Sizing of the heating system

Note 1: In the case of very old properties and/or homes with very poor external thermal insulation, it is recommended to increase the calculated power or, more simply, select the next higher power model.

Note 2: For properties built after 1990 and/or with thermal insulation that complies with Energy Performance Certificate (EPC) ratings C or D, the calculated power can be reduced by up to 20%.

Note 3: For properties built after 2005 with thermal insulation that complies with EPC ratings A or B, the calculated power can be reduced by up to 40%, or you may simply select the next lower power model.