Heating Degree Days (HDD) are a measure of how much (in degrees Celsius), and for how long (in days), outside air temperature was lower than a specific “base temperature” (or “balance point”). They are used for calculations relating to the energy consumption required to heat buildings.

Cooling Degree Days (CDD) are a measure of how much (in degrees Celsius), and for how long (in days), outside air temperature was higher than a specific base temperature. They are used for calculations relating to the energy consumption required to cool buildings.

You will need to go through this process for both Heating and Cooling degree days. Getting an average temperature over the last 5 years from Degreedays.net and inputting that value into the EST.