Here are some simple ways to check.
If you can safely access your roof space, check to see if there are any gaps in your insulation. Many people find that there are gaps where insulation has been accidentally moved by tradespeople, accessing your roof space. It’s important to cover these gaps, to ensure the insulation is effective.
It’s also worth checking the thickness of your insulation, as most homes in Australia don’t have enough insulation required for their climatic zone. If your insulation is less than 20cm thick you will benefit from additional ceiling insulation.
If your home was built before the 1990s, it’s likely to have no insulation in the walls at all. An insulation supplier can use a thermal imaging camera to help you see if this is the case in your home.
If you have draughty floorboards, a cold floor and a suitable accessible underfloor space, then you may benefit from installing under floor insulation.