Post-construction Building Performance Evaluation (BPE)

Space heating for most dwellings constructed to the Future Homes Standard (FHS) will be provided
by an air source heat pump (ASHP). ASHP sizing for new-build dwellings is based on designed fabric
performance. However, growing evidence indicates a performance gap between the designed and as
built thermal performance of new-build dwellings. A performance gap could result in an ASHP being
undersized. It will also increase space heating energy costs, emissions, and demand on the grid.

The Energy House 1 fieldwork team measures the as-built thermal performance of new-build
dwellings to determine whether they perform as designed and identify the causes of any performance
gap. A range of BPE techniques are used, including whole-house heat loss tests, in-situ U-value
measurements, air permeability testing, air infiltration identification, thermography, and ventilation
measurements. Findings are used by housebuilders to inform their design and construction process.

Our research suggests that modern methods of construction (MMC) may provide a more reliable
means of achieving as-built thermal performance that aligns with the FHS specification