Polyester vs Glasswool

Polyester vs glasswool insulation - blog banner image

An investment for the life of your home

Insulation is an investment in the future comfort and energy efficiency of your home. When deciding on a brand and type of insulation, you need to ask yourself some key questions. We hope this article will help you to make an informed decision.

Most insulation brands sold in Australia are made from glasswool, also known as fibreglass. Glasswool has numerous benefits which make it such an effective insulation material. It’s main ingredient being recycled glass and sand, it can’t catch fire, does not attract vermin, doesn’t rot, and isn’t prone to absorbing airborne moister. It’s fairly easy to cut with a sharp knife, and quite simple to install. The millions of tiny airpockets give glasswool its fantastic insulating properties.

So what are the advantages of polyester then?

In this example we’ll compare glasswool with GreenStuf, which is manufactured from 100% polyester. GreenStuf has practically all the above mentioned benefits, and it also has some additional benefits. It contains no breathable fibres and is certified as being not flammable.

Photo of Autex Greenstuf Polyester Insulation Batts
Polyester insulation is exceptionally soft to handle

This may be significant for asthma sufferers or those suffering from serious dust allergies, and is probably one of the main advantages of polyester insulation. Now how much dust (say in your ceiling space) will actually find it’s way into the living area? That’s a very good question, and the answer is probably ‘not much.’ The most dust you will likely experience invading your home from the ceiling space will be when you attempt to change a ceiling downlight globe. However here it’s important to point out that in an old ceiling, there is likely to be a lot of dust anyway – regardless of whether or not there is insulation in the roof space, and regardless of whether any insulation installed is polyester of glasswool. But it would be fair to assume that if all other factors were equal, polyester would be the least dusty alternative, in particular in a new building.

Huge difference in delivery costs

A key difference worth noting if you’re planning on ordering insulation, is the cost of getting it delivered. Polyester is typically a bulky product when compared to glasswool. If you live in or near one of Australia’s biggest cities, this will probably be of little concern. However once you move away from Sydney, Melbourne, Brisbane or Perth, then delivery can become very costly.

Photo of a man installing glasswool wall insulation
Glasswool insulation is often cheaper than polyester

For example, if you have a 130m2 ceiling, and you plan to insulate it with R3.5 Earthwool ceiling insulation. This will easily fit onto one pallet, whereas you would need around 4 pallets (or pallet spaces) to ship the equivalent R3.5 GreenStuf ceiling insulation. In practice this means you might quickly find yourself needing to factor in an extra 30% – 40% of the materials cost simply to cover the freight costs, especially if you live in a remote area. With glasswool, in most cases the delivery fees will be more be in the order of 10%- 20%. These are not exact figures, but can provide a helpful indication.

Summary and conclusion: glasswool vs polyester batts