The performance of a well insulated house heated by an air-water heat pump

This paper describes the performance of a highly insulated house operated under simulated occupancy and heated by an air-water heat pump during 1978–80. The house, which was one of four BRE low energy house laboratories, was heated continuously to 20°C.

Although underfloor heating coils were employed. (in order to provide a low condensing temperature for the heat pump) the control of internal temperatures was largely satisfactory being within ± 2°C of the mean value on over 85% of occasions.

The seasonal coefficient of performance of the heat pump for space and hot water heating was 2.3 which in primary energy terms corresponds to a natural gas boiler of about 70% efficiency. The heat demand of the dwelling at ?1°C was 3.8 kW which was close to the expected value and the heat pump required backup heating only during some defrosts. The backup heating system was used in the true supplementary mode only on 2 days during the winter of 1978/79.