Heat requirements and energy use in British houses

Abstract

Housing data likely ranges of insulation levels are combined to give estimates of the heating requirements for conventional houses and small flats to be built in Britain in 1977–1987. After allowance for non-solar heat gains, requirements of 65–120 kWh/day for 4–6 person houses and of 8–47 kWh/day for small flats are predicted. The 65 kWh/day lower limit for houses will be improved on in the case of very well insulated houses using modified construction techniques. Data are collated showing average incidental heat gains from appliances, water heating, and other sources. The effects of these on annual heating energy use and on mean power requirements are assessed, and annual heating energy use per kW of design heat loss is calculated for a range of levels of incidental gains at three British locations; Pembroke, Croydon and Edinburgh. The typical solar contribution to this heating energy is also calculated. Mean-to-peak power variations are considered, showing that on average a heating system operates at 20–30% of the house design heat loss; this is the level at which energy use efficiency is most significant. The theoretical predictions of heating energy use are shown to give reasonable agreement with actual use as measured in field trials, despite the wide variability of the latter. The variation of total solar heating with orientation of a house with windows on two opposite sides is studied in the Appendix, showing a variation of ±15% in winter and ±6% in spring and summer for a particular house design.