A construction is defined as a type of exterior wall, roof, partition (also known as an interior wall), ceiling, or non-glazed door. Each construction is made up of one or more material types. Each of these material types contain thermal properties, which when combined to create a construction, define the thermal behavior for heating and cooling load calculations.
Each material type contains the following thermal properties:
| Parameter Name | Units |
|---|---|
| Thickness | m |
| Conductivity | W/(m-K) |
| Density | kg/m³ |
| Specific Heat | kJ/(kg-K) |
| Resistance | (m²-K)/W |
Heat capacity (HC) is the ability of a construction assembly to absorb thermal energy. The heat capacity of an assembly is calculated using the following equation:
| Equation N2-1 |
 |
|
|---|---|---|
| where: | ||
| n | is the total number of layers in the assembly | |
|
is the density of the  layer |
|
|
is the specific heat of the layer |
|
|
is the thickness of the layer |
|
| all in constant units. | ||