Tag: green building

HPH293 : What is Passive House Accelerator? – with Zack Semke

Zack Semke explains why he’s passionate about facilitating the communication and flow of information around Passive House.

Interview with Zack Semke

Zack is based in Seattle, where he works in marketing consulting services for the high-performance building industry. He is also a director of Passive House Accelerator: a website that brings together different sources of information to educate, inform, and promote the work that is being done by the Passive House community.

The construction industry has lacked innovation

Compared to other industries, construction has been famously lacking in innovation, but Zack says that Passive House is changing that. By using physics to understand how to design and construct buildings better, Passive House is re-thinking the basics of the skeleton and skin to improve performance.

The learning from new technologies will drive down costs

Zack uses the example of solar energy to show how there has been a massive drop in the cost in recent years.

He attributes this to Wright’s Law and the learning curve effect, which applies to all technologies. It says that for every doubling of units produced, there will be incremental reductions in the costs. This is brought about by the additional learning and micro-innovations that happen across the supply chain. In the case of solar energy, Zack says it looks as though every doubling of solar panels across the world brings about a fall in prices of 30%.

The same principles can be applied to Passive House buildings, so that costs can be driven down to more of a cost parity with conventional construction.

There has also been progress in the components supply chain over recent years, with triple glazed windows for example coming down in price.

And once costs become on a par, it becomes a no-brainer to build Passive House, with all the lower energy and health benefits too.

“That’s why I’m so passionate about facilitating communication and flow of information between practitioners, policymakers, marketers and whoever it is, because we want to accelerate this process as much as we can so that when a project happens in the UK and there are lessons learned from that project, we can see that learning being applied in Seattle for example.”

We know what we’re getting with Passive House!

Zack credits the focus on physics as providing such an important contribution to the sustainability movement. The development of tools like PHPP, which are not too complex or too simplistic to use, mean that there won’t be the performance gap that can be found with other green building standards.

There will be a wave of uptake

Zack is encouraged by the explosion of Passive House that is happening across parts of North America, particularly in Vancouver where enlightened public policy is incentivising Passive House and net zero construction, and New York City where carbon emission restrictions on existing buildings are being imposed, paving the way for huge numbers of deep energy retrofits.

And whereas the Living Building Challenge has been incentivised, it was designed to be exactly what it says – a challenge. Zack says that it doesn’t factor in scalability and is seen as the moon-shot of green building. Passive House on the other hand is set up to be cost optimised.

“As cities become actually serious about delivering on climate goals, they’ll recognise that there is no other green building standard or approach that rivals Passive House on reducing operational carbon emissions.”

He gives the example of affordable multi-family buildings in Pennsylvania. The body that oversees the funding, the Pennsylvania Housing Finance Agency, has prioritised Passive House in their scoring for projects that are looking for funding. It doesn’t cost the state anything to add that as a priority, and the result is that developers know if they include Passive House in their schemes they will be at greater chance of securing funding against competitors. This has seen a wave of Passive House construction of affordable housing in the state.

Pax Futura Passive House apartment building in Seattle. An example of the kind of urban infill, multi-family Passive House building that we will need to see more of in order to address the climate crisis.
Image Copyright Cascade Built

Embodied carbon is a challenge we have to address

“Operational carbon is the first thing that we need to tackle in my view, but just like so many things in the climate action space, it’s not an either/or conversation.”

Zack credits the Living Building Challenge for the new zero carbon certification, which is one of the first to consider how to reduce and offset embodied carbon.

He says the Passive House community is embracing embodied carbon as a challenge, and the Passivhaus Institute is dedicating resources to its research and thinking about tools for how it could be addressed. He would be keen to see them including energy-related embodied carbon calculations and looking at the implications of those decisions.

The Passive House Accelerator shares information and innovation

Created just over a year ago, the Passive House Accelerator is an open source global platform, that is partly a place that shares content that others have created about Passive House. They also host virtual weekly presentations by Passive House experts, followed by Q&A sessions on screen.

In addition, they present a podcast, and host roundtable discussions, on a variety of related topics.

