Your Complete Guide To Home Insulation

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Professionally installed insulation does more than keep your family cosy in winter and cool in summer. It also cuts heating & cooling bills by 30-40% – but it’s essential to be a well-informed consumer before making a decision

Find out how to check whether your home needs more insulation, and (if so) how to choose the perfect type and installer for your home – with our Complete Guide to Home Insulation. 

Read the guide below or download a pdf to save it for later. 

If you have any more questions or would like help finding a trusted insulation installer, simply complete this short formgive our friendly energy advisors a call at 1300 23 68 55 or email at advice@aef.com.au. We look forward to helping you! 

insulation guide

1. Home Insulation: Why Should I Care?

Australia: a land scorched by heat, sunshine, and desert.

This sizzling image has embedded itself so deeply into global culture that many don’t realize that it’s not quite true.

To be fair, we do have burning summers. And our winters are indeed milder than American and European winters.

But indoors – where we spend 90% of our lives – we actually feel the winter cold more than Americans and Europeans. (Not to mention the blistering summer heat.)

How did we end up literally paying for harsher indoor seasons?

And, more importantly, how can we stop paying for them while enjoying more comfortable homes?

The answer to the first question: Australia’s epidemic of inadequate (or nonexistent) home insulation.

The answer to the second: improved home insulation.

While this practice is almost universal in America and Europe, Australian homeowners are often surprised to learn that a well-insulated home is the key to lower electricity bills – or that their home is poorly insulated in the first place.

Some are even scared off of the entire industry by the poorly implemented Home Insulation program a decade ago.

So they accept more extreme indoor temperatures and higher electricity bills.

Fortunately, improving your home’s insulation is simpler and more affordable than most people think. In fact, the typical home recoups the insulation costs within 5-6 years, in the form of 40-50% lower heating and cooling bills. 

But the home insulation scheme did prove one thing: you have to be a well-informed consumer to be able to choose an experienced and qualified installer.

So it’s essential to know

  • The basics of insulation
  • How to find a reliable, trustworthy installer
  • The right questions to ask your installer

That’s why we created this complete resource for Australian homeowners.

This clear, reader-friendly guide provides everything you need to know about how to easily and affordably improve

  • your home’s heating and cooling efficiency
  • your family’s year-round comfort
  • your (lower) electricity bills

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2. What’s Home Insulation?

Left to themselves, houses don’t trap much heat or cold inside them.

In fact, much heat can easily escape through your walls, ceilings, and windows in winter – or, conversely, enter your home in summer:

Summer heat gains winter heat loss

Insulation prevents this by slowing down heat loss in winter and heat gains in summer in one (or both) of two ways:

Bulk Insulation (thick layers of dense materials that trap air inside your home)

Foil Insulation (reflective layers that bounce heat back to its source) 

Bulk insulationFoil insulation

Both methods slow down your home’s transfer of heat so that you don’t have to use heaters or air conditioners as much (and when you do, you don’t need to run them as long) to maintain a comfortable indoor temperature. In this way, insulation acts as a blanket for your home.

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3. Is Insulating My Home Worth It?


Compared to the same home without insulation, a properly insulated home results in:

*Statistics from Insulation Council of Australia and New Zealand: 6PP DL LRP

Wait, improved respiratory health? Yes – along with fewer doctor’s visits and fewer missed days at work and school, according to the University of Otago Wellington School of Medicine’s study of nearly 1,400 homes and 5,000 residents.

Since insulation is warrantied for 50-70 years, improving your home’s insulation is a one-time cost that provides financial, environmental, and health benefits for the lifetime of your home.

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4. Do I Already Have Enough Home Insulation?

If your home’s current insulation works for your family, there’s no point in getting more.

However, there’s an 80% chance that this isn’t the case. Unfortunately, effective insulation is very unlikely in Australian homes.

To determine if your home needs more insulation, ask these questions:

  • Was My Home Built Before 2000?

80-90% of homes built before 2000 have no wall insulation, which means that 15-25% of your conditioned air is escaping via your walls.

  • Was My Home Insulated Before 2010?

Since insulation efficiency and awareness has improved significantly since 2010, your pre-2010 home probably has less insulation than that currently recommended.

  • Has My Insulation Been Recently & Thoroughly Checked?

Even if you think your home’s insulation is fine, it’s still worth checking. Just a tiny 5% gap in your ceiling’s insulation can reduce its effectiveness by 50% – and many older houses have 5-10% insulation gaps.

Since insulation settles over time and is often displaced by home contractors such as electricians, you may not be aware of such gaps until you either check your home’s insulation yourself or have a qualified professional do so for you.

