Innovate UK’s funded the Building Performance Evaluation Programme over five years: the largest programme of systematic research into energy use in buildings and the ‘performance gap’ so far undertaken in the UK. Cambridge Energy’s team did the analysis work and we looked across all 50 non-domestic evaluation projects funded by Innovate UK over four years, analysed the data emerging, and drew out conclusions that almost certainly apply to other commercial and public buildings. (There were large firms and SMEs among the commercial organisations.) We identified an evidence-based performance gap averaging 3.5 across the non-domestic portfolio – put simply, emissions were 250% higher than designers estimated during design, on average, for commercial and public buildings, and sometimes considerably higher.
We went on to do similar performance analysis and diagnostics work on the domestic portfolio (76 projects, comprising 300+homes), and found that even simpler domestic buildings still fall a long way short of design estimates, with a typical new home emitting 2.5 times more carbon (150% more) than the design estimate.
It is hard to generalise across all projects, but the programme generated important insights into where even buildings where the project team prioritises carbon performance can falter. Procurement, commissioning and handover are at least as problematic as the technical side of low carbon design.
CE’s Jason Palmer was also an ‘Evaluator’ for the Building Performance Evaluation Programme. He helped monitoring teams get to grips with energy data for their buildings – along with data about thermal performance, occupant satisfaction, air-tightness, lighting, embodied carbon and other measurable outcomes from building projects.