Find out more

Visit the website of Passive House Accelerator

Follow Zack on Twitter

Transcript

Download a transcript of the interview with Zack Semke.

Climate Champions Podcast

Hattie Hartman, Sustainability Editor at the Architects’ Journal, has launched a new podcast with architect George Morgan from One Point Five Architecture.

It aims to share knowledge in an era of climate emergency, speaking to change-makers and innovators who are transforming architecture as we know it by designing in ways that respect planetary boundaries

Find out more.

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November 18, 2020
HPH195 : What is cellulose insulation? – with Gordon Lewis
Gordon Lewis explains what cellulose insulation is, how it’s applied and why self-builders can benefit from choosing it.

Interview with Gordon Lewis

Gordon Lewis has been involved with cellulose insulation for over 26 years. He mainly works installing Warmcel insulation into timber-framed properties.

Choosing insulation material is important

Cellulose became known as an insulation product in the early 1980s. Made from recycled newspaper, it is a highly sustainable product. The newspaper is milled down to make the fibres much smaller, then fire-retardants are added.

Gordon admits that man-made insulation materials are likely to continue in the market but he is optimistic about the alternatives, saying, “Cellulose is slowly creeping back into the marketplace and doing a great job.”

Paper use has declined but cellulose insulation is still available

The growth in information technology has meant a decline in the availability of newspaper for recycling. Along with overhead costs, this has resulted in some factories closing. For example, Gordon’s former employer, Excel, the sole UK manufacturer of cellulose insulation, closed down in 2014.

Sources of newspaper and cellulose insulation do still exist, however. There is one company in Ireland and there are many more manufacturers of cellulose on the continent. Gordon uses a brand called Warmcel, which is made by CIUR in the Czech Republic and shipped to the UK.

Any timber-framed building can incorporate cellulose insulation

Cellulose can be used for other build methods, but is ideally suited to timber frame buildings. Because it’s made from paper, it must be fitted in a way that avoids contact with any damp surfaces. There are a number of different materials that can make the “sandwich” containing the insulation; it might be rigid board on both sides, or one side could be a membrane.

Different boards also have different thermal performances, so it is worth thoroughly researching all the materials involved. This includes speaking to people that have had properties built, architects, builders, or the installers. Gordon says, “Ask as many questions as you possibly can to get on the right foot, to say, ‘that’s the product that I need.’”

Cost and quantity of insulation are based on location, depth and density

In order to calculate cost and how much product is needed, Gordon considers where the cellulose insulation’s going, the depth of the space to be filled and the density required. Locations could include internal or external walls, floors, an attic space or a sloping ceiling. Gordon uses formulae to establish how much material is required for that particular build.

Any moisture issues must be addressed prior to installation

Generally, before any installation is carried out with cellulose, the building needs to be wind and watertight. Cellulose will dry up and cope with a certain amount of moisture, but not too much. For example a constant leak or rainwater continually getting in to the frame would cause problems. If the doors and windows are not in, those access areas can be masked off with polythene on both sides to stop rain being driven in. Gordon will look out for water or staining on boards from rainwater that may have dried up over a day or two. To inspect for damp before installing cellulose he might drill the wall and test by hand.

Holes in the wall allow the insulation to be pumped in

The cellulose needs to fill voids created by the timber frames and rigid boards, and there can be hundreds of them to find. Experience gives Gordon familiarity with typical frame kits so he knows the small gaps to watch out for, and how to access them. He can also identify them from the screw patterns, looking at the drawings, speaking to whoever fitted the boards, or even asking them to mark the boards showing whether or not there’s a gap. If there’s still any doubt, he may drill a small hole to check.

Special sealing tape is used to maintain airtightness afterwards

Once a hole has been cut to access each void, and the insulation pumped in, the core is sealed back over the board. To make it 100% airtight, the tape must have no creases. On the job where Gordon and Ben met, the PH15 build had close to 500 holes cut and repaired. The airtightness test showed below 0.01 air changes an hour at 50 Pascal; one of the best results recorded.

