Insulation acts as a barrier to heat flow and is essential for keeping your home warm in winter and cool in summer. A well-insulated and well-designed home provides year-round comfort, cutting cooling and heating bills by up to half. This, in turn, reduces greenhouse gas emissions.
Climatic conditions influence the appropriate level and type of insulation. Establish whether the insulation is predominantly needed to keep heat out or in (or both). Insulation must cater for seasonal as well as daily variations in temperature (see ‘Insulation levels for your climate’ below).
Typical heat losses and gains without insulation in a temperate climate.
Use passive design techniques 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 also important, as draughts can account for up to 25% of heat loss from a home in winter (see Passive solar heating; Passive cooling; Sealing your home).
Insulation can help 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 retrofitting insulation, see ‘Adding insulation to existing buildings’ below.
Most common construction materials have a low insulating value, but some require little or no additional insulation. Such 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. Under the Building Code of Australia (BCA), the required total R-values for the building fabric vary depending on climate zone (see Design for climate) and the building site’s height above the Australian Height Datum. Ensure you comply with the BCA requirements for energy efficiency of building fabric.