Although the term ‘thermal mass’ is not commonly used, there are many examples where we experience it and appreciate its benefits. The most impressive is the ocean: in winter, when there is less sunshine and the average air temperature is low, the water is chilly and only the tough ones might enjoy a swim! In spring, the sun will slowly heat up the water so that finally in summer it will have a comfortable warm temperature. Water has a great capacity of storing heat – it will stay constantly warm during day and night, and even in winter, it can be significantly warmer than its surrounding air temperature due to its ability to absorb solar energy. Water demonstrates the principle of thermal mass. How does it apply to construction?
Thermal Mass, Why Is It So Important for Construction?
Thermal mass is the ability of storing and releasing heat to help retain a constant indoor temperature. It is an effective way to improve thermal comfort in a building and plays an essential role in saving energy. Thermal mass inside a building will absorb heat when the surroundings are warmer than the mass, will store the heat and radiate it slowly when the surroundings are cooler. It can actively be used to regulate temperature, therefore, reducing the need for mechanical heating and cooling. Heavy materials, such as concrete and brick have great thermal storage capacity, whereas lightweight construction materials, such as timber and insulation cannot store heat. Generally speaking, the heavier a material the better its ability to store heat.
When you are building a house following passive solar design principles thermal mass is crutial for the performance of you home. However, if you are folling passive house principles suddenly thermal mass is not as important anymore.
If you want to know more about thermal mass please also read our further articles about this subject.