Keep warm without waste

Press, 30 June 1983, Page 12

Keep warm without waste

In winter comfort levels need to be maintained by home heating.

The Home Science Information Service offers some insights into home heating and insulation for warmth without waste this winter.

In New Zealand the majority of homes (73 per cent at the 1981 Census) use electricity with or without other fuels for heating. Nearly half use wood, coke or coal and only 5 per cent use gas, oil or kerosene either alone or in combination with other fuels.

The same census figures show that slightly more than half of the dwellings had insulated ceilings, and of these only 31 per cent had insulated walls.

Keeping the warmth in is the key to preventing waste. About 45 per cent of heat energy requirement is saved by roof insulation. It is well worth while insulating the ceilings, especially those in the major living areas of the house — and worth considering insulating those of the bedrooms for elderly

people or young infants. It is not commonly realised that this insulation makes unheated room temperatures comfortable for a further 10 to 20 per cent of the year — simply because the insulation traps in heat created by people, cooking, the hot water cylinder, lights, and television. This can mean a significant increase in the number of days no heating is required. Windows can also waste warmth.

The heat loss through a single pane of glass is three times that lost through an uninsulated wall.

Medium-to-heavy weight curtains with a close woven lining can reduce heat loss by as much as 40 per cent. They provide nearly as much insulation as double glazing. Drapes also allow the glass to admit warmth — north-facing windows can collect as much as 3 to 4kW of energy per square metre on a clear, windless day.

It is important that drapes are full, with a good

centre overlap and touch either the window ledge or the floor. A closed pelmet at the top prevents cold air circulating. Draughtproofing of doors, windows, floorboards, unused fireplaces and attics keeps in warmth. However, some ventilation is essential or condensation may become a problem. The form of heating chosen is often dictated by that available in the dwelling. It is a matter of making the most of what we have.

As a guideline to economy in fuels, the Home Science Information Service at the University of Otago compared the cost per useful therm of electricity, coal and gas (Dunedin, May 1983). The most economical fuel was electricity on storage heating tariff, followed by electricity on normal tariff, coal in a convector fire, gas, oil and the least economical coal on an open fire. The rate of burning cannot be controlled on most open fires. This, and the

heat loss up the chimney, account for coal on an open fire being less economical than other forms of heating. Common sense can aid economy. Insulation has already been considered, but it is worth emphasising that curtains and draught stops need to be used to minimise heat loss. Use this insulation to maintain normal comfort levels rather than increasing room warmth. Because people are poor regulators of comfort levels this is best done automatically, using remote thermostats and time switches. These aids are a worth while investment. The time switch can be used to reduce heating before you leave the room. “Warmth without Waste” is a leaflet which offers insights into home heating and insulation. It costs sl.oo> posted from the Home Science Information Service, University of Otago, P.O. Box 56, Dunedin. Don’t let an unexpectedly high heating bill wreck the household budget.