While it’s much more convenient to have an insulation professional examine your house’s insulation (click here to arrange an insulation quote), you can do so yourself as well.

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5. How To Check Your Home’s Insulation


Get a ruler and look through the manhole of your ceiling. Even if your insulation looks tidy, look carefully for small gaps and disturbed insulation, especially around downlights.

Signs that you need more ceiling insulation include:

  • Gaps in insulation
  • Insulation not pushed right out to the top plates of the external walls
  • Insulation not lofted above ceiling joists by 50mm or more
Well-insulated Ceiling Insulation
Example of well-insulated ceiling


You can check wall insulation in several ways:

  • Remove roof tiles over the external wall cavity and look inside the cavity
  • Climb under a brick veneer house (if not on a concrete slab) and look up the cavity
  • Have your electrician remove a power point or light switch on 1-2 outer walls so you can see inside the cavity.
  • Have an insulation professional use a thermal imaging camera

If your house is pre-2000, be prepared for the likelihood that it has no wall insulation at all.


Put your head under the floor through the manhole entrance and look for insulation.

If your head can’t fit under the house, you can’t insulate it anyway, so no worries!

Though the above guidelines can help you check if your home has enough insulation, it is always safer to have an experienced qualified expert check your insulation, particularly when entering the ceiling cavity. Our vetted installer can help.

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6. How Much Insulation Does My Home Need?

Find this out by discovering which climate zone you live in:

In each climate zone, the Building Code of Australia has determined a minimum amount of needed insulation expressed in R-value (the efficiency of a material at stopping heat flow through it.)

This is the Building Code’s recommended amount of insulation, in R-values, for each climate zone and insulation type:

Climate Zone









Ceiling insulation for homes with very light coloured roofs









Ceiling insulation for homes with light coloured roofs









Ceiling insulation for homes with dark coloured roofs









Wall insulation









Underfloor insulation









R4.1 is about 20 cm thick.

When checking the R-value of a certain insulate type, find its effective or installed R-value. Due to various building and external conditions, this may differ from its labelled R-value.

For the sake of your budget, remember that more insulation isn’t always better. While more insulation than recommended will indeed improve your home’s heat efficiency, the law of diminishing returns means that it’s not always worth the extra cost.

For this reason, discuss your insulation requirements and budget with a trustworthy installer

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7. Where Does My Home Need Insulation Most? 

winter heat loss

Ceiling Insulation

Since 25-35% of your home’s heat escapes through an uninsulated ceiling, ceiling insulation is essential to keep your home comfortable and your energy bills low.

Most ceilings can be insulated with layers (“batts”) of dense material such as polyester, sheep’s wool, and fibreglass wool (with or without reflective foil to reflect the sun’s heat.)

If your home has no easily accessible attic space (i.e. cathedral ceilings), you can still insulate it with polystyrene boards.

Wall Insulation

15-25% of your costly conditioned air seeps out of your home via uninsulated (or poorly insulated) walls.

Fortunately, all wall types with cavities can be insulated, even double brick walls.

Some homeowners only insulate the hot western walls, which alone cools homes much more efficiently in summer.

However, if you want to save on energy bills in winter as well, insulate all of your exterior walls.

It doesn’t hurt to insulate internal walls too — for example, those between bathrooms, bedrooms, and living rooms. This additional soundproofing will create a more peaceful environment for your family.

How to Insulate Walls 

  1. New Walls and/or Renovations: Place batts directly into wall cavity
  2. No Renovations: Blow-In Insulation 

Installing blow-in insulation means that your insulator will:

  • Drill coin-sized holes into the mortar between the brick
  • Pump a loose-fill insulation, such as rockwool, into the wall
  • Conceal each hole by filling it with matching mortar
Blow-in Wall Insulation
Example of blow-in wall insulation

Floor Insulation

Some homes don’t have enough space under their floors for insulation. In that case, don’t worry about it.

However, if your home does have underfloor insulation space, insulation will:

  • Reduce noise between floors (especially in multi-story homes)
  • Reduce draughts (especially if your home has old, bare floorboards)
  • Prevent an additional 10-20% heat loss

Floors are usually insulated with polyester batts or polysterene boards. 

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8. Can I Add To My Home’s Existing Insulation?

Certainly! No need to throw out effective insulation in good condition.

Even if your insulation has some holes or is compressed, you can usually still add another layer of insulation on top.

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9. Can I D.I.Y. Home Insulation?

It’s tempting to save on installation costs by doing it yourself, but in most cases the electricity dangers far outweigh the possible savings:

  • Downlights and other electric implements pose multiple hazards

To prevent future overheating and house fires, insulation must be installed with a certain amount of space around halogen downlight fittings. This requires the expertise of a professional.