After installation, moisture problems are rare and can be rectified

In Gordon’s experience, once the insulation’s in, it’s there for the lifetime of the building. He comments, “As long as the fabric and the structure of the building is sound, it’ll be there forever and a day.” He has had few subsequent issues, maybe three or four over 26 years. He believes those failures arose because people didn’t understand the building needed to be wind and watertight.

If mismanagement does result in a bad leak going into the insulation, it can be replaced once the building is watertight. Gordon explains, “We have to cut a large hole in the board, if it’s not too badly damaged, or the whole board is taken off, and then all that wet insulation is totally removed before it can be replaced.”

Experience counts but self-builders can get involved

While Gordon has a lot of expertise in his field he encourages keen self-builders to get involved, saying, “They can get to the point where they can actually install the insulation themselves, if they want.”

When he’s been on jobs where self-builders have helped, Gordon has supervised everything and made sure the equipment is set up right. Gordon uses a Krendl machine that breaks up the fibre, and then blows it from an airlock through the hose to the delivery point. Knowing that each cavity is full enough is mostly down to experience, but there are tests to check the density and location.

Cellulose insulation is gaining popularity

Gordon sees a growth in using cellulose insulation in line with a wider increase in green building techniques. More people are demanding greener products and want the benefits of Warmcel or another cellulose product.

He sees the market increasing slowly, saying, “People are looking to recycle as much as they possibly can. Whether it be the insulation, the boards, all sorts of things, and sourcing the material as locally as possible.”

Find out more

Visit the website of CIUR

Transcript

Download a transcript of the interview with Gordon Lewis

Why the location of a self build is an eco consideration

Ben Adam-Smith reflects on one aspect of his last house that he absolutely loved: its location. It was close to local amenities, and meant that Ben did a lot more walking and only needed one car for the whole family!

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November 13, 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

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March 22, 2017
HPH159 : What it took to find my plot of land – with Ben Adam-Smith
Ben Adam-Smith comes clean with his project progress! After two and a half years of looking, he has finally managed to buy a plot of land upon which to build his eco home. However, the process of buying the land was perhaps not the joyous occasion he would have liked. In this solo episode he shares what he’s learnt.

Ben Adam-Smith’s plot-finding journey

The idea of building an energy-efficient home came about in 2012. The first two years I devoted to learning in the hope that I would avoid any major pitfalls. Then the real work began. This was, of course, when I realised that finding a suitable plot in the South East of England was exactly what everyone was trying to do!

A number of times I have updated you on my plot hunt, but each time I seemed to lose out. So much so, that I had very little to show when I reached my 40th birthday midway through 2016 (which was my original self-imposed deadline for completing the whole build!).

2016 was also a ‘make or break’ year because my wife and I planned to expand our family, and so we’d need a bigger home one way or another. If we couldn’t find a suitable plot we would have been buying a new house, and at that stage not wanting to move again for awhile.

Be careful with sliding budgets

When I started this journey I genuinely thought that the equity in my current house would be enough to cover a large amount of the land and new home I wanted to build.

However, there are few plots that come onto the market at the lower end and when they do, they are either snapped up or there is something so wrong with them that everyone avoids them like the plague!

This led to us spending far more on land than we ever planned. Hopefully this is not something we’ll later regret.

Buying land seems a lot more complex than buying a house!

I have bought a number of houses over the years and don’t remember any great difficulties that have arisen during the process.

On the other hand, the vast majority of the plots we looked at had all sorts of things going on behind the scenes. What’s more, there was little transparency in bringing these to the buyer’s attention. And of course you can’t leave this work to the solicitor because at that stage you are already going through the motions.

Therefore you need to carry out your own investigation and assess any levels of risk.

Only one part of the plot is within the village boundary

Neighbours are a value source of information

I have said it before and I’ll say it again – neighbours have an unrivalled grasp on the local area.

A number of times – whether over flooding risks, private roads with no owners, etc. – I’ve had a gut feeling that there’s something the seller is not disclosing. While no single neighbour has the complete picture they can fill in parts of it. Even if there is a conflict of information, it gives you a focus.

