Hackbridge Primary Passivhaus

Hackbridge Primary (Sutton) was handed over in 2019 as the UK's first Passivhaus Plus certified school. The Passivhaus Trust case study gives a project cost of about £9m across a 1,865 m2 gross internal floor area (1,510 m2 treated floor area), which works out at roughly £4,800 per m2 gross internal area. That is a whole-project outturn for the 2017 to 2019 build, including site and professional costs, not a construction-only or index-adjusted rate. Because it is a new-build, treat it as a fabric-and-services benchmark rather than a directly comparable retrofit cost.

External-wall U-value below 0.15 W/m2K, roof below 0.10, triple-glazed windows around 0.85, airtightness target below 0.6 ACH at 50 Pa, MVHR with greater than 85 per cent heat recovery.

Published Passivhaus Trust comparators place the Passivhaus capital uplift at 5 to 15 per cent over an equivalent baseline new-build, recovered in lifetime running costs.

Hackbridge's published in-use heating demand is materially below the DfE benchmark for primary schools; with on-site PV it is reported to save on the order of 94 tonnes CO2e per year and export surplus electricity to the grid, validating the fabric-first design-day logic. Detailed monitoring data is in Passivhaus Trust case studies.