High thermal mass, lower summer overheating and low energy demand housing

The architect Stephen Reyburn built a high-mass house in London SW13 ~35 years ago. Mid-terrace, infill. Cavity external walls, concrete floors & stairs. Not dissimilar to Blandford Avenue, possibly a slightly higher thermal capacity.

It had MVHR but was designed mostly for lower space heating bills. Summer comfort as good as an air-conditioned building was an unexpected byproduct. Indeed, they greatly valued the winter thermal comfort and said that this was worth even more to them than the energy savings.

They opened the 1st or 2nd floor windows wide at night in heatwaves to cool the fabric. Operating the MVHR by day and closing windows tended to keep the coolth within the building.

He sold the house in the 2000s so I have no figures for years since. AFAIK the highest temperatures that he recorded within the house in 20 years were 23/24/25 degC on the ground/first/second floors.

The peak temperatures in this house in 2022 were 23.7/24.2 degC on the ground/first floors. But this is a ‘cool summer zone’ compared to London, the SE and E. The external maximum here (Met. Office ‘Hereford’) was ‘only’ 35 degC.

There was possibly more UK attention to cooling of dwellings in 1995 – which had a hot sunny August – than there has been since.



David Olivier BSc MASHRAE


Lower Orchard House

Lyonshall, KINGTON

  1. K., HR5 3LX

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