I think, without exception, everybody I have spoken to has been helpful.

Assess the pros and cons of the site

Compared to a number of other sites we’d looked at, this plot scored highly on many counts.

It was central in a village and within walking distance of pubs, a shop and the local primary school.

At half an acre, it was actually bigger than many of the plots we’d looked at and would allow for a garden. Part of the reason for this is that the majority of the plot is on green belt land, which would not be of interest to developers, and therefore we did not perhaps face as much competition as with previous sites.

The site also benefits from having full planning permission for a sizeable dwelling.

On the downside it was expensive and was definitely right on the edge of what we could afford.

There is also a line of conifers to the south of the plot (which we do not own) and while good for privacy it blocks out a lot of the low winter sunshine.

And as the building plot is close to existing buildings there are constraints with the ridge height for part of the roof, and overlooking issues.

Expect a few sleepless nights

I had a lot of issues with fear. I was spending more money than I’ve ever spent in my life. You obviously do your best but it’s so difficult to tell if there are still issues lurking somewhere!

There was also the big shift in my financial situation. I would be reducing my assets and income, and creating a liability. The reality of moving from a comfortable position to less comfortable one was and is scary!

A line of conifers cut out winter sunshine

Self-builders invariably become attached to the land they’re bidding on

This is a huge disadvantage because you may make different decisions compared to buying an investment asset, for example.

If you can keep some distance in the process then you will be doing yourself a favour.

The land equation exists for a reason. Operating outside it will leave you losing money when you come to sell.

I’m not sure I did a great job on this point, particularly when I discovered that this plot was part of a farm one of my ancestors once owned.

Make sure your solicitor does not delegate to a junior member

We’d developed a relationship with our solicitor before we hired her, but what we didn’t realise is we wouldn’t be dealing with a different person! It was handed onto a junior member and this became apparent through the process.

As the transaction was time bound – which is something you should try to avoid if at all possible – the senior solicitor had to take over towards the end of the process.

Have cash available for exchange and completion

Don’t use cheques! This was a lesson we learnt the hard way.

We technically had the money, but didn’t have the money sitting and waiting in our account (as we’d previously been advised by people like Mark Brinkley!). So the process of transferring from one place to another would take 10 days to clear by cheque. Needless to say, this was too long. That meant having to cancel cheques and redirect funds via CHAPS, which is what we should have done in the first place.

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January 11, 2017
HPH042 : Can a Straw Bale House Reach Passivhaus Standard? – with Fran Bradshaw from Anne Thorne Architects
Fran Bradshaw from Anne Thorne Architects shares her experience of building an ultra low energy home using natural materials such as straw bales, lime render and clay plaster. The house is also aiming for the Passivhaus standard.

Interview with Fran Bradshaw

Fran Bradshaw was a builder before she became an architect but she’s still very much interested in the practical side of things. A lot of the work she does at Anne Thorne Architects has a focus on sustainability and community-based work.

This episode is about a straw bale house that she’s building for herself in Norfolk, UK.

Straw Bale Building Allows People to Get Involved

Fran got inspired to build her own house with straw after working on a project for Haringey Council.

Local people helped both design and construct the eco-hub, which Fran describes a wonderful experience: “It was really exciting being on site and just seeing how enthusiastic people were and what a great community benefit it was.”

Volunteers help construct an eco-hub in Lordship Park

Natural Buildings Feel Different

Upon completing the eco-hub, Fran noticed that lots of people commented on the quality of the environment.

The acoustics, humidity and the colours are all very different in a building constructed of natural materials – people liked this.

The finished eco-hub (credit: Rae Parkinson, Straw Works)

Getting the Details Right is the Biggest Challenge

While there have been straw bale houses in mainland Europe that have reached Passivhaus standard, there is yet to be one in the UK.

The challenge is in turning what is a rather chaotic building material into something that is actually very precise, because to achieve the Passivhaus standard all the details on all the joints have to be very neat and carefully airtight.

