Tag: windows

HPH193 : Should you specify uPVC windows? – with Simon Corbey from ASBP

Simon Corbey from ASBP shares some of his research into the costs and life cycle of plastic windows and suggests some considerations for self-builders.

Interview with Simon Corbey

Simon Corbey worked as a chartered surveyor in the ‘90s, and went on to become a specialist in natural paints for London’s first eco builders’ merchant, Construction Resources. He has also worked for BioRegional, the Sustainable Development Foundation, the Good Homes Alliance and the Alliance for Sustainable Building Products (ASBP). Last time we spoke to Simon, he talked to us about healthy building products.

We should question the chemicals in uPVC

Simon Corbey has been working on behalf of the ASBP to compare plastic and timber windows. Consumers tend to be more concerned with how windows will look and last than where plastic comes from and the issues around it. Simon remarks that plastic windows are manufactured widely in the UK, but these impacts are not really considered, adding, “I do think that there’s an opportunity for the UK to develop their building physics and approaches to making windows.”

Simon notes that plastic windows appeal, as they are generally cheaper and available in a range of styles. He describes the marketing as aggressive, adding, “It’s well funded, of course. It’s the petrochemical industry.” Plastic windows contain a range of chemicals but no research has suggested a negative effect on indoor air quality. The window itself may be benign, but Simon has also been researching product manufacture and life cycle.

Manufacturing chlorine is hugely energy intensive

Simon explains that uPVC (unplasticized polyvinyl chloride) contains chlorine. Used in swimming pools and our water supply, it’s common enough to not raise concern. However, he explains that its manufacture has an incredible impact on the environment.

Simon estimates that producing 80% of the UK’s chlorine uses more electricity than Liverpool. Production of PVC in Europe in 2015 used 8.6 million tonnes of chlorine. “So it’s hugely energy intensive,” says Simon, adding, “From a life cycle analysis it’s a terrible, terrible thing.”

Simon’s research shows the hidden costs of uPVC windows

Simon has further researched Ineos, who produce most of the UK’s chlorine. Describing it as “a very murky world,” he says he feels motivated to bring this to people’s attention. The site of the Ineos plant in Cheshire is of particular concern. Simon describes how Ineos were caught dumping mercury into the Manchester Ship Canal in 2014 and the land contains a dump once used to “make everything from nuclear weapons to World War II stuff”.

Previously owned by ICI, the dump was linked to toxic chemical leaching and reports of ill health in the early 2000s. Today, explains Simon, if you look at the Land Registry, this dump apparently has no owner. “There is a completely toxic dump just there which the council don’t own,” he says. “Ineos have somehow redrawn the lines of their site and conveniently they don’t own it any longer.”

Timber windows struggle to compete on price and marketing

Despite their significant environmental price, plastic windows remain cost effective for manufacturers. The price of oil and gas is still low, making the raw materials cheap. The process of gathering timber, processing, sawing and milling it is quite energy intensive in comparison and the end product is heavier to transport. All of this adds to cost.

Simon further points out that the UK timber industry is quite fragmented, containing many different disparate interests. Conversely the plastics industry markets products with “one voice”, typified by slick campaigns, such as that for Everest windows. Moreover, Simon describes it as quite litigious, recalling a threat of court action when his former employer persuaded a Scottish Housing Association to cancel their order for plastic windows.

Plastic windows may not outlast timber

There is a perception that timber windows will rot, requiring repeated maintenance, while plastic is assumed to be tougher. Simon questions these preconceptions. While acknowledging that timber windows have a finite life cycle he points out that plastic windows are prone to yellowing after a while. Simon himself has 120-year-old timber windows, which are “going strong”. “They’re a bit leaky,” he says, “but they’re okay as far as I’m concerned.”

Other options for window materials do exist. Simon recommends considering factors such as product life cycle and building location. Aluminium is very durable but highly energy intensive; composite timber and aluminium windows are one alternative.

The quality of UK timber windows is improving

Windows are an essential part of the building fabric’s performance. With improvements in building science, double glazed and triple glazed windows are appropriate for new builds and both plastic and timber windows can achieve Passivhaus Trust certification.

Where good indoor air quality is maintained by natural ventilation, windows must function well, being easy to open and clean. There have been some issues of quality with some timber windows but Simon sees this improving, following the standard of European and Scandinavian manufacturers.

