WINTER WARMTH, SUMMER COOL

Press, Volume CV, Issue 31057, 12 May 1966, Page 13

WINTER WARMTH, SUMMER COOL

Heating and insulation go hand in hand. It is not much good spending a lot of money on warming a house if the heat is lost as soon as it is generated. . New Zealand fuel is so cheap and plentiful that there is no point in building thermal insulation into a house.

The purpose of thermal insulation is not primarily to keep people warm but to enable them to enjoy satisfactory warmth at less cost; to use the heat generated in their heating units in the most efficient way possible. Cold Houses Modern houses are notoriously cold houses. They have thinner walls than traditional uses of the 19th century and they have a much greater expanse of glass. Building practices common since 1940 appear to have been introduced without adequate consideration of the effect of climate upon them. Many modern houses are not only cold compared with their predecessors; they are also damp and more draughty.

bad dispersers of space heat. It is probable that twothirds of the heat in the average house that is not thermally insulated escapes up chimneys, through walls, windows, doors, ceilings, floors and roof. As a result, fuel bills can be 60 per cent higher than they need be, and money spent on new heating equipment is more or less wasted.

ceiling insulation comes in flexible rolls or in various sizes of building bats which can be fitted into cavity walls between the studs. There are other filling materials for walls and ceilings besides fibreglass—a chemical wood-pulp material called insulfluf, for example, a very light and fluffy substance with marked fireretarding and sound-insulat-ing characteristics. Applied professionally, this material is usually sprayed over a ceiling with a blower until it fills the space between the joists to a depth of four inches. Another material, expanded polystrene, is used for insulating ceilings and walls. So, too, is the material called perlite, a volcanic silica which is mined in the Rotorua-Taupo region. It has a low thermal conductivity, is extremely light (looking like sand but weighing only a twelfth the weight of sand) and when mixed with cement it makes a concrete that floats on water.

If someone is installing a heating system, part of the capital cost should include a sum spent on preventing heat loss.

At night it is always possible to reduce heat loss by using thick curtains over the windows.

Walls can be effectively insulated against heat loss by a variety of insulating materials, among them fibreglass made from glass fibres so microscopic that it takes 625 fibres to make up a cubic inch. The material looks and feels like crisp cotton wool. It has low thermal conductivity and is non-combustible, an important consideration in a wooden house. Fibreglass for wall and

It has been discovered, for example, that 15 per cent of the heat that escapes from a modern house is lost through the floors, 20 per cent through the windows, 25 per cent through the external walls and 40 per cent through the ceilings. Ceilings, in fact, are very

Perlite can be used as loose fill in the ceiling by spreading sealed plastic bags

containing the material between the joists. For wall insulation with this material there are plaster boards, about an inch thick, made with perlite and gypsum, and for floors a perlite concrete that provides more insulation than 20 inches of ordinary concrete. Reflect Heat Widely used for heat insulation in homes and commercial buildings are the laminated aluminium foil materials that reflect heat One of them, marketed under the name of Sisalation, consists of a layer of reinforced sisal, kraft paper and bitumen that has been bonded on one or both sides with a sheet of highly burnished aluminium. Sheets of this laminated material have great strength and toughness, permitting them to be tacked down over the ceiling joists or, if the house is under construction, by running them over the rafters just underneath the tiles. Sisalation is equally suitable for wall and floor insulation.