The timber frame goes up on Fran’s house

The Team Must be Led by Someone Experienced

Although one of the reasons Fran chose to build her house with straw was to involve her friends, she leveraged the experience of Straw Works.

So guided by one or two experts, the rest of the team members just need to be enthusiastic and prepared to do a little bit of physical work.

Barbara Jones from Straw Works examines the quality of a bale

A Reed Thatch was Chosen for the Roof

The site is very close to the Norfolk Broads and Fran discovered that reed thatch was being cut a mile away.

She describes this as too tempting: “Yes, it’s just a very good roofing material. It’s very durable. It’s got a natural insulation value so there was no reason not to use it. I mean it’s more expensive going with thatch rather than clay tiles or something and that was my extravagance really.”

Reed Consistency is Important

In order to thatch well, the reeds need to be the same strength, the same length and have the same diameter.

This is partly to do with how well and methodically the reeds are cut, which is why reed cutters are given long contracts to tend a certain patch.

The Airtight Layer in the Roof is Below the Thatch

The thatch is on fireboard which is moisture permeable but airtight. It’s taped at the joints so that the airtight layer is just underneath the thatch.

Warmcel – recycled newspaper insulation – then goes in between the plasterboard and the underside of the fireboard.

The Floor is a Reinforced Raft

Fran says the connections between the walls and the floor are always tricky to get right and, as this project is aiming for the Passivhaus standard, she opted for a reinforced raft.

While there was a level of compromise here it is quite economical on concrete and it gave Fran the opportunity to employ a local contractor (whereas many parts of this build have needed specialists).

Due to Timber Penetrations the Airtightness Layer is on the Outside of the Wall

Normally the airtightness layer would be on the inside of the house to avoid warm, moist air from the room going into the wall fabric.

As there’s timber inside and the straw is outside the timber frame, in this case it would have been very difficult to make the airtight barrier work well (because there are timber penetrations and quite big bits of timber).

After discussing the best approach with their airtightness expert Paul Jennings, they decided to use the outside layer of render as the airtight layer.

So the concrete slab is the airtight layer in the ground which connects to the lime render on the outside of the straw walls and then to the fireboard on the roof.

A Theoretical Risk has been Managed

There is a theoretical risk to having the external lime render as the airtightness layer as Fran explains: “Inside you’ve got clay plaster and that effectively is airtight as well but for instance at the windows where it’s all taped it’s on the outside, so theoretically you could get moist air going at the junction between the internal plaster and the window and condensing within the straw.”

They are pretty confident this won’t be a problem because all the materials are moisture permeable and hygroscopic as well, and the MVHR ventilation will be operating at the coldest times.

Moisture monitors will also provide on-going data, so should any issues arise they can be addressed.

The Clay Plaster and Lime Render Will Need to be Maintained Every So Often

As the lime render is the airtight layer, any cracks that appear could affect the airtightness and thus the energy efficiency of the house.

However, this is just part of using these materials – these cracks will need to be repaired. Fran is expecting this at the end of the drying out process but is not sure how often the maintenance will be after that.

Nearing completion!

There’s a Role for an Airtightness Geek!

Working with these kind of materials and trying to achieve high levels of airtightness, Fran can definitely see the need for a ‘very precise airtightness geek person’ who has a close eye on all the details as the build progresses.

This could develop within building firms or be a role that is taken on by a broader group of people.

Prepare for the Key Moments

There are certain key moments where you’ve got to be absolutely spot on, so find out where these are.

Planning for those moments and making sure that there are the right people around at the time will stand you in good stead.

You Can Always Do Things for Less BUT . . .

While Fran knows that there are always ways to cut costs, she derived great pleasure on this project from being able to work with people who she knew were going to do a really lovely job.

Although she may have paid a little bit more it’s been worth it and she still believes it’s been reasonably economical given the materials used.

Invest in People

Look carefully at what people have done in the past and trust your judgement about them.

For work like this Fran is not in favour of endless competitive tendering. On the whole she’s selected people who she enjoys working with and who charge a reasonable rate for what they do.

