SR108 Thermal performance of buildings with heavy walls (2007)

Side-by-side test buildings were used to investigate the effect of wall thermal mass on thermal comfort and auxiliary heating energy use. The test buildings were nearly identical apart from the level of thermal mass in their walls. One had lightweight exterior-insulated timber-framed walls and the other had heavy exterior-insulated concrete walls.

The test buildings were monitored over a period of 25 months with four different building configurations tested.

The results show that the heavy walls significantly improved comfort during the daytime and night-time through reducing the frequency of overheating and maintaining warmer temperatures respectively. The heavy walls provided up to 5°C cooling when the buildings were unventilated and up to 3°C cooling when the buildings were ventilated.