Insulation products come in two main categories — bulk and reflective — which are sometimes combined into a composite material. For the many different products available see ‘Insulation types and their applications’ below.
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. Ensure that it suits your particular application and fits within the space available. 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. Contact the manufacturer or industry association to find out more.
The appropriate degree of insulation depends on climate, building construction type, and whether auxiliary heating and/or cooling is to be used (see ‘Insulation levels for your climate’ below).
The BCA sets out minimum requirements for the R-values of materials used in the construction of buildings. For reference, see BCA 2013, Volume Two, Part 3.12. It is generally advisable to exceed these for greater comfort and energy savings.
The higher the R-value, the better the thermal performance.
Material R-values are supplied with bulk insulation and refer to the insulating value of the product alone. The higher the R-value the better the thermal performance.
Total R-values are supplied with reflective insulation and depend on the product being installed as specified. R-values can differ depending on the direction of heat flow through the product. The difference is generally marginal for bulk insulation but can be pronounced for reflective insulation.
- ‘Up’ R-values describe resistance to heat flow upwards (sometimes known as ‘winter’ R-values).
- ‘Down’ R-values describe resistance to heat flow downwards (sometimes known as ‘summer’ R-values).
Up and down R-values should be quoted when installing reflective insulation in roofs, ceilings and floors.