21. 12. 2015

If Volkswagen Built Homes ...

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The Scandal of the Performance Gap in the Housing Industry

Many people driving a new car have long suspected that the fuel consumption demonstrated in the manufacture’s brochure is significantly out of line with the reality of the day to day running of the vehicle. And then, just a few weeks ago, it was revealed that Volkswagen had installed ‘defeat devices’ in millions of new diesel vehicles to ensure false results from emissions tests. It’s now known that their engines were emitting nitrogen oxide pollutants up to 40 times above what is allowed in the US.

On the 16th November, Louise Ellman, Chair of the Transport Select Committee, said: “The VW scandal has raised serious concerns about whether vehicle type approval testing is fit for purpose. We heard evidence that the gap between emissions detected in test conditions and those detected in the real world is significant. The procedure is clearly inadequate.” Hopefully, VW will now get its full come-uppance in terms of fines, compensation to individual owners, and ongoing reputation damage. It deserves nothing less.

But here’s a thought: what if the same scrutiny were to be applied to the homes we live in? I suspect the vast majority of owners and occupiers would be shocked to discover that there is also a huge gap between the theoretical performance (approved when the house design is authorised by Building Control) and the in-use performance when it comes to actual running costs, carbon emissions and energy bills that you end up paying.

The LABC (Local Authority Building Control) and the Good Homes Alliance report that it is common for underperformance to be around 30% – 40%. This is already a very large discrepancy, but research data from Leeds Metropolitan University (now called Leeds Beckett University) suggest that there are cases where buildings consume 70% more energy for space heating than predicted at the design stage. Anna Timms from the Guardian summed it all up nicely with a tweet on Sunday 15th November “Fancy a new-build home? You get more protection buying a tin of baked beans.”

We can’t just dump all the responsibility here on housebuilders; occupiers of new homes can often be very cavalier in the way they ignore or override energy control systems. But ongoing research continues to identify lots of issues that arise with design, product specification and construction.

For one thing, UK buildings are designed to comply with building regulations (ie, it is the theoretical performance and design that is approved by regulators) rather than being tested after they are actually built. Even sustainability tools such as the Code of Sustainable Homes reinforce a tick-box approach, without really driving a quality assurance process that would be forensically focussed on the fabric of the building.

In other words, it’s a bit like estimating the mpg or emissions of cars from design manuals, and never looking any deeper: if we did this for cars, VW wouldn’t have even needed to bother fixing the tests! In the construction industry, builders have virtually no incentive at all to build to the standards they promise in their plans, and zero fear of ever being found out and appropriately sanctioned.

The Good Homes Alliance suggests that monitoring and post-occupancy evaluation (POE) are essential tools to ensure that low-energy homes are operating as designed, and are comfortable and healthy. Currently, the building regulations only require minimal post-occupancy evaluation, and so most evaluations are undertaken mainly for research purposes.

However, if post-occupancy evaluation is to become a more essential component of sustainable housing development, we have to face up to some issues – as were surfaced recently in a study commissioned by housing developers Igloo in association with Nottingham University:

“POE, however, is not easy and it is not cheap. It can require a plethora of sensors, wires, questionnaires and visits from geeky types. It is time-consuming, and, in market housing, is reliant on the goodwill, patience and co-operation of the home’s owners/occupiers – who can, of course, change over the course of a study. Furthermore, by uncovering gaps in performance, the results of POE can bring a potential headache to developers who then have to explain to customers why their home isn’t working as well as it should.”*

All good points, and that’s just looking at energy performance alone. Alarmingly, the performance gap is not restricted to energy. Two reports published in September have highlighted further risks to health and comfort.

The first is a ComRes survey of 1,005 Londoners undertaken by WSP Parsons Brinkerhoff. The survey highlights Government figures stating that 2000 deaths are already caused by overheating every year – and overheating is caused by poorly designed houses and lack of attention to detail in the design and construction process. In other words, by the lack of building physics.

This isn’t an issue confined to a few properties. The survey reveals that 83% of Londoners surveyed suffered from overheating in their homes this summer, and 31% felt unwell or tired as a result. Death is an extreme outcome: quality of life suffers much more widely from poor air quality and poor quality buildings. The report concluded that if our approaches to building design and construction (and, by the same token, regulation) are not changed now – if we don’t listen to our building physicists – these impacts will worsen, productivity will decline, energy consumption will increase, and the long-term value of homes will be affected.

