U Value Calculations
The U value of a building is based upon the amount of heat lost through its
roof, floor or wall.
• The higher the U value, the more heat will be lost.
• Lower U values are therefore preferable.
• U values provide the data with which carbon or energy reduction in a building is calculated.
Thickness and juxtaposition of building materials are considered. Following this, the specific thermal conductivity of each element should be found. This property is often described as the k value.
The resistance of each building element is calculated using the formula, R = d(1/k), where d is the thickness of the element and k is the conductivity of the material. R is the value which describes the heat resistance of the element.