Insulation Buying Guide
What to look for when buying and installing insulation.
R-value
The performance of insulation is measured by its "R-value". The higher the R-value, the more effective the product.
Just think: "Bigger number = better product".
Recommended R-value's differ across Australia depending on climate, with highest being four and lowest being one. The recommended R-value of a ceiling is usually double that of the walls. The thickness of the insulation has no impact on its R-value - a thinner insulation can have a higher R-value than a thicker one, because it is a better-performing type of insulation..
Cost
The cost of insulation can vary greatly. The higher the R-value the higher the initial cost - but you'll save on energy bills down the track. The Australian Government tells us that good insulation can reduce your energy bills by as much as 40%.
Just think: "Bigger number = Bigger cost + Bigger savings long-term".
Climate / location
Where you live will determine what type of insulation you choose. The Building Code of Australia has set out minimum insulation requirements for eight climate zones within Australia. For example homes in Western Sydney require roof insulation with a minimum R-value of 3.2 in winter. Those in Cairns need only an R-value of 2.2 in summer. Your insulation supplier will be able to tell you which zone you live in.
Safety
Ensure your product comes with flammability test certificates. And, some insulation types such as rockwool and fibreglass can cause irritation to skin, eyes and nose so protective clothing must be worn during installation. See more about the different insulation types and their flammability and irritation levels on our "types of insulation" page.
Categories of insulation
There are two main categories of insulation; some people use a combination of both.
Bulk insulation
Bulk insulation works as a physical barrier to the flow of heat. Types include cellulose fibre, sheep wool, polyester, glasswool and rockwool. You can read more about these on our "types of insulation" page.
Pros:
- Very effective in cooler climates
- Can double well as acoustic insulation
Cons:
- Will lose its effectiveness when damp
- Irritation to skin, nose and eyes can occur when installing some types
Reflective insulation
As the name suggests, reflective insulation works by reflecting heat away with its polished metallic surface. Types include aluminium foil sarking, foil boards, E-therm and foil batts. You can read more about these on our "types of insulation" page.
Pros:
- Very effective in warmer climates
- Acts as barrier to moisture
- Takes up less room than bulk insulation
Cons:
- Needs to be combined with bulk insulation to be effective during winter in cooler climates
- Dust can settle on its surface, reducing effectiveness