Harris Academy Sutton (Passivhaus)

Harris Academy Sutton was delivered as a new building on the London Cancer Hub site in Sutton, not as a retrofit of an existing school. The published capital cost is about £40m for the four-storey, science-focused secondary. Because it is a new-build to Passivhaus standard, its relevance to an estates team is as a fabric-first and airtightness benchmark, not as a PSDS decarbonisation grant case.

Adopting Passivhaus is reported to save the school roughly 80 per cent on heating bills versus a conventional building of the same size, through very low fabric heat loss, high airtightness and MVHR heat recovery. This is the same fabric-first logic the worksheet applies when it sizes ASHP capacity from a heat-loss coefficient.

The building was designed by Architype (Passivhaus architects) and built by Willmott Dixon. It forms part of Sutton's masterplan for the London Cancer Hub, a life-science research and education campus, and was designed with a science and STEM specialism including eleven laboratories.

A Passivhaus new-build like Harris Academy Sutton sets the fabric performance a deep retrofit aims toward. It does not tell you retrofit cost directly, but its airtightness and heat-loss outcomes are the target that a fabric-plus-heat-pump PSDS scope is trying to approach in an existing building.