Insulating Your Home
Calculating Heat Loss
Calculating heat loss requires a U-Value. A U-value is a measurement which indicates heat transmission through thicknesses of materials within a building. Heat loss through a poorly insulated wall or window is a good example.
Lower values indicate better insulating properties. Insulating materials with low U-values help keep buildings warmer in winter and cooler in summer. EPS boards are just one example of insulating materials with very low U-values.
How do you work out U-values?
The U-value indicates how much heat (or thermal energy) is lost or gained through a wall, or other building component.
A building components' heat loss/gain is measured across 1m² of the material. For example a brick wall would have a 1m² section tested. Thermal energy is applied to the test section. The amount of energy required to alter the temperature by 1°C from one surface to the other is measured. This measurement indicates the U-value of the material.
There's some maths involved. The unit for U-values is W/(m²K). This describes how much thermal energy in Watts [W] is transported through a 1m² surface area at a temperature difference of 1 Kelvin [K], or 1°C.
A theoretical U-Value of 0 W/(m²K) would experience no loss of heat. In reality, all materials experience some degree of heat loss.
What is a good U-value?
On exterior facades, a U-value less than 0.3 W/K (m²K) would be deemed to have good thermal insulating properties. The thickness of the material will affect the U-Value. Lower U-values often require thicker insulating materials.