Recycling plastic windows involves additional expense, chemicals and risks

The Scottish Civic Trust suggests that the recycling rate for windows might be 3% and according to the Green Guide, BRE suggest that the UK average is about 15%. However, Simon suggests the many issues with recycling, such as the chemicals and risks involved, make that figure optimistic.

The formulation of plastic has changed quite a lot since the ‘60s and the industry has made great attempts to clean itself up. Substances considered by REACH to be of very high concern, such as lead and cadmium, are being phased out although tiny quantities are still allowed.

Plastic is worse than wooden windows in a fire

Simon believes that toxicity is a huge issue. He confirms that plastic windows pose a greater risk than wooden ones in the event of a fire and believes that more research is needed. However, currently all the testing institutes are very busy “as a result of Grenfell”.

Simon notes that in the USA, The Healthy Building Network has liaised with the Fire & Safety community to argue for a complete halt to use of plastic products. Likewise, the ASBP has initiated contact with Kent Fire and Rescue and the London Fire Brigade. As Simon explains, “there is some research underway but it’s early doors, I would suggest, this type of testing.”

Industry and consumers are moving away from plastic

Techniques and attitudes continue to change. Acetylated wood is an example where window science has improved. This process basically uses vinegar to extend the maintenance life of timber to over 60 years.

Simon notes a growing interest in health and wellbeing, as well as a global campaign against plastics. He summarises, “I think at ASBP we’re trying to suggest that as a society we’ve just got to start using less plastic through and through, in all the things that we do and windows being one of those things.”

Find out more

Visit the website of the Alliance for Sustainable Building Products (ASBP)

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Transcript

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October 3, 2017
HPH186 : Choosing windows for a Passivhaus home – function versus aesthetics
Ben and Kay Adam-Smith have a difference in opinion over which windows to specify for their new build Passivhaus home. While Ben is keen to minimise mullions, transoms and window frames, Kay believes this takes away from the aesthetics of the building.

A visualisation of Ben and Kay’s house

Today’s episode is really a short story about aesthetics. Life would be boring if we all liked the same thing. However, what happens when you’re working with your other half on a self build and you strongly disagree about something? How do you move on? Well we haven’t answered that one yet, but we can share the disagreement and let you know what happens over the course of time!

I (Ben) also feel like I might have said what my wife is saying a few years ago. I believe I’ve grown in my understanding since then and so now my opinion has changed.

Mullions, transoms and window frames

Firstly what are mullions and transoms? Well, they are the structural elements that divide up sections of a window. Mullions are vertical while transoms are horizontal.

There’s no denying that the use of mullions and transoms can make some beautiful windows (as in the stained glass window above, where it’s taken to an extreme).

In the past it was just not possible to manufacture large single pieces of glass and so to achieve a big window, a number of small ones needed to be ‘stitched’ together.

Large glazing is now possible

Probably a window’s most important function is to provide that visibility from one side to the other.

Windows without mullions and transoms therefore do a better job of connecting the inside to the outside (and obviously bring in more light).

As we spend 90% of our time indoors, you could argue that the view out is more important than the aesthetic appearance of the window from the outside.

Large single pane windows are still not the norm

In a country where our period properties make up a large proportion of the housing we live in today, it is hardly surprising that we gravitate towards their features.

That’s perhaps why Kay would like two of three ‘lights’ (subdivisions) in each window.

She also thinks that a lot of houses that use large panes of glass just don’t look right; they look like they need to be sub-divided.

Reducing the amount of glazing in a window affects its performance

The frame is generally the weak point of the window.

Chris Parsons of Parsons + Whittley says: “We want more glass and less frame in the way, because the more glass we have the better the performance of the window. When you start dividing them up with mullions and transoms, you now can’t insulate that part of the frame by wrapping anything around it.”

How much glass is actually in a window?

PHPP models the amount of glass and the amount of frame

Even if a window has a good central pane U-value (a measure of how effective it is as an insulator), it is only referring to the glass. Therefore the Passive House Planning Package (PHPP) requires information on both the amount of glass and the amount of frame in every window. This is the only way to produce an accurate model of the thermal performance.

The ease of opening and closing windows depends of their size

While performance is important when creating a Passivhaus, it must also be balanced with practicality.

When windows get too big, they take a bit more manoeuvring so this could become a valid reason for introducing different lights in certain windows.

Aesthetics will always be a key driver in window choice

There is no doubt that windows with mullions and transoms produce a pretty pattern on the window.