  • Insulation often must be stapled near electric cables

Even a tiny slip of the staple can accidentally penetrate the cable, which can result in injury or death by electrocution. Thus, stapling needs to be done with extreme caution by professionals.

Sadly, the Home Insulation Scheme of 2010 proved the importance of safe, professional insulation installation. This well-meant program ended after four young and inexperienced tradesmen were allowed – against both government and industry policy – to work on insulation installations, and died as a result of not following proper safety procedures.

Fortunately, such tragedies are extremely rare. This is because most insulation installations are done by experienced, well-qualified industry professionals; it’s essential to employ their expert services rather than risk doing it yourself.

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10. Which Insulation Material Is Best For My House?

Typical materials for each area include:



Polyester, Natural Wool, Glass Wool, Expandable or Extruded Polystyrene Batts


Rockwool or blown-in cellulose fibre


Polyester, Expandable or Extruded Polystyrene Batts

When looking for the right material, consider the following:

Environmental Impact

If you’re concerned about your insulation’s environmental impact, look for materials that are made from recycled materials such as glass wool (often made from recycled glass) and polyester products (often made from recycled plastic bottles).

These insulation types help to reduce the amount of virgin material used, which means less energy is used to make them. They also reduce the amount of waste going to landfill.

You can also find some insulation materials made from natural materials such as sheep’s wool.


Fire Safety

Good news: all insulation products sold in Australia conform to Australian Fire Safety Standards, which mean that none of them are able to sustain combustion.

However, some materials are particularly fireproof: rock wool, polyester and glass wool do not combust and, even if exposed to flames, will produce very little smoke or fumes.


Sound Proof

One perk of insulation is its soundproofing capability. If you’re looking for a quieter home, the best soundproofing insulative materials are glass wool, rock wool, and extruded or expandable polystyrene.

Interested in learning more about insulative materials? Check out this in-depth introduction.

In the end, a trustworthy installer will provide the most accurate information on which insulation material will work best for your individual home and family. Simply complete this short form to get an obligation-free quote from our vetted supplier.

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11. How Much Does Home Insulation Cost?

While the exact cost of retrofit insulation depends on the size and construction of your home (in addition to the insulation material used) these are average retrofit insulation estimates for a typical Australian 120 sq. meter home:

Ceiling insulation: $1600 to $4000

Wall insulation: $2850 to $7000

Floor insulation: $2900 to $3500

Fortunately, the least expensive of these is also the most important: ceiling insulation, which alone will prevent up to 35% of heat loss. So even if you don’t currently have the budget for a full home installation, you can still benefit significantly from ceiling-only insulation.

It’s also important to remember that since all three types of insulation lower heating and cooling bills by up to 40-50%, on average they pay for themselves within 5-6 years of installation. 

Looking for an exact estimate of your home’s insulation cost? Contact a vetted, experienced Australian installer for an obligation-free quote.

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12. How Do I Choose A Good Home Insulation Installer?

As seen in Q.9 (and as the defunct Home Insulation Program showed), safe and secure insulation installation requires the expertise of trustworthy, well-qualified, and highly experienced professionals. Follow this checklist to ensure that you find the right insulation installer for your home:

  • Informative, Transparent Sales Process
  • No Pressure Tactics — You should never feel rushed towards a decision
  • Clear, Easily Understood Quote that details all expenses
  • Quick, Attentive, and Courteous Communication (Both on phone and in person)
  • Timeliness in keeping appointments
  • Clear Warranty Information
  • Numerous Positive Online Reviews
  • High-Quality Insulation Materials – Ask them what products and brands they offer, and why. Established businesses will give you evidence-based reasons for offering specific insulation products.

One simple way to ensure a reliable, high-quality insulation installer is to use one already fully vetted. Get in touch for a free, no-pressure home quote from our carefully selected and highly-reviewed insulation partner.

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13. Ready for the next step?

While this guide answered the big 12 questions about home insulation, we know that you’ll probably think of many more as you consider this decision.

Our non-profit team of experienced energy advisors is here to answer any questions you have: just get in touch with us at 1300 23 68 55 or via email for friendly, unbiased professional guidance.

If you’re ready to get a free, no-pressure quote from a fully vetted insulation installer, click here.

And finally, thank you for reading our Complete Guide to Home Insulation! We hope you found it helpful in your journey towards a comfortable home with lower electricity bills.

Download your free copy of the Complete Guide to Home Insulation

insulation guide

The Complete Guide to Home Insulation

Download our brand-new guide to find out all the things you need to know about insulating your home.