Ramboll analysis finds endemic “over-design” of UK buildings

Commoditised or ‘play it safe’ design in the UK is regularly resulting in new buildings being constructed with building systems that have 50% more electrical capacity and 30% more heating and cooling capacity than is ever needed, a Ramboll-led study has found. 

Ramboll experts have calculated that, when applied to the 11.8 million sq ft of offices currently under construction in London alone, this over-design is costing the UK £70m in capital expenditure and 23,000 tonnes of CO2 per annum – bad news for both the bottom line and the planet. This is based on estimated achievable savings to be in the region of £60/m2 in cap ex and up to 50% in both energy savings and carbon emissions.

Ramboll’s analysis showed that often this is down to the industry over-designing in its efforts to achieve technical compliance and adhere to current codes and guidance, inadvertently resulting in excessive building system capacity due to a significant gap between predicted performance and reality. 

In addition, pressurised consultants commoditising and re-using ‘safe’ designs, compounded by a procurement system that stifles innovation by focusing overwhelmingly on price, is adding to this inefficiency. 

In working to deliver leaner designed buildings, Ramboll has been applying lessons learned from engineering in extreme environments. Working together for the first phase of the Rothera modernisation project, Ramboll and the British Antarctic Survey developed a design that targets a reduction in energy consumption by up to 35%. To support this, they developed a parametric modelling tool called the evolutionary energy solver that processes millions of possible scenarios and mimics nature to identify the combination of inputs that will provide the best performing, or ‘fittest’ solution. This reduced the time needed to identify these ‘fittest’ solutions by 88% and demonstrated that all possible solutions had been considered holistically.

Mathew Riley, UK managing director at Ramboll, commented: “Over-design is wasting capital investment for building owners and driving higher energy consumption for building occupiers. Nobody wins. The key to efficient design is to really understand how a building will perform, by simulating its operation early in the design development, allowing more informed decisions to be made. At Ramboll we learned from our work, engineering buildings in extreme environments such as the Antarctic, methods that we are now working to apply back into the UK so that we can deliver leaner and greener systems.”

Riley said that the industry needed to “break free from outdated delivery models and conventional thinking”. “By embracing data driven design the industry can reduce capital expenditure, cut carbon emissions, reduce energy consumption and deliver leaner and more sustainable buildings,” he said.

Ramboll’s analysis is based on the studied operational energy performance of over 100 commercial properties, using real life data.