the information gets too technical and therefore is difficult for the homeowner to understand.

More Useful Information Could Aid Home Buyers

One current project at HTA Design LLP is looking at the labelling of homes. In addition to the regular sales information, such as the number of rooms et cetera, they have suggested that developers provide details on things like the amount of storage available, the daylight factor in each major living space, the running costs and how much maintenance will be required to keep this building intact.

A Good House Should Go Beyond Energy Efficiency

Active House is a specification developed by a group of pan-European industrial companies, manufacturers who provide many of the components that go into modern homes across Europe.

They were concerned that most of the standards currently being used focus entirely on energy savings. Although clearly important they believed this was not the only measure and that air quality, good ventilation and daylight should all be taken into account.

CarbonLight Homes – photo copyright VELUX

The Active House Prototypes Showed the Potential

HTA Design LLP were approached by one of the members of the alliance, VELUX, and asked to design a pair of homes to demonstrate the principles.

Rory describes how having built these houses and carrying out a study over 18 months, the occupant feedback was far beyond their expectations. They reported sleeping better and feeling healthier too.

Active House demonstration buildings have also been built in the USA, Canada, Denmark and Germany (to name but a few).

Without These Standards Homes Might Just be Built to the Lowest Common Denominator Standard

By this Rory is talking about Building Regulations, which are in place to protect us from problems from failure, but are not aimed at giving us a good experience. Even if a house is built to Building Regulations and gets planning approval, it does not mean that it will be a pleasant environment in which to live.

The Active House and other similar standards are different because they focus on providing a healthy and enjoyable quality within the building.

The Active House Standard Allows for Independence in Achieving Outcomes

Unlike the Code for Sustainable Homes which dictates for example “if you need to achieve A, then you must do B”, the Active House specification simply says that certain things, such as daylight levels and air quality, need to be achieved but leaves it up to the individual to decide how they wish to do it.

It is Early Days for the Standard But They are Hopeful of Greater Take Up

Now that the testing and demonstration phase is finishing, the Alliance are looking at ways of encouraging people to use the standard and are working towards developing a set of guidelines to help people understand how they would need to design the building and what they would need to do to achieve the specification.

There is a Danger That the Standard Could be Perceived to be a Ploy by the Manufacturer Members of the Alliance for Their Own Gain

Rory however believes that while it is fair to be mindful of where standards come from, the outcomes in this case are aimed entirely at the health and environmental benefits.

With the test of any standard being how well the building functions and the quality of the end user experience, the success of it can be measured in creating buildings that people like and want to live in.

The Aim Moving Forward Should be for Carbon Positive Homes

We’re still some way from that though, and Rory doesn’t believe we need to achieve that to achieve good quality buildings. The costs of achieving carbon positive homes are falling however and it wouldn’t be too difficult to manage on individual dwellings, however on high rise and high volume housing in cities it is virtually impossible.

Get Involved to Help Shape the Direction of Active House

Rory encourages interested people to go the website, activehouse.info, for further information and to sign up as members. With the standard being at an early stage of adoption he emphasises that the more people that get involved, the more they can help shape the direction of the standard from here on.

Find Out More

Visit the Active House website

Visit HTA Design LLP’s website

Follow HTA Design LLP on Twitter

Visit Rory Bergin’s personal blog – Sustainable Human Habits

Follow Rory Bergin on Twitter

Transcript

Download a transcript of the interview with Rory Bergin.

Please Connect With Me
- Subscribe, rate and review the podcast in iTunes
- Rate and review the podcast on Stitcher
- Like our Facebook page
- Follow us on Twitter
September 3, 2014