Insulation acts as a barrier to heat loss and heat gain, particularly in roofs and ceilings, walls and floors.
In many homes insulation is the most practical and cost effective way to make a house more energy efficient, keeping it cooler in summer and warmer in winter and saving up to 40 per cent in heating and cooling bills. In addition, insulation may reduce condensation in the home. This can provide health benefits by reducing mould and damp.
Why is insulation important?
Half of the energy we use to heat or cool our homes can simply leak out without insulation.
Insulation helps to:
- reduce reliance on heating and cooling systems
- save money on your energy bills
- improve your comfort at home
- protect the environment and reduce greenhouse gas emissions by lowering your energy consumption.
Some types of insulation can make your home more soundproof.
Insulation should be installed in accordance with the relevant Australian standards and the Building Code of Australia, including ensuring that the insulation meets the minimum requirements for R-Values (ability to prevent heat leaking in our out) and that appropriate clearances are met around electrical wires and appliances.
Installers should comply with the relevant state and territory laws when installing insulation. In some states, such as South Australia, builders are required to be licensed to install insulation.
Seek advice from your state or territory government or building bodies before undertaking any work yourself and before selecting an insulation installer.
Types of insulation
There is a range of insulation products available in Australia. When deciding what type of insulation is appropriate for your home you should seek assistance from an appropriately qualified insulation installer or builder.
There are two main types of insulation:
- Bulk insulation acts as a barrier to heat flow between your home and the outside, keeping heat out of your home in summer and in your home in winter. It comes in batts, rolls, boards and can be made from materials like glass wool, polyester, natural wool or recycled paper. Bulk insulation is usually used in homes located in cooler climates.
- Reflective insulation is generally used to keep your home cool in summer by deflecting radiant heat. It's usually shiny aluminium foil laminated onto paper or plastic. Reflective insulation is usually used in homes located in hot and very sunny climates.
Some insulation products combine features of both bulk and reflective insulation.
What type of insulation is best for you will depend on the climate where you live and whether you need to keep heat in, or out, or both. Your home's design, the material it's made from and its orientation to north are also factors.
Insulation's ability to resist heat flow (prevent heat leaking in or out) is described as its 'R-value'. Insulation products with the same R-value will provide the same level of insulation if installed correctly.
- Incorrect installation, such as compressing or damaging insulation, or leaving gaps between sheets or batts, can result in a product not achieving its specified R-value.
- The level of insulation needed will depend on your home and climate zone.
- The Your Home website has information about recommended insulation levels for your climate.
When to insulate
The best time to install insulation is when you are building or renovating your home. Insulation should be combined with good design—including passive heating and cooling so it can do its job properly keeping you comfortable all year round.
Many states and territories have minimum energy efficiency standards for new residential buildings and building extensions. Insulating your new home is one way to meet these minimum requirements.
Retrofitting insulation is also possible. If you're going to insulate your home at a later stage, the effectiveness and cost will depend on how easy it is to install. For example, it may be more difficult to install insulation in less accessible areas such as existing walls.
What to insulate
Ceiling insulation is particularly important as the highest proportion of heat transfer occurs through the roof and ceiling, but there are other areas of your home that can be insulated as well. To maximise the efficiency of your insulation, draught-proof your home to reduce heated or cooled air leaking from cracks and gaps around windows and doors.
Roofs and ceilings
If your roof or ceiling isn't insulated, you could lose up to 45 percent of your heating and cooling energy via the roof. Verandah roofs should be insulated in hot climates to reduce heat from the sun, as this not only affects the space below, but also the temperature inside the house. Covered verandahs and garages might benefit from insulation if you spend a lot of time in these areas, especially if you are heating or cooling them.
Wall insulation can save up to an additional 20 per cent of heating and cooling energy. Consider added wall insulation as an essential in all climates. Exceptions to this would be homes constructed from straw bale (and to a lesser extent autoclaved aerated concrete—AAC). If wall insulation is not already fitted, or if your existing insulation is insufficient, it can be retrofitted. Speak to your installer about the correct product for your particular home and location.
Appropriate floor insulation can save up to 5 per cent of your winter energy costs. Carpets are one option to insulate a floor. In hot climates floor insulation may interfere with the natural cooling from the ground beneath the house. Seek advice about the best option for your home and circumstance.
Water pipes inside walls can be insulated when building or renovating. To avoid further heat being lost from a storage hot water system, insulating externally exposed pipes leading from the water heater to the house as well as the water tank itself is recommended.
Safety with insulation
It's important that insulation is installed correctly to meet Australian Standards. Although some types can be sold as DIY, it is safer to have insulation installed by a reputable experienced installer—see our helpful links for more information in your state. In South Australia installers must be licensed. Installing insulation carries potential health and safety risks and may require expert knowledge and assistance. Some types of insulation require the use of specialised equipment, masks and protective clothing.
Electrical and fire safety are particularly important considerations. Your installer should:
- Ensure that thermal insulation in roof spaces is clear of electrical fittings.
- Follow Australian New Zealand Standard AS/NZS 3000:2007 Electrical Wiring Rules which provide
sguidance on the separation of electrical equipment and insulation materials. Electricians and insulation installers working in the roof space of your house must follow these guidelines.
- Ensure that you have covers installed on any downlights, to minimise any risk of the downlights coming into contact with your insulation