This research is backed up by the Zero Carbon Hub, which launched an ‘Overheating and Ventilation in Homes’ project earlier this year after stating that “there appears to be growing evidence of overheating in homes, including in homes built or retrofitted to satisfy more demanding standards of energy efficiency.”

The second article summarises a report by Professor Hazim Awbi, Professor of the Built Environment at Reading University (via Guardian). This report predicts that by 2050 – the date by which Britain is supposed to have achieved an 80% cut in carbon emissions – declining indoor air quality could lead to:
• An 80% rise in the 5.4 million people already suffering from asthma;
• Concentrations of volatile organic compounds being 60% above the World Health Organisation 24 hour limits;
• Nitrogen dioxide levels rising to 30% above the WHO’s limits.

These would be very serious consequences. However, they’re not at all that difficult to overcome if we were prepared to introduce minimal incentives for builders, particularly in terms of paying attention to detail on building sites themselves. As Matthew Rhodes, Managing Director of building physics specialists Encraft, has said: “…. the tragedy is that these are consequences which are relatively straightforward to avoid, at relatively low cost, by applying the principles of building physics. Regulatory regimes which focus on in-use testing rather that design evaluation should also be cheaper and simpler, and are fundamental to driving this kind of change”.

The facts are clear: UK building regulations are not delivering homes that perform in use in the way they should. We make this problem much more challenging by trying to predict and regulate energy performance from plans. In the same way that it is far easier to measure the emissions of a VW by sticking a probe up the exhaust, it is much more effective to test the energy performance of a house by looking at the meters, whilst recognising that ‘householder effects’ (in terms of use of appliances and so on) have to be properly taken into account.

And it certainly wouldn’t be necessary to monitor each and every new home. If housebuilders were required to monitor, say, one home in 500, this would still drive an enormous amount of learning in what is currently a pretty barren field of knowledge – and simultaneously get manufacturers to understand much more about how well their products are performing.

We must also ensure that we do not drive energy efficiency without any concern for consequences. There needs to be a fundamental re-think of how both new and retrofitted homes are tested, and this will drive a transformation in the way they are designed and delivered. The process has to deliver adequate air quality and healthy environments, minimise overheating risk and, in addition, optimise energy efficiency.

The Zero Carbon Hub commenced a Government-funded study in early 2013 to review evidence regarding the significance of the performance gap, to explore reasons for it, and set out proposals to address the issues identified. (It was not tasked, incidentally, to look at the health issues referred to above.) In its End of Term report published in July 2014, a ‘2020 Ambition’ was set out, namely: “From 2020, to be able to demonstrate that at least 90% of all new homes meet or perform better than the designed energy / carbon performance.”

A laudable ambition, but one that will not be achieved without the introduction of better standards, driven by proper testing, and rigorous regulatory regimes. Regrettably, the industry itself has very little interest in closing the performance gap, and guess what this current Government’s thinking about the role of regulation is in matters such as these – even smart, cost-effective regulation?

There is therefore zero chance of the UK meeting that 2020 Ambition – yet another consequence of this Government’s utterly deplorable approach to energy efficiency and demand management as critical aspects of a low-carbon economy.

*TSB study, Nottingham University
 

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Comments

11. 05. 2016
Chris Witte

Agree wholeheartedly with the thrust of this article. Why not pay 6 new home owners (one from each of the largest UK house builders ) to have the monitoring equipment installed to disaggregate human behaviour from overall energy efficiency performance and turn the results into an energy wasted vs building regs cash figure. Multiply by ten years ( or 50?). Sell the concept to a TV documentary producer and get them to ask the chief execs of these house-builders for the money back. They can also be asked about what provisions they are making in their accounts for this massive legacy issue their businesses face.
Consumer alarm is the only way to drive change where vested interest is so powerful

24. 12. 2015
George

Mark Siddall of Leap architects has done a lot of work on this area and has recorded his thoughts on this in some detail. You can hear these on Youtube if you search for "If Volkswagen made houses"

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