Much has been said in recent years about the benefits of thermal mass in building. Scott Clarkson sheds some light on whether too much can help or hinder building performance, with thanks to FWPA.
Like our bodies, building materials have the ability to absorb, store and release large amounts of thermal energy without altering their temperature greatly. We refer to this capability as thermal mass and, if used correctly, it can provide an effective means of moderating daily temperature changes, greatly reducing the need for artificial heating and cooling.
However, there can always be too much of a good thing. Although design guides and legislation encourage the incorporation of thermal mass to enhance thermal comfort in homes and buildings, there is actually little quantified information to help designers calculate how much mass is needed.
Too much thermal mass can actually reduce thermal comfort and increase energy usage. Because the manufacture of high thermal mass material often comes at a high environmental cost, and especially if a building’s lifespan is short, it’s quite possible that the energy saved can be significantly less than the energy invested in the thermal mass.
It’s important to recognise the variables that influence how thermal mass can be effectively used. The quantity of mass that is useful in a building will depend on key factors such as the local climate, the size and occupation patterns of the building, the environmental design strategy employed, and even the size of windows. Understanding how much thermal mass should be included in a building is important enough, but it’s even more important to understand how to use it in relation to all these factors.
Knowing how thermal energy is transferred helps us determine how to use it. Just like the human body, thermal environments transfer energy through radiation, conduction and convection. Read more