Heating degree days

The heating degree days index represents a proxy for the use of energy required for heating buildings. It is computed from the outdoor air temperature as the cumulated daily deviation from a base temperature threshold from October to March (see the ETC-CCA Technical Paper for details). The temperature threshold, period and formulation can vary according to the local climate and applications. A base temperature of 15.5 °C is considered here as representative for the pan-European scale and daily minimum, mean and maximum temperature values are used as input variables.