It is also possible to get Passivhaus sash windows, for example. However, for new build, does it make sense to specify sash windows (given all the arguments above)?

This is a choice you’ll have to make . . . and a choice we have to make on our build!

Keep an open mind

This can be a great attitude to anything in life and it’s just the same with architecture.

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August 11, 2017
HPH065 : How Simple Design Decisions Can Impact on Energy Performance – with Alan Budden from Eco Design Consultants
Alan Budden from Eco Design Consultants explains how simple design decisions can drastically alter the energy performance of a house and why this means your designer needs to be using a tool like the Passive House Planning Package (PHPP) to better inform these decisions.

Interview with Alan Budden

Even as a kid Alan Budden was interested in buildings and architecture.

After training as an architect he became an associate at PRP Architects, where he designed one of the UK’s first 5-star houses at BRE Innovation Park.

For the last five years he’s been running his own practice Eco Design Consultants as well as teaching architecture at Birmingham City University.

Some Forms Are More Efficient Than Others

The building shape – or form – can make a huge difference to the energy performance. This is because heat loss occurs through the external walls and fabric of the building, and so the more surface area there is the greater the losses.

The diagram below shows how three houses with the same floor area – in this case 100m² – perform differently (assuming the U-values are constant throughout).

The simplest shape possible would be a sphere but that would not be practical to build or utilise! So the next most efficient form is a cube (in terms of best floor area to surface area ratio).

An Efficient Form Factor Reduces Building Costs Too!

As the most expensive part of a building is the outside envelope, an efficient form gives you maximum floor area for the minimum amount of materials (and thus keeping costs low).

Energy-Efficient Buildings Must Fulfil Their Function AND Give Delight

Simple buildings don’t have to be boring! It’s about using different materials creatively and adding to the facade.

Alan tells the story of why he put a narrow floor-to-ceiling window in his Howe Park project because kids love to be able to see out! Although in energy terms it could have been dismissed, it provides delight.

Window Frames Are Probably the Weakest Point in a Building!

While the U-value of an external wall could be as low as 0.1, for a window frame it’s likely to be around 1, which would be 10 times worse.

So choosing windows that minimise the amount of framing makes sense.

The diagram below shows some different examples.

When Making Design Decisions We Need to Understand the Impact on the Whole Building

Although putting in a dormer window might not make sense in terms of energy efficiency, it could still be a feature that you want.

So in order to keep on track in producing an ultra low energy home, it is therefore necessary to make up for it somewhere else (perhaps by increasing the insulation).

This is why modelling the building in the Passive House Planning Package (PHPP) is so important in understanding the overall picture.

Howe Park, Milton Keynes

Building Regulations Sets a Poor Benchmark for Airtightness

Alan is the architect behind one of the world’s most airtight buildings, Howe Park.

With an airtightness result of 0.07 air changes per hour this means that the house is 355% more effective (in terms of heat losses) than one constructed to UK Building Regulations (which is 10)!

Alan says: “Even with a building regulation house now built to fairly good standards, not quite to Passivhaus but pretty good, if you had an airtightness of 10 you’d be losing as much heat through draughts as you would through the insulation.”

Airtightness is Really About Reducing the Draughts in a Building

Alan thinks about airtightness in the same way as the old Everest advert! It’s really about reducing the draughts.

Very Airtight Buildings and Quality Go Hand in Hand

As Alan completes more and more Passivhaus projects he believes it is raising the quality of the builds.

When everyone on site knows there’s going to be an airtightness test at the end, they make sure there is attention to detail in all areas.

Interior of Howe Park

Find Out More

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Transcript

Download a transcript of the interview with Alan Budden.

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August 7, 2014
HPH038 : What Type of Windows Do You Need in a Passivhaus? – with Bronwyn Barry from One Sky Homes
Bronwyn Barry from One Sky Homes explains the evolution of windows and why modern windows are really pieces of equipment. She also shares what’s involved when it comes to choosing high performance windows for a project.

Interview with Bronwyn Barry

Bronwyn Barry is originally from South Africa but she studied architecture in America and never left!

Her passion is for integrating good design with comfort and performance. When Bronwyn discovered Passivhaus, she felt it had the whole package.

The Smartwin window system

Windows Have Become More Sophisticated Over Time

A window traditionally has two functions. Firstly it lets in light or air, and secondly it allows the dweller to see outside (or vice versa).

In a high performance building, the windows are likely to be the weakest link in the chain when the whole building envelope is considered. So how the windows are built and how they are designed into the envelope is critical to making the full package work.

