The seasonal space heating energy efficiency η_s shall be calculated as the seasonal space heating energy efficiency in active mode η_son, corrected by contributions accounting for temperature controls, auxiliary electricity consumption, standby heat loss, ignition burner power consumption (if applicable) and, for cogeneration space heaters, corrected by adding the electrical efficiency multiplied by a conversion coefficient CC of 2,5.

The annual energy consumption Q_HE in kWh in terms of final energy and/or in GJ in terms of GCV shall be calculated as the ratio of the reference annual heating demand and the seasonal space heating energy efficiency.