The temperature correction is done in relation to the normal temperature in the municipality. This is done using degree day numbers. The number of degree days is a measure of the need for heating. It is assumed that there is no need for heating when the daily average temperature exceeds 17 °C. The degree day number of a day is defined as the number of degrees the average day temperature is below 17 °C. The energy consumption is temperature corrected by the part of the total energy consumption in the building that is temperature dependent. This is done for each building category based on the ratio between the degree day number in the current year and the corresponding normal (1981-2010), for the municipality in which the building is located. Degree day figures are from Enova.