Passivhaus is a Language We All Understand

The first air test of Fran’s house recorded a figure of 0.9 air changes per hour.

She still hopes to meet the Passivhaus standard: “I’d really like to certify it because it’s a language that we all understand. Either you’ve achieved it or you haven’t. If we don’t achieve it, that’s okay, we’ll have got very near it and the difference in the building performance between not quite achieving it and achieving it is really quite small. It’s just very exciting for me to have this house and this opportunity to live in it.”

Find Out More
- Anne Thorne Architects
- Read their blog all about Fran’s straw bale house
Transcript

Download a transcript of the interview with Fran Bradshaw.

Our Question for the Comments Section

Have you managed to incorporate natural materials in your project? And if not, why?

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February 18, 2014
HPH040 : Is the Passivhaus Standard a World Standard? – with Martin Holladay from Green Building Advisor (Passive House)
Martin Holladay from Green Building Advisor talks about the pros and cons of the Passivhaus standard. He also explains why he believes the German standard is not the best approach for the North American climate.

Interview with Martin Holladay

Martin Holladay is a senior editor at Green Building Advisor and Fine Homebuilding magazine, and he reports on topics relating to energy-efficient residential construction.

He started out as a builder and remodeler, building single family homes, additions and renovations in Northern Vermont in the United States.

About 15 years ago he got into publishing, first as an editor at the Journal of Light Construction and then later at Energy Design Update.

Martin built his first house in 1974

Martin’s First House was a Learning House

Martin describes the first house he built for himself and how it followed passive solar principles. It was not an airtight construction though.

He calls this a ‘classic hippy house’ in the sense that it was thrown together with found materials and inexpensive items that he picked up from the dump.

The Solar Years

Martin explains some of the history of how green building advanced through the years.

As early as the 1940s, MIT researchers were looking at different ways of collecting solar energy.

Active solar systems used pumps and blowers as well as some mechanism for storing solar heat.

Martins says: “If it was a solar air system the heat was usually stored in a rock bin, usually in the basement which was literally a large bin of rocks through which heated air would be blown. Then the air would later be blown through the rocks on a cold night and some of the heat would be gathered up that way or more commonly in large tanks of water. And solar collectors on the roof, water collectors or air collectors would – with means of pumps or blowers – transfer this heat to the storage system.”

Passive Solar Homes

Passive solar houses aimed to use the design of the house to maximise solar gain and not use pumps or blowers.

With most of the windows on the south side of the house and fewer on the north, Martin says these houses heated up quite nicely on a clear sunny day.

There were drawbacks though. They lost a tremendous amount of heat on cold winter nights because of the large amounts of south facing glazing. So they had the reputation of being uncomfortably hot on sunny days and uncomfortably cold at night!

The Saskatchewan Conservation House was built in 1977

The Saskatchewan Conservation House was a Breakthrough

Instead of just gathering solar energy, this house also experimented with super insulation. So it was a house that was built on airtight principles and was tested at about 0.6 air changes per hour at 50 pascals.

It had R40 walls, R60 ceilings and used triple-glazed windows. Clearly these types of specifications have been recommended ever since in cold northern climates (for super insulated houses).

In 1985 The Superinsulated Home Book (affiliate link) was released and a whole movement advocating super insulated houses took off.

The Traditional Approach to Passive Solar Home Design was Abandoned or Modified

Martin explains that at this stage there were two opposing views of the best way to build a low energy house.

“The traditional passive solar people thought that you could get there by collecting lots of energy and the super insulation people thought that collection of energy was not really the issue. The issue was building a tight enough envelope that you didn’t lose energy and on balance I think the super insulated group has been proven correct and a lot of the early ideas of so-called solar house design have long since been abandoned or modified.”

The Passivhaus Standard Requires Cold Climate Builders to Invest in an Extraordinary Amount of Insulation

Martin believes that the goals for annual energy use required by the Passivhaus standard – the most famous of which is 15 kWh per m²per year – are fairly arbitrary.

