Post-occupancy evaluations show our buildings are not as green as design predictions – something needs to change

If you bought a new car on the strength it did 60 miles to the gallon but only got 20, you would expect it to be fixed or get your money back. But when it comes to gas-guzzling buildings, people get much less worked up. Evidence shows that new buildings regularly consume two to three times as much energy as the design prediction, a figure borne out by our two post-occupancy evaluations in this week’s issue. In both cases design teams defended themselves by saying major components had failed, and buildings take time to tune up and start working properly.

Granted buildings are bespoke and more complex than the average car but bar fine-tuning after handover, building owners rightly expect their building to perform near the design prediction when handed the keys. Most don’t have the luxury of having the time or money to carry out post-occupancy monitoring. Something needs to change.

Every building should have a commissioning plan to ensure that complex systems run properly, and in harmony, to deliver low running costs. And buildings need adequate meters, checked and calibrated - if building owners don’t know how much energy each system is using they can hardly be expected to spot any problems. Building users in naturally ventilated buildings have be taught what to expect from it and when it is actually more efficient to close all windows and switch on mechanical systems. Finally project teams need to offer ongoing technical support to keep an eye on performance and fine tune systems.

Most of this is already embodied in Soft Landings, a process where project teams work with clients to define what they want, then ensures this happens onsite and beyond. The trouble is current forms of contract militate against the collaborative nature of Soft Landings. One of the recommendations of Paul Morrell’s IGT report was for Soft Landings to be embedded into public sector contracts, an idea that should be taken up by the Green Construction Board. Unless we get to grips with poor building performance, the drive towards zero carbon buildings is little better than wishful thinking.

Thomas Lane, assistant editor