Wall Insulation Cost Calculator
Estimate the cost of insulating existing walls. Enter the wall area, retrofitting insulation into finished walls is done by blowing it in through small holes, and the access, not the material, is the cost.
Your wall insulation details
Your estimate sits within the typical range.
Walls are the second-biggest source of heat gain and loss after the roof, but retrofitting them is expensive. If you are not renovating, blow-in is the cost-effective way to insulate existing walls.
💰 Ways to save
- Insulate walls while renovating or re-cladding, doing it when the walls are open is a fraction of the retrofit cost.
- Blow-in is the cheapest retrofit for finished walls, no cladding removal.
- Prioritise the roof first, walls second, the roof gives more comfort per dollar.
or from $18/week over 5 years , indicative finance
How we estimate this
Insulating existing walls in Australia typically costs around $30 to $60 per square metre of wall in 2026 for blow-in retrofit, so a typical home often lands around $2,500 to $6,000. Removing cladding to fit batts costs more, doing it during a renovation costs far less.
Pricing reviewed: November 2026.
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Pricing reviewed November 2026. Indicative Australian costs, not a quote.
Understanding wall insulation costs in Australia
Insulating existing walls in Australia typically costs around $30 to $60 per square metre of wall in 2026 for blow-in retrofit, so a typical home often lands around $2,500 to $6,000. Removing cladding to fit batts costs more, doing it during a renovation costs far less.
The material is cheap, the access is not. In a finished home, insulation is blown in through small drilled holes. The cheapest time to insulate walls is during a renovation or re-clad, when the cavity is already open.
Frequently asked questions
How much does wall insulation cost in Australia?
Roughly $30 to $60 per square metre of wall for blow-in retrofit in 2026, so about $2,500 to $6,000 for a typical home. Removing cladding costs more, insulating during a renovation costs much less.
Can you insulate existing walls without removing them?
Yes, with blow-in insulation injected through small holes that are then patched. It is the cost-effective retrofit method, far cheaper than removing and replacing the cladding.
Are you a insulation installer?
Everyone on this page is working out what wall insulation costs because they are ready to hire. Put your business right beneath the calculator, in your state, so you are who they find. From $50/mo.