Passive design techniques should be used in conjunction with insulation. For example, if insulation is installed but the house is not properly shaded, built up heat can be kept in by the insulation creating an ‘oven’ effect. Draught sealing is important, as draughts can account for up to 25 per cent of heat loss from a home in winter.

Insulation can assist with weatherproofing and eliminate moisture problems such as condensation. Some types of insulation also have soundproofing qualities.

The most economical time to install insulation is during construction. For information on retro-fitting insulation, see ‘Adding insulation to existing buildings’.

There is little insulating value in most common construction materials, but there are some exceptions where little or no additional insulation may be required. Suitable materials include aerated concrete blocks, hollow expanded polystyrene blocks, straw bales and rendered extruded polystyrene sheets. Check with your local building information centre for more details.

Total R-values for roofs, ceilings and floors may provide only one value for total thermal resistance of construction which may not be adequate to achieve compliance with the Building Code of Australia (BCA) requirements for energy efficiency of building fabric.

Under the BCA, total R-values of the building fabric vary depending on climate zone and the height above the Australian Datum at the location where the building is to be constructed.