Thermal mass

Thermal mass is the ability of a material to absorb and store heat energy. A lot of heat energy is required to change the temperature of high density materials like concrete, bricks and tiles, they are therefore said to have high thermal mass. Lightweight materials such as timber and polystyrene have low thermal mass.

Probably the simplest form of thermal mass is a concrete slab floor. You can also use concrete blocks, tiles, brick, rammed earth and stone. Three factors determine how good a material is at absorbing and storing heat.

Ideal material for thermal mass is:

• dense and heavy to absorb and store significant amounts of heat
• a reasonably good heat conductor to facilitate heat transferring in and out
• dark in color, has a textured surface, or both to help absorb and re-radiate heat

Links

• Specific heat of solids