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.
Insulation products come in two main categories — bulk and reflective — which are sometimes combined into a composite material.
To compare the insulating ability of the products available, we need to look at their R-value, which measures resistance to heat flow. The higher the R-value, the higher the level of insulation. Products with the same R-value have the same insulating performance if installed as specified. Check the information supplied on the product, including the R-value, the price per square metre and whether it must be installed professionally or can be DIY — some types of insulation require the use of masks and protective clothing.
Ask if performance guarantees or test certificates are available. All insulation materials that are sold in Australia must meet Australian Standard AS/NZS 4859, materials for the thermal insulation of buildings, even if they are imported. Compare the environmental benefits of different products. Ask about recycled content and how easily the product can be recycled after use. For example, some brands of glass wool, polyester and cellulose fibre insulation contain significant amounts of recycled material. The appropriate degree of insulation depends on climate, building construction type, and whether auxiliary heating and/or cooling is to be used
Insulation types and their applications
mainly resists the transfer of conducted and convected heat, relying on pockets of trapped air within its structure. Its thermal resistance is essentially the same regardless of the direction of heat flow through it. Bulk insulation includes materials such as glass wool, wool, cellulose fibre, polyester and polystyrene. All bulk insulation products come with one material R-value for a given thickness.Bulk insulation traps air in still layers.
mainly resists radiant heat flow due to its high reflectivity and low emissivity (ability to re-radiate heat). It relies on the presence of an air layer of at least 25mm next to the shiny surface. The thermal resistance of reflective insulation varies with the direction of heat flow through it. Reflective insulation is usually shiny aluminium foil laminated onto paper or plastic and is available as sheets, concertina-type batts and multi-cell batts. Together these products are known as reflective foil laminates, or RFL. Dust settling on the reflective surface greatly reduces performance. Face reflective surfaces downwards or keep them vertical. The anti-glare surface of single sided foil should always face upwards or outwards.