Reducing heating costs is an important concern for householders, but many conventional methods of cutting down heating costs, such as insulating lofts and cavity walls and fitting double glazing, involve considerable capital outlay. An effective way of reducing heat losses with a minimum of capital outlay is to fit reflecting metal foil behind the central hearing radiators, but little has been done to measure the amount of energy saved in this way. Similarly, a foil layer can be used to reduce heat losses fi om beneath suspended floors, but little data are available on its effectiveness, Work is reported here on experiments carried out in an environmental chamber to measure the effect on heat losses of metal foils behind radiators and beneath suspended floors. Reductions in the overall energy consumption of the room of up to 6% were recorded by installing foil behind a radiator, while the heat loss through the area of wall immediately behind the radiator fell to less than 30% of the original value. The heat loss from a suspended timber floor was reduced by up to 48% when foil was applied to its under surface.