Historically Windows Have Even Told Stories!

Early windows were just tiny openings in buildings with no glass. As glass became more available, windows even became a status symbol for the wealthy.

Bronwyn talks about the glass tax in Ireland where people were taxed on the number of windows they had!

Gothic cathedrals really pushed the boundaries of what windows were, using them to tell biblical stories.

Building Science is Nothing New

Bronwyn reflects on a trip to Frankfurt in Germany where she visited the Goethe House. On the top floor are the original leaded glass single pane windows from the 1600s which have a channel at the base and weep holes to allow the interior condensation that would form to drain to the outside.

Bronwyn found this fascinating that building science was being used to come up with solutions centuries ago.

Domestic Markets for High Performance Windows are Growing

When Ben asks whether a Passivhaus needs different windows to any other building, Bronwyn says not necessarily. However, the windows must be very carefully designed and selected, taking in account the climate, orientation of the building and the materials.

The good news is that there’s more and more choice on the market. While imports (from countries such as Austria and Germany) have dominated Passivhaus projects in recent years, local producers have cottoned onto the growing market and have started producing appropriate windows and even customised products for their specific markets.

Windows Need to Function Differently According to the Project

There are variables to take into account such as the solar access of the site. The energy balance will change according to the size of the building. Taller buildings, multi-family units etc. will have large internal gains compared to relatively small gains on single family, detached residences.

Bronwyn explains with an example of one of her recent projects which had no solar access: “I’ve recently done a retrofit where our windows weren’t net energy producers. What I mean by that is the overall energy gain from the solar gain of the windows was actually less than the amount of energy that gets lost out of the windows, just because they are a weak insulation component in your full envelope. That was in California, where we’ve got really great solar access and a relatively mild climate but this was a project that had a whole line of redwoods across the southern border of the property completely shading the house. So we really had to choose our windows that would give us lots of natural light, which people still always want no matter where you are on the planet, and wouldn’t lose too much heat and maintain a relatively comfortable interior temperature.”

Aesthetics Tend to Come First When Choosing a Window

In Bronwyn’s experience choosing windows for a project generally follows this sequence:
1. Select the ones you like the look of
2. Look at the performance data to see they are adequate
3. Consider the price
Another factor to bear in mind is what materials the windows are made from. Some people do not want any uPVC on their projects!

Glazing Selection has a Big Impact on Heat Gains

The glass that is chosen to go in the frame has a huge influence on how much heat gain there will be from that window. Again, this is due to a combination of factors.

For example, quite often there are double pane or triple pane. There are a variety of films and coatings that can be applied to the glass too. Different gas fills can also go in between the panes, adding an extra layer of insulation.

Do Gas Fills Leak Out Over Time?

Ben raises the concern that these gas fills in the windows may not last and Bronwyn responds that in a recent study of a 10-year old window it was found that only a very small amount of the gas had escaped.

There is currently debate that at high altitudes this could be more of a problem but even then there are workarounds.

Bronwyn says: “If your glazing panel already has very poor performing spaces, so if they’re aluminium spaces holding the two panes apart that’s already probably a worse thermal bridge kind of heat loss opportunity than no gas in the window. And if your frame is a really poorly insulated frame that’s another bigger opportunity for worse heat loss. Then if the installation, how the window’s installed within the wall opening, if that has all sorts of metal pans that go from the inside to the exterior and big air leaks there again is another bigger offender.”

Rough opening framing with air-sealing tape

Everybody in the Chain of Custody has to do a Good Job

It is not a case of just buying a really high performance window and the job is done, because if it is put in a sub-optimum position in the wall or is not sealed properly to the building fabric, the overall performance will be diminished. So it is very much a team effort. Good communication and a little education can go a long way.

As Passivhaus requires a blower door test it quickly reveals any poor workmanship, both in the production of the window and the installation.

Solar Gains Need to be Carefully Controlled

With the opportunity for windows to be great solar gain mechanisms they essentially become the heating system for these buildings. However, if this is not controlled carefully it will become an over-heater for a building which is also not desirable.

This was Bronwyn’s childhood experience in South Africa, where overheating and being uncomfortable from excessive heat was more the issue rather than lack of heat.

So being able to shade the windows carefully and control the solar gain is just as critical as the window design and where they are located in the building envelope.

