Wrapping up heating costs

Press, 27 April 1989, Page 33

Wrapping up heating costs

Keeping warm and comfortable while reducing heating costs makes sound economic sense. Realising this cosy concept can be achieved by insulating the ceiling, walls and floor of your home. Insulation works by trapping warm air inside the house like a thermal envelope, so less energy is required to heat it. Eventually insulation costs will be recovered, depending on the climate and the amount of heat needed. Insulating new buildings is compulsory; alterations of existing buildings could provide the opportune time for installing insulation. Houses lose heat in all directions, but because heat rises, more is lost through the ceiling and roof than through the floor.

In winter the inside surfaces of uninsulated walls, roofs and windows are several degrees colder than insulated walls. If you stand close to a cold wall, you will feel cold because heat is lost to it. Heat always flows from hot to cold. If you make the room hotter to compensate, the walls will still stay cold. Insulation warms them up and eliminates this “cold wall” effect. A house with ceiling insulation requires only 75 per cent as much heat, a house with ceiling and floor insulation 50 per cent and a house with total insulation with heavy drapes over the windows only 25 per cent as much heat as an uninsulated house, according to the Building Research Association of New Zealand. Most heat escapes through the roof, so this should be the starting point for insulating a house. Usually this can be easily done. Insulating the floor is a good idea if access is easy. The material is cheap to buy, though placing it may be timeconsuming. Insulating the walls of existing homes is difficult, but should be done if internal linings are being replaced. It is possible to pump a substance into the walls of existing homes.