It is Saturday June 12th 2025 and we are in the middle of a heat wave!
What the pieople living in these flats must be going through is quite frankly unimaginable Sweat – sweat -sweat
What is Thermal Mass?
Thermal mass can be considered to be the capacity of a material to absorb or radiate heat. High thermal mass materials like stone or concrete are always very dense and have high heat conductivity. That is why those old farmhouses with very thick walls are always cool in summer. Furthermore they absorb heat as well and so when the heat is turned off in one of these buildings it takes a long time to cool down.
Timber frame buildings have very little thermal mass and that is why they are so uncomfortable to live in during heat waves.
Surprisingly, there is also very little thermal mass in a conventional cavity wall built home, because the heavy brickwork is outside of the insulation in the cavity and the inner skin has to be lightweight blockwork with very low thermal mass but is needed for the insulation it provides.
In contrast the concrete in an ICF house is surrounded by insulation and is perfect for providing Thermal Mass.
Furthermore, when we design dwellings we provide even more thermal mass by making sure that the floors are concrete as well. !!
The other primary advantage of high thermal mass is that its slow absorption and radiation of heat makes a building with high thermal mass very suitable for heating by an air source heat pump simply because they provide heating and cooling slowly. In effect, the high thermal mass materials act as a store of the heating or cooling, provided by the heat pump.