Exterior operable shades in Berkeley, CA

Your Shading Mechanism Should be a Long Term Proposition

There are various shading mechanisms that can be used on a project such as an eaves overhang and brise soleil to exterior louvered blinds or a neighbouring building. Even trees can be used as part of your strategy. The important point is that it is a lasting solution.

On high rise buildings it can actually be a coating on the glass itself that modulates the solar gain.

Balance Project, New Mexico (Image courtesy Jonah Stanford)

The Importance of the Window Frame is Often Over-Looked

While architects and energy modellers can get engrossed in the glass specification the actual frame design itself can get skimmed over. The frame can make or break a high performance window.

The glass can be replaced and most manufacturers provide a good selection of glass inserts but when it comes to the frame there are normally only a few options.

That’s why Bronwyn’s top tip is to pay attention to how well a window is put together and also how it drains at the sill.

Transcript

Download a transcript of the interview with Bronwyn Barry.

Our Question for the Comments Section

How have you chosen windows?

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December 18, 2013
HPH025 : The Myths of Passivhaus (Passive House) – with Elrond Burrell from Architype
Elrond Burrell from Architype helps bust some of the common myths that surround the Passivhaus standard.

Interview with Elrond Burrell

Elrond is originally from New Zealand, which is also where he trained as an architect, but in 1998 he moved to the UK. After working on various sustainable projects he then joined Architype in 2006 and became more aware of the Passivhaus standard.

The Passivhaus Standard was Developed to Close the Performance Gap

Passivhaus is a performance standard for a building that is not specific to the type of building. It was developed over 20 years ago by professors Bo Adamson and Wolfgang Feist, who were looking into why buildings didn’t perform as well as they were predicted to do. By carrying out lots of careful analysis they established that in order for a building to be comfortable and energy efficient, it needs to be airtight, well insulated and have good ventilation.

Understanding Passivhaus with Coffee!

Elrond gives an example of two ways that you could keep your coffee warm. In the first situation there is a hotplate, where energy is continually put in so that it keeps bubbling and at temperature. In the second scenario the hot coffee is poured into a thermos flask and kept warm by screwing the lid on. Passivhaus works in the same way. Some warmth must be provided initially, be it through solar energy from the sun, occupancy heating (movement) or cooking, etc. But, by having the building built correctly and well insulated that heat is kept in so that you are not losing it.

Mechanical Ventilation with Heat Recovery Provides Fresh Air Without Losing the Warmth

Instead of throwing out all the warm air and bringing in fresh cold air which then has to be heated, mechanical ventilation with heat recovery allows fresh air to be brought into the house and the old air to be expelled but importantly the heat is retained.

The Myths of Passivhaus

This episode is slightly different from any that we’ve done in the past. We put out a message on Twitter asking Passivhaus builders and designers to tell us what common misconceptions they hear. Now we discuss the items that cropped up the most.

A Passivhaus Heats Itself – MYTH

This is not factually correct, because nothing heats itself. A Passivhaus needs to get the heat from somewhere, but a Passivhaus building retains the heat (as discussed above).

You Can’t Open the Windows in a Passivhaus – MYTH

This may be easy to buy into but in a Passivhaus there is nothing to stop you from opening the windows. Elrond says that it really depends on the time of the year and what you want as to whether you open the windows. In summer (UK) it is likely that the mechanical ventilation would not be running anyway, so natural ventilation would be important and that means opening the windows. In winter there’s probably no need to open the windows because there’s enough fresh air and it doesn’t feel stale or stuffy. In a traditional buildings that’s why people tend to open the windows in winter because it’s stuffy, which is essentially the CO2 levels getting a bit high, whereas in a Passivhaus there’s constant ventilation in the background and there just would not be the need.

The Aesthetics of a Passivhaus are Not Good – MYTH

Elrond suggests that many of the first buildings to meet the Passivhaus standard were located in Germany and Austria, and so had a continental aesthetic. As these buildings attracted a lot of publicity it is no great surprise that there is the perception that a Passivhaus will look a particular way. Also, many of the initial attempts at doing Passivhaus may have mimicked these buildings as designers were grappling with a new challenge. However, as time goes on, Elrond believes we are seeing more buildings in the local vernacular styles.

Having worked on three certified Passivhaus schools, Elrond is proud that Architype achieved a similar aesthetic to their non-Passivhaus schools.

