What should I insulate? – AEF | Australian Energy Foundation

What should I insulate?

You can insulate your home’s ceiling, walls and underfloor space.


Ceilings are insulated with bulk insulation in the form of batts or ‘blankets’ made from polyester, sheep’s wool or fibreglass wool. Some bulk insulation also comes with reflective foil attached to one side, which reflects the sun’s heat in summer, keeping your home cool.

Some homes don’t have an accessible roof space. For instance, if you have cathedral ceilings, board insulation, such as polystyrene boards can be a good option.

Wall Cavities

Your home’s walls can be insulated in two main ways. 

If you’re building new walls, or have a weatherboard home that needs to have some weatherboards replaced, you can insulate the walls by placing batts directly into the wall cavity. 

If you’re not renovating, blow-in wall insulation is an alternative way to insulate your walls. Blow-in insulation involves drilling holes about the size of a 50 cent coin into the mortar between the bricks. A loose-fill insulation, such as rockwool, is then pumped into the wall. The hole is then filled with matching mortar, ensuring that they’re concealed.


Polyester batts or polysterene boards are used to insulate under your home’s floor. This is usually only possible if you have adequate crawl space under your house. 

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