How Much Does It Cost to Insulate a House in Australia? From Hobart to Darwin and Everywhere in Between

The cost to insulate a house can range significantly depending on where you live, the size of your home, what type of insulation you use, labour costs and more. In this article we break down the cost of insulation so you can budget better for your insulation project and make sure the investment is worth it. For project-specific advice and accurate quotes, it’s best to get in touch with suppliers and installers directly. To speak with an expert at Pricewise Insulation today, give us a call on 1300 729 639.

How Much Does It Cost to Insulate a Whole House?

In Australia, a full home insulation estimate ranges between $8,000 and $15,000, which includes insulating the roof, ceiling, walls and underfloor. Prices may vary considerably depending on the size of your home, where you live and the complexity of the job. Keep the following factors in mind when budgeting for insulation in your home:

Size of Your House

The larger your house, the more insulation you will need and the longer the install is likely to take.

New Home vs Existing Home

The most cost-effective time to install insulation is during a new construction or major renovations as this is when the wall, floor and ceiling cavities are most accessible. If you are building a new home or doing some major renovations, it’s highly recommended to install insulation as you may not get the same chance later on. Opening up walls or roofing material can be very costly. For existing homes with safe access to the roof space or underfloor area, it may be possible to install new insulation later, without major renovations. Keep in mind that any damaged or mouldy existing insulation will need to be professionally removed before the new insulation material can be installed. Removing old insulation will be an additional cost.

Labour Costs

Professional insulation companies charge a square metre rate, which varies according to the difficulty of the job and the application. For example, new homes are easier to insulate than existing older homes, and flat ceilings are easier to insulate than raked ceilings. These are the types of factors that determine how much it costs to insulate a home in Australia. Simple installation jobs may take as little as 2 hours, but for a whole home, it could take one to two days of work. Any special equipment needed may drive up the costs and complex installations tend to cost more. For example, if additional ventilation needs to be added or existing insulation needs to be removed. Some people decide to DIY the installation to save on labour costs. It’s important that you do your research and understand how to correctly install your insulation product to make sure you get the best performance. There are some safety risks when handling insulation – check out our DIY insulation videos to understand what’s involved.

Cost to Insulate Different Areas of Your House

To experience the maximum benefits of insulation and save more on your power bill, it’s best to insulate the entire home. Any areas that are left under-insulated are vulnerable to heat loss and gain. If you are on a tight budget, you may consider insulating one area of your home at a time. Below we break down the costs associated with insulating different areas of your home and things to watch out for.

Ceiling vs Roof – Do You Have to Insulate Both?

Insulation in the roof or ceiling is crucial as this is where the greatest amount of heat loss and gain occurs. The type and method of insulating depend on the type of roof you have and whether you can access the ceiling cavity. For many Australian homes, installing ceiling insulation batts between the ceiling joists as well as reflective insulation under the roofing material is the most effective.

Ceiling Insulation

Estimates for ceiling insulation depend on the size of your home and what R-Value you need to achieve. Dive deeper with our guide on how much ceiling insulation costs.

Roof Insulation

For warmer regions like Perth and Brisbane, insulating a 100 m2 roof at R4.0 may set you back around $840-$860. Cooler climates that need to achieve R5.0 are more likely to pay $1.300-$1,400 for a 100m2 roof. Read more: How much it costs to install roof insulation in Australia.

Attic Insulation

If you are planning on using your attic space as a liveable room or storage, you may need extra insulation which will increase costs. Read more: How to work out the cost of adding insulation to your attic.

Underfloor Insulation

Two common insulation materials for underfloor applications include batts and polystyrene. Prices for underfloor batts vary depending on the R-Value and material, but it's worth noting that polyester batts tend to be more expensive than glasswool. XPS and EPS rigid foam insulation products are another option worth considering. Not sure if underfloor insulation is the right move? Check out this article: Is underfloor insulation worth it?

Wall Insulation

External walls are typically insulated using batt insulation, sometimes in combination with reflective wall wrap insulation. Click on the links below to quickly calculate the cost of the wall insulation you need for your next project:

• Wall batts 
• Vapour permeable wall wrap 
• Reflective foil insulation 

For internal walls, acoustic wall batts are recommended to prevent unwanted sound transfer between rooms.

To reduce labour costs, it’s best to insulate existing walls during major renovations when the wall cavity is exposed. Read more: Retrofit wall insulation for existing homes.

Garage Insulation

Garage or shed insulation can help shield against wind, rain and extreme heat. If your garage is located underneath your home or shares a wall with your home, insulation will help prevent heat transfer to protect your home from unwanted temperature fluctuations. A great product for garage and shed applications is Kingspan Insulshed. It costs around $10 per m2.

Double-Storey Homes

For double or multi-storey homes, it’s highly recommended that you have acoustic insulation installed between the different floors to prevent the transfer of unwanted noise. R4.0 or higher is recommended to reduce heat loss and gain between floors. A 100 m2 mid-floor space will cost around $900 – $1,800 to insulate with sound insulation, plus labour costs. Some of our most popular mid-floor insulation products include:

• Bradford SoundScreen Acoustic Insulation Batts $19-$31 per m2
• Knauf Earthwool Acoustic Mid-Floor Insulation Batts $9-$23 per m2
• Pink Soundbreak Insulation Batts $15-$26 per m2

Read more: How to install sound insulation between floors.