A Passivhaus Must be Built with Sustainable Materials – MYTH

Elrond finds this one interesting because he hears the other argument, that Passivhaus doesn’t put enough emphasis on encouraging use of natural materials. At Architype they have always had an interest in using healthy materials that don’t emit noxious fumes, so that there is no knock-on impact with occupants suffering from conditions such as asthma.

The choice of which materials to use in a Passivhaus will normally be determined by the designer or client’s preference. When it comes to insulation there are also complexities in balancing how much carbon might be involved in the materials, for example using polystyrene, and how much carbon is being saved due to the energy saving attributed to a good insulating material.

Building a Passivhaus is Too Expensive – IT DEPENDS

Elrond says there’s quite a lot of published data which shows that Passivhaus buildings can cost more than non Passivhaus buildings. However, when designing a Passivhaus building it’s a quality assurance standard, so what gets built has to match what gets designed and it has to meet the appropriate standard of workmanship on site with the finishes, etc. Thus, comparing that with a building that only reaches standard building regulations (in the UK), there’s very little quality assurance that a finished building matches what was designed at the outset. This means there is an issue of comparing like for like, because if that building was constructed exactly as it was designed it would probably cost slightly more than it did.

Another factor that increases cost is when existing plans are adapted to go down the Passivhaus route, which of course will add extra cost. The best way to approach Passivhaus is to have it as an objective from the very beginning. Take the budget and prioritise how the money will be spent. For example, in order to meet the standard there will need to be triple glazed windows, etc. This way, once the essentials have been priced up, there will be an amount of money with which to work. The building may need to take on a simple but elegant form but it will allow the overall budget to be balanced.

The Air is Too Dry in a Passivhaus – IT DEPENDS

Elrond says that this issue is more complex than it might seem on the surface. For an in-depth answer he suggests reading a paper on Passivhaus ventilation that Mark Siddall wrote for the AECB. However, most occupants are used to living in buildings that don’t perform very well and perhaps have more moisture than would be ideal (which may lead to environments that encourage mould growth and in turn can cause occupant respiratory difficulties such as asthma). In buildings which are built right – high levels of insulation, airtight, well ventilated, etc. – the humidity will definitely be lower in certain circumstances than traditionally constructed buildings. That’s not necessarily a bad thing because a drier building will tend to be a healthier building. If things are not balanced properly or something is not quite right, then it may feel slightly drier than is comfortable.

MVHR is Too Noisy – IT DEPENDS

Careful design and installation should mean that noise from MVHR is not an issue. In a Passivhaus building the MVHR should be in a separate area (like plant room or cupboard) but it can even be outside the building (providing good acoustic separation).

The Passivhaus standard also requires that background noise from MVHR should not be greater than the World Health Organisation‘s recommended noise levels for people to sleep comfortably. It’s also worth noting that the fans are running at an incredibly low speed so there should be very little noise coming from them.

Where there might be the possibility of sound travelling through the ducts from one room to another, there needs to be acoustic attenuation built in, which will eliminate the problem.

MVHR Costs More to Run Than the Energy it Saves – MYTH

Clearly when you move from a house without MVHR to one that does have MVHR, there is a new cost to pay. However, as discussed earlier, it is often difficult to compare like for like between a Passivhaus and a non Passivhaus.

But, so long as the airtightness of the building reaches a certain level (approximately 1.5 air changes per hour), it’s been proven that the amount of energy saved and the cost of that energy saving is much greater than the cost of running the MVHR.

Mechanical Ventilation Has to be Running All the Time in a Passivhaus – MYTH

Elrond quickly shoots this one down by saying that at Architype they design their buildings to use natural ventilation in the summer and MVHR just for the winter months.

It should be easy to tell when to switch off the MVHR. When opening the window, if it feels dramatically colder outside than indoors then a lot of heat energy is being lost and there’s also a cold draught coming in. This would be when you would want the MVHR to be on. Alternatively, when opening the window if the fresh air coming in feels comfortable and there’s no cold draught, then probably you don’t need to have the MVHR running.

Mechanical Ventilation is Too Complicated to Use – MYTH

Elrond argues that this is a myth because the controls are simple to understand with a small amount of training. Most people can operate a boiler, switching off the heating for the summer, for example. Mechanical ventilation is no more taxing.

You Can’t Have a Woodburner in a Passivhaus – MYTH

This is more a case of there’s no need to have a woodburner in a Passivhaus. People often desire them for emotive reasons because it’s nice to sit around a fire or to feel heat emanating from something.

