Insulation
Insulation is a material usually placed in your home’s ceiling, walls and/or floor to help prevent heat loss and gain in your home. Insulated homes are naturally warmer in winter and cooler in summer, so they’re more comfortable to live in.
Insulating your home can save you $100 a year in heating and cooling costs and up to a tonne of greenhouse gas emissions. Savings will be higher in colder climates. Some types of insulation can also make your house more soundproof. When considering installing insulation, it is important to consider:
the type of insulation
how insulation will be installed
what climate you live in
the cost of insulation and the savings in heating and cooling costs
the insulation’s R-value
staying safe with insulation.
Types of insulation
There are two main types of insulation – bulk insulation and reflective insulation, although sometimes they are combined into a composite. Within these types there are many different products available.
Bulk insulation
Bulk insulation works by reducing the amount of heat transferred through a roof, wall or floor in the same way as a jumper keeps you warm. Like a jumper, bulk insulation is full of holes, or air pockets. These air pockets help trap heat and resist heat loss.
For this reason, it is important that bulk insulation is not compressed. Compressing the insulation reduces the volume of air and therefore reduces the ability of the material to resist heat transfer.
Examples of bulk insulation include batts and loose fill insulation made of materials such as glasswool, wool, cellulose fibre (such as newspaper and straw), polyester and polystyrene.
Reflective insulation
Reflective insulation works by reflecting large amounts of heat away from its polished metallic surface. This surface is usually made out of aluminium foil laminated onto paper or plastic. Reflective foil is often supplied in rolls however other examples include concertina foil batts and multi-cell reflective batts. Together these are known as reflective foil laminates.
Insulation R-Values
When choosing insulation, the most important factor to consider is its R-value. The R-value is a measure of how well the material keeps heat in. The higher the R value, the greater the energy savings. This value matters more than the thickness of the material as some materials are more effective than others at insulating.
Ceiling, roof and floor insulation R-values are shown as an ‘up’ and a ‘down’ R-value. ‘Up’ values refer to the insulation’s ability to keep heat in (for winter) and ‘down’ values refer to the insulation’s ability to keep heat out (for summer). These figures can vary significantly.
The total R-value of a material is how much heat is kept in once the insulation is installed. This is different to the insulation’s R-value as your roof, ceiling or floors add to the insulation effect.
To find the R-value(s) of a material, you can look on the material’s packaging or ask the manufacturer. It’s also a good idea to ask how much of the insulation is recycled. By having recycled insulation you can reduce waste and be kinder to the environment.
What R-value(s) should I use?
The minimum total R-value you should use depends on your climate and what your home is made out of. This is because some climates get colder (or warmer) than others, so more heat needs to be kept in or out. If you are in an area with high humidity and you use natural ventilation, pick high down values and low up values for ceiling insulation.
Please refer to the table below to find the minimum recommended R-values:
Insulation Area | Climate | Minimum total R-value | Minimum insulation R-value |
| Ceiling | General NSW | 4.1 - 5.1 | 3.7 - 4.7 down | 3.7 - 4.9 up |
| | Alpine areas* (e.g. Guyra and Snowy River LGAs) | 6.3 | 5.6 - 5.9 down | 5.9 - 6.1 up |
| Wall | General NSW | 2.8 | 0.4 - 2.4 | |
| | Alpine areas* (e.g. Guyra and Snowy River LGAs) | 3.8 | 1.4 - 3.4 | |
Source: Building Code of Australia 2011 Volume 2 Part 3.12
*Alpine areas are rare in NSW and have cold to very cold winters with some snowfall, warm to hot dry summers, four very distinct seasons and a high daily temperature range.
For more information on R-values, please refer to the Your Home technical manual.
Page last updated: 15 September 2011
