Thermal mass

In building design, thermal mass is a property of the matter of a building that requires a flow of heat in order for it to change temperature. Not all writers agree on what physical property of matter "thermal mass" describes. Most writers use it as a synonym for heat capacity, the ability of a body to store thermal energy. It is typically referred to by the symbol Cth, and its SI unit is J/K or J/°C (which are equivalent). Because: Christoph Reinhart at MIT describes thermal mass as its volume times its volumetric heat capacity. Randa Ghattas, Franz-Joseph Ulm and Alison Ledwith, also at MIT, write that "It [thermal mass] is dependent on the relationship between the specific heat capacity, density, thickness and conductivity of a material" although they don't provide a unit, describing materials only as "low" or "high" thermal mass. Chris Reardon equates thermal mass with volumetric heat capacity . The lack of a consistent definition of what property of matter thermal mass describes has led some writers to dismiss its use in building design as pseudoscience.