Having a woodburner in a Passivhaus is generally discouraged for a couple of reasons:
- It would only be used for a very short time of the year
- A lot of heat will be generated and that heat will be retained
Passivhaus Will Only Work on a Sunny Site – IT DEPENDS

Passivhaus does optimise the solar gain so as to make the most useful benefit of the heat from the sun. With a small building on a site that gets little sunlight it would be more of a challenge and would really have to be addressed on a specific case by case basis as to whether it was viable or not. As a building gets bigger the parameters change slightly. Elrond uses Architype’s schools as an example. Having more people in a building means there’s more heat energy being generated and so there’s less of a need for using heat from the sun.

Passivhaus is Best Suited to a Domestic Market – MYTH

Elrond wonders whether there might be some confusion in the word Passivhaus (or passive house). One of the reasons the German word is the preferred form is that the literal translation of ‘haus’ means building. In other words a Passivhaus can be any type of building.

Elrond is All Over Twitter!

Follow Elrond Burrell on Twitter

Transcript

Download a transcript of the interview with Elrond Burrell.

UK Passivhaus Awards

Ben shares the exciting news that his production company, Regen Media, is producing video inserts for the UK Passivhaus Awards. This means that very soon you’ll be able to find out why the following projects have made it to the shortlist:

Private Housing (sponsored by Ecology Building Society)
• Crossway, Hawkes Architecture Ltd.
• Plummerswood, Gaia Architects
• Totnes Passivhaus, Passivhaus Homes Ltd.

Social Housing (sponsored by Kingspan Insulation Ltd)
• Ditchingham Passivhaus, Parsons & Whittley
• Lancaster Cohousing Project, Eco Arc Architects
• Racecourse Passivhaus Bungalows, Gentoo

Non-domestic (sponsored by Munster Joinery)

• Green Base, Simmonds Mills Architects
• Canolfan Hyddgen, JPW Construction
• Interserve Office, Interserve

ArchiHaus Granted Planning Approval to Build 150 Passivhaus Homes

Ben also has more good news. In episode 24 he interviewed Jonathan Hines about ArchiHaus and Architype‘s proposal to build 150 houses in Kingstone. Well, not long after the episode was published they received the go-ahead!

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June 18, 2013
HPH023 : A Cottage Built with Structural Insulated Panels (SIPs) – with Kingsley Barraclough (Client Case Study)
Kingsley Barraclough shares his experience of building a house and explains why he decided to use structural insulated panels (SIPs).

Interview with Kingsley Barraclough

Kingsley’s background as a plumber has given him plenty of opportunities to see houses losing heat and that’s why he was determined to build himself an energy efficient home. So, his goal was to create a small, flexible space with lots of natural light, that was easy to run and also cheap to heat. The new cottage would have a floor area of 125m²and be built on a plot beside his existing property.

Despite Construction Experience, Kingsley Chose to be Just the Client!

Although Kingsley’s an experienced plumber he did not do any of the work himself, reasoning that it would not be a good idea to change the dynamic of a team that already works well together. He also hired a project manager because he believed that while he can work in a team, he did not have the necessary skills required to run a team and deal with the many things that can go wrong!

Hiring a Contract Administrator Made Dealings Simple

Kingsley took the advice of his project manager and hired a contract administrator. This effective third party acts as a membrane between client and builder, and provides some neutral ground should any problems arise. Kingsley says that it worked well for both parties.

Initially Kingsley Discussed The Outcomes He Wanted to Achieve with His Architect

Kingsley’s first step was to sit down with an architect and talk through what he wanted to achieve from the new house. Whereas his existing home was from 1884 and had lots of nooks and small rooms, in contrast he was keen to create a more contiguous living space.

The SIPs are Engineered to Suit the Design

Once a design was created and planning permission acquired, Kingsley had to decide on a build method. After researching structural insulated panels as an option and visiting houses that had been built with them, he chose this route. An engineer then reworked the SIPs method of construction to fit with the design. For example, where the timber panels were not suitable the engineer reinforced it with steel construction to achieve the required look. At no point did Kingsley have to compromise with the SIPs.

A Structural Insulated Panel is Like a Sandwich!

Kingsley talks about the structural insulated panels he used which consist of 2 layers of OSB with a core of PIR foam. [An additional 25mm insulation, TW55, was also added to these Kingspan Tek panels on the inside behind the plasterboard lining, which proved very cost effective.] Once machined these panels form part of a kit, which turns up labelled and numbered. There are rebates, grooves and fillers that lock all the panels together.