He continues: “By pegging an energy budget on the standard he [Dr Feist] required cold climate builders to invest an extraordinary amount of money in insulation that will never foreseeably be recovered in any possible energy savings.

“When true believers in the US started copying the Germans using the Central European standard in our climates they were ending up with 14 inches of rigid foam under their concrete slabs, they were ending up with R100 insulation in their attics and they were sometimes paying $6,000 or $10,000 for reducing tiny amounts of annual energy use that could easily have been supplied by a $400 solar panel producing electricity. It was this kind of absurdity that created a backlash in North America.”

For this reason Martin says the Passivhaus standard has no global validity.

Cellulose insulation

The More Insulation You Use, The Less Effective it Becomes

Insulating infinitely does not make sense, so there will be a point where it is no longer cost effective.

For example, doubling the thickness of the insulation will cut the heat loss in half, but each time it’s doubled it’ll mean spending more and saving less energy.

We can only estimate how much to spend on insulation.

Martin explains: “You guess at the lifespan of the building, you guess future energy costs, you put a dollar figure on the amount of energy you will pay over the lifetime of the building and you try not to spend more on insulation than will ever be saved in energy.”

Global Warming Mitigation Efforts Need to be Cost Effective

While it could be argued that very thick insulation saves the planet, if this is only includes houses for the wealthy – that are extraordinarily expensive – this is probably not a wise investment.

Money should be focussed where it has the greatest potential to reduce CO₂levels.

Passivhaus is Not a Religion

While Martin praises the Passivhaus standard for focussing on the right things, he says it’s not a religion and it shouldn’t be blindly followed.

He also hopes that it doesn’t become enshrined into building codes because it takes away flexibility from builders.

There Needs to be a Massive Investment in Renewable Energy

In order to preserve the planet for our kids, it is a must that we become free of fossil fuels.

This means a huge investment in photovoltaic arrays, wind turbines, tidal energy (to some extent) and so on.

Local Communities Need to Embrace Renewable Energy

Martin is troubled by the fact that in the US it is becoming increasingly difficult to site renewable energy installations.

This is because local interests oppose wind turbines and in some cases PV installations as well because they are afraid that it will be a blot on the landscape. Unfortunately this comes at a time when we need to be moving at a faster pace, not a slower pace.

Efficient New Homes Alone Will Not Impact Our Climate Crisis

The timetable for building new homes is an entirely different timetable from the one required by our climate crisis.

Martin stresses we have to get a handle on this crisis within the next 10 or 15 years, or we are very much in trouble.

So building new super insulated homes does not address this issue. It is weatherization (or retrofitting) of existing homes that will be most significant.

There are clearly many other things that could be done outside construction.

Listener Questions

1. Juraj Mikurcik asked, “What’s the biggest barrier in the uptake of large-scale, multi family Passivhaus in the US?”

2. David Cummings asked,”What are your thoughts on the marriage between natural building and Passivhaus and embodied energy?”

3. Thomas Langley asked, “Is it better to pay the extra money to go all the way to Passivhaus standard or do as builders all recommend and compromise on airtightness to save money?”

Transcript

Download a transcript of the interview with Martin Holladay.

Our Question for the Comments Section

Is getting Passivhaus certification important for your project?

New York, New York – Las Vegas

Back From New Media Expo

I’ve been in the United States on a business trip to attend New Media Expo. It was very worthwhile and I met some amazing people who are also trying to change the world for the better with their blogs, podcasts and online videos. Unfortunately at the end of the conference, perhaps due to information overload and a lack of sleep, I had a psychotic episode and ended up in hospital.

Although I want to tell you this story (if you’re interested) I did not feel that the House Planning Help Podcast was the right place to do it. Luckily, Ellory Wells, invited me onto his podcast and I shared the tale with him.

My Empty Flight Back from Las Vegas

I said in the introduction to this podcast that I was shocked by how few people were on my plane travelling between Las Vegas and London Gatwick. Here is the proof! This photo was taken in the air and has not been doctored.

There must be a better way of organising flights so that planes are always at capacity?

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January 22, 2014