The increasingly high temperatures that are expected due to climate change made summer overheating a potential problem.  Approved Document L requires the designer to consider approaches to limit the effects of heat gains in summer.

Thermal mass is recognised as one means of achieving this. In a masonry build, the overall temperature will be cooler as the masonry blocks absorb heat in the daytime and release this stored heat during cooler night-time periods.  Summer overheating is a problem typically associated with lightweight frame building systems.

Houses with higher mass also have a beneficial effect on the heating pattern in winter.  By offering good thermal insulations, thermal inertia and airtightness properties, aircrete reduced extremes of internal temperature, keeping it at a more consistent level.