The disparity between our buildings’ actual and predicted energy performance is down to a lack of understanding of what causes it
There is a growing realisation that not only do many new buildings not perform in accordance with their design intent, but that the performance gaps between expectation and reality can be huge. For example, it is not unusual for a new educational building to use three times as much electricity as anticipated, and for occupant satisfaction with basic environmental conditions to be poor.
These discrepancies are not new. I and others have been writing about shortcomings in energy performance for more than twenty years , but unfortunately the evidence, which came largely from case studies, was too often dismissed as anecdotal. Now that it piles in from many directions, it can no longer be ignored. However, in spite of all the warnings, it seems to have taken the industry and government by surprise; with some people even wondering in public whether there really is a gap! How out of touch can you be?
Many policymakers seem to think that building performance is largely about construction and regulation, not the consequence of a much wider range of influences
Why has this situation come about? Because neither government, nor the design professions, nor the construction industry have invested nearly enough in understanding building performance. In fact, in recent decades, the amount of feedback to both policymaking and practice has actually dwindled, as an unintended consequence of government outsourcing and privatising its design, research and works departments.
Nothing has properly replaced these formal and informal learning systems, apart, of course from the virtual reality of computer models which often suggest that complication improves performance. In fact, without careful attention to detail, more complicated buildings and systems tend to spread capital costs too thinly and create more things to go wrong.
Many policymakers also seem to think that building performance is largely about construction and regulation, not the consequence of a much wider range of influences, as buildings come into being, change hands, and are occupied and evolve through time. Meanwhile, the construction industry itself designs and builds, but does not routinely follow through into operation, engage with in-use performance, learn from the experience, or close the feedback loop. Instead, the “golden thread”, from client and design intent, through to practical reality, on into operation and back into briefing and design, tends to be chopped up in many places, too often in the name of improving efficiency and cost-effectiveness.
In government itself, the Department of the Environment used to be the focal point for buildings. While it was far from perfect, since the mid nineties many of its tasks have been dispersed to other departments and agencies, with consequent losses in coherence and insight. Policy making has become jumbled-up, not joined-up, not helped of course by the privatisation of the BRE and the loss of other in-house technical skills that once allowed government to be an “intelligent customer”.
The government is prepared to spend many billons of pounds on physical infrastructure. Why can’t it spend a minute fraction of this on a coherent technical infrastructure that can support the creation of a better and genuinely low-energy and low-carbon building stock from our existing and new buildings?
Bill Bordass is a building scientist and founder of William Bordass Associates
See for example M Coomber, Tales of the unexpected, Building, Energy Supplement 38-39 (17 August 1990) and B Bordass, Optimising the Irrelevant, Building Services 32-34 (February 1993).