SIPs are Incredibly Quick to Put Up

With the hard work done in a factory, one key advantage of SIPs is that they can be assembled on site very quickly. In this case, the ground floor was done in the first week and the second floor was done in the second week.

The Precision of SIPs is Greater Than a Conventional Build

Having been in the trade for many years, Kingsley says the nature of block and breeze construction means you tend to work to the nearest inch. However, with SIPs you are working to about 3mm.

SIPs Allow You to Work on Two Faces at Once

Once the timber cell has been put up the services can be going on inside – pipework, electrics, etc. – while brick work or cladding can be underway on the exterior. Wet trades are not crossing paths with the services.

Kingsley Presented His Intentions to His Neighbours

Kingsley wanted his house to be a comfy fit for everyone in the area and so he negotiated with the people either side about the aspect, size of the building, etc. As someone who really values his neighbours, presenting his intentions at every stage of the project worked very well.

The Cladding Needs No Maintenance

Two thirds of the face work is in a cottage mix of bricks (three local bricks that are used randomly) and then one third has got a modern version of weatherboard, which is a concrete board, called Eternit board (made by Marley). It gives the impression of being wood but is good for minimising heat losses and also will never need to be painted.

The SIPs Hold up the Bricks!

Kingsley points out that the brickwork – the face work – is attached to the SIPs with brick ties in the conventional way, so it’s not just held there by gravity. It is secured in the same way that brick to breeze block is secured, but really the SIPs panels hold up the bricks, not the other way around.

Buying Windows From Abroad was Cheaper

Kingsley put a lot of effort into finding window frames. The triple-glazed ones he eventually bought were dramatically less than getting them locally. Kingsley does not understand why this is.

Put Your Money into the Fabric of the Building

After considering many options including Huf Haus, but trying to temper budgets and reality, Kingsley ended up concluding that the money is better spent making sure you don’t need energy than in having very fancy low cost energy. So he put a lot of effort and money into making sure he doesn’t lose heat in the first place (rather than having a cheap source of it).

Minimise Your Dependence on Technology

Kingsley did not invest in heat pumps or other renewables because he thought they were too expensive and he didn’t want to have the worry of maintaining them as he got older. The thought of claiming on warranties of companies in 10 years for £30,000 bits of kit somewhere in the ground was something he wanted to avoid.

The House is a Hermetically Sealed Box

Although the appearance may be conventional, the house is airtight and very well insulated. It uses an air management system (mechanical ventilation with heat recovery) to bring in new atomised air but without the heat losses. 80% of the heat of the expelled air is saved and there is a full air change in the house every hour and a half.

Installing Cabling for PV Means it Could be Easily Added Later

A modern high efficiency condensing gas boiler drives the underfloor heating and the hot water, etc. Plus there is a cylinder that will accept solar and cabling to allow for PV at a later stage. Kingsley has no plans to install renewable technology but if efficiencies continue to improve, he wants to make sure he can add them retrospectively (without having to change cylinders and knock holes in the walls to add wires, etc.).

Coordinating the Utilities Proved Difficult

Although Kingsley could get the gas and water companies to be pretty cooperative, he really struggled with UK Power Networks. Kingsley’s advice, for anybody doing a new build in the UK, would be to get that bit applied for at the same time as you get your planning permission. There is a 90 days notice period, even from when they say yes! And this does not necessarily mean they arrive on the 91st day. So, organising this is a priority because not having electricity reliably is going to be a problem. Kingsley says having a contract administrator really helped.

Life is Much Easier When All The Contractors Want the Same Outcome

Kingsley believes he was very fortunate to have a team that shared his vision and all clicked together. He gives the example how if his interior designer came up with a good idea for the kitchen, the person building the kitchen would readily help to achieve it. There were no hidden agendas.

Having Builders Who Got on With the Neighbours Helped

Kingsley was very pleased with his team and thought it was fantastic to have builders that put themselves out to get on with his neighbours. He says this set the flavour for the build and eased pressure points with parking, etc.

House designed by Martin Roberts from Cubed Projects

Transcript

Download a transcript of the interview with Kingsley Barraclough.

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Elrond Burrell on Home Style Green

Elrond Burrell is a guest on the Home Style Green podcast. He gave a really good explanation of the Passivhaus standard (the comfort standard). Check out episode 30: Is Passivhaus relevant to New Zealand?

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May 22, 2013