OTTV CALCULATION
OTTV stands for ‘Overall Thermal Transfer Value’. It is a value that indicates the average rate of heat transfer from the outdoor environment into a building through the building envelope.
The term building envelope refers to the outermost layer of a building. It includes the roof, the walls and windows of all sides.
Heat gain through exterior walls can be broken down into three components:
- Heat conduction through opaque parts of the wall
- Heat conduction through glass windows
- Solar radiation through glass windows