Mr. Tom Ellis
asked the Secretary of State for Energy if he will publish a list in order of thermal efficiency at the point of consumption of the main forms of domestic space heating and of domestic water heating.
§ Dr. John A. Cunningham
Domestic heating efficiency at the point of consumption varies substantially according to type, manufacturer, age, method of installation and use, so that it is impractical to generalise. Furthermore, efficiency values on their own give a false impression of the cost and suitability of a heating system, which also depends on the initial cost, the type of 239W dwelling, level of insulation, the price of delivered fuel or energy, the pattern of consumption, method of control, etc.
However, modern well designed and carefully controlled heating systems,
Per cent. Space heating … Electricity … Radiant and convector space heaters 100 Storage heaters 80–90 Gas … Radiant/Convector fire 50–60 Convector (balanced flue) 65–70 Central heating boiler 60–70 Oil … Central heating boiler 60–70 Solid fuel … Open fire 25–40 Open fire with back boiler 35–50 Room heater with back boiler 60–70 Central heating boiler 60–70 Water heating … Electrical … — 75 Gas … The efficiencies quoted refer to a variety of appliances. 40–55 Oil … 40–50 Solid fuel … 40–50
It should in addition be pointed out that the above thermal efficiencies do not include the efficiency of production, conversion and distribution of domestic fuels and energy up to the point of consumption, which varies widely between some industries.