There is a direct correlation between outdoor temperature and energy consumption. The number of degree days is a value that determines how often the outdoor temperature is below the heating threshold temperature, the threshold temperature at which heating is usually switched on. This value is given in kelvin and is high when outdoor temperatures remain cold for a long time. In Luxembourg, the index used to determine the heat loss of a building is set at an ambient temperature of 20 °C for a heating threshold temperature of 15 °C.
What is the degree-day principle?
