Division 2.1 Label 1 United Kingdom Original text. Later amendments are not shown. 2.1.1Boiler combination heaters in seasonal space heating energy efficiency classes A++ to G and in water heating energy efficiency classes A to G 2.1.2Heat pump combination heaters in seasonal space heating energy efficiency classes A++ to G and in water heating energy efficiency classes A to G ← Division 2 Division 2.1 Division 2.1.1 →