Home Insulation Buying Guide

The government's home insulation bungle has demonstrated the importance of knowing what's what.
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04.Before you insulate/Tips

Judging from some subscribers' reports about installation, expect anything from a fantastic to a horrendous experience.

Here’s what to look for before you leap:

  • Be clear about what you’re trying to achieve. For example, the major cause of a hot home could be unshaded windows, so installing shading will be just as important as insulation.
  • Consider where you’re going to insulate — in existing homes, it’s usually the ceiling, but you can insulate under suspended timber floors.
  • Although some experts recommend wall insulation for existing homes, it’s difficult and relatively expensive and usually only occurs during construction or a major renovation. If you’re thinking of building, see Mandatory energy ratings for regulations governing the energy efficiency of new buildings.
  • Next, decide which insulation you’re going to use (see Insulation products, and Table 1). If you decide on loose fill, you’ll need to have the insulation professionally done; if you want to do it yourself you’ll have to choose batts (see DIY for more).
  • Check what R-value is recommended for the area you live in, and that you can get that value in the material you’re thinking of using. Ask about the price per square metre of the insulation you’ve chosen — this can vary, so be prepared to shop around.
  • Check your chosen product is accredited to the Australian and New Zealand Standard 4859.1. Ask the supplier to show you any test certificates or performance guarantees they have for the product, as well as the product’s fire and pest resistance. (The body that tests insulation is called BRANZ — Building Research Australia and New Zealand.)
  • Ensure water can’t get into the roof you’re insulating, as moisture damages some insulation materials’ performance. If it does get very wet, experts recommend you remove it and have new insulation put in.
  • One reader told us her laundry ceiling fell in due to the weight of water from a pipe leaking into the insulation. While uncommon, it does happen with some materials, so check your roof space occasionally for leaks, especially after a storm.
  • Have an electrician check your wiring to make sure it can be safely covered by insulation, or advise how to work around it.
  • Some parts of the building structure (such as ceiling joists or steel frames) may have a lower R-value than the material placed between them, so higher levels of insulation need to be added around those areas. Insulation strips can be inserted between the joist or frame and the roof lining to reduce thermal loss.

Tips for an energy-efficient home

  • Draughtproof Make sure doors and windows are properly sealed — you can buy draught excluders or window seals very cheaply.
  • Seal your chimney with a damper. Avoid installing downlights — besides using a lot of energy, they penetrate the ceiling and insulation, causing heat loss.
  • Shade Keep your home cool in hot weather by shading the windows that directly receive sun (north, east and west-facing windows). External awnings block more heat than internal blinds (because the heat’s already inside by then). You can also plant deciduous trees near the windows.
  • Ventilate Ceiling fans are much cheaper than air conditioning and have less impact environmentally, though they don’t cool the air, only move it about to produce a breeze.
  • If you have air con, try to use it only on really hot or humid days and have it zoned, so you can turn it off in the areas of the house you’re not using.

If you live in a dry area of the country evaporative coolers are effective (although unsuitable during water shortages).

For more information on energy efficiency, go to the Australian Greenhouse Office's 'Your Home' guide.


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