How Much Does It Cost to Insulate a House in Australia?

The cost to insulate a house in Australia depends on your location and local climate. Labour costs vary from state to state and you may be subject to local building regulations when it comes to minimum R-Values. Cooler regions typically need a higher rating of insulation to cope with the cold. Regions with hot summers benefit significantly from reflective insulation in the roof.

What R-Value Do You Need?

R-Value measures the insulation's ability to restrict heat transfer. In other words, the higher the R-Value, the better it is at resisting heat flow and the bigger potential savings you can make on your energy bills. For more info, check out our guide: What does R-Value mean?

Products with a higher R-Value cost more than comparable products with lower R-Values. It’s important to weigh up the initial cost vs the lifetime value when deciding on a product. Going with an R-Value that is too low means you won’t get the thermal benefits you were hoping for. However, upgrading to the highest R-Value in a warm climate may not be necessary. Check out the cost guide below based on where you live:

Cost to Insulate a House in Darwin and Northern WA

For the hottest locations across Australia, we recommend R4.0 in the ceiling, R2.0 in the external walls and R2.5 acoustic insulation for internal walls.

• Insulating a 100m2 ceiling with R4.0 batts will cost around $800-$1,600
• Insulating the walls in a 3 bedroom home will cost around $1,500-$3,000

Cost to Insulate a House in Brisbane and Perth

Locations like Brisbane, Perth and northern NSW experience warm summers, heat waves and mild winters. R4.0 or higher is recommended for the roof and ceiling and R2.0 is recommended for external wall applications. Reflective insulation under the roofing material is particularly important for reflecting radiant heat from the sun away from the home during the hotter months.

• Insulating a 100m2 ceiling with R4.0 batts will cost around $800-$1,600
• Insulating the walls in a 3 bedroom home will cost around $1,500-$3,000

Cost to Insulate a House in Melbourne, Adelaide and Sydney

Subtropical oceanic climates, like Melbourne, Adelaide and Sydney, may experience cold winters and mild summers with the occasional heat wave. R5.0 or higher is recommended for ceiling and roof applications and R2.5 or higher is recommended for walls.

• Cost estimates for insulating a 100m2 ceiling range from $1,800 to $2,500 including materials and labour.
• Insulating the walls in a 3 bedroom house may cost $3,000 to $5,000.

Cost to Insulate a House in Alpine Regions

Homes located in alpine regions, such as the Snowy Mountains in NSW and the Bogong High Plains in Victoria, need to cope with temperatures below 0 degrees Celsius. We recommend a minimum of R6.0 or R7.0 for home insulation in alpine regions. It's possible to use multiple layers of insulation to achieve a higher R-Value. Our highest rated (R7.0) batts from Bradford are Bradford Hi-Performance Ceiling Batts, and Knauf Earthwool ceiling insulation is now available in an R8.0.

• Insulating a 100m2 ceiling could cost $2,500 to $4,000.
• Insulating the walls of a 3 bedroom home may cost upwards of $4,000.

Is Insulating Your Home Worth It?

Whether you insulate your entire home or just upgrade your ceiling insulation, it can be a significant financial investment. The good news is that insulation has immediate tangible effects on temperature regulation inside your home and can save you a lot of money in the long run.

Will Adding Insulation Save Me Money?

Although the initial price you pay for home insulation may seem significant, over time it can save you a lot of money. In fact, insulation is the best way to improve energy efficiency in your home and cut down on electricity costs. Keep in mind the higher the R-Value, the more effective the insulation will be at keeping your home cool in summer and warm in winter. If you are building or renovating, now is the best time to insulate or to upgrade your existing insulation.

What Happens if You Don’t Insulate a House?

When a house doesn’t have insulation or is under-insulated, it can’t regulate temperatures effectively. On a hot day, the heat outside will quickly transfer through the building structure and into the house. Conversely, on a cold day, the warmth generated indoors will continuously be lost through the uninsulated ceiling, walls and underfloor. Uncomfortable indoor temperatures aren’t only unpleasant to live in, they also lead to higher use of your heating and cooling appliances which can be very costly. Homes that don’t have any sound insulation between rooms can be uncomfortably noisy as sound travels easily between the uninsulated walls, leading to constant disturbances and making it hard to have a private conversation.

Is It Worth Insulating an Old House?

Insulating an existing home is a smart idea if you are planning major renovations where the wall cavities will be exposed or if you are re-doing the floors. Many older Australian homes have poor insulation that has not been upgraded for many decades. This can cause uncomfortable temperatures inside the home and needlessly high energy bills. If a renovation isn’t on the cards right now, insulating your ceiling could still be possible at an affordable price. New ceiling insulation will help slow down heat flow and improve energy efficiency. Don’t forget to also seal up any unwanted air leaks, as this will also help to boost the overall energy efficiency of the building.

Get an Accurate Home Insulation Quote Today

Pricewise Insulation is Australia’s largest online insulation store. We stock and supply a huge range of high performing, cost-effective products for new and existing homes. Visit our product pages for fast and accurate home insulation estimates. We also offer a professional installation service in Melbourne and Sydney. Contact us today for an obligation-free quote. If you need advice about what products to use or how to insulate your home effectively, call us on 1300 729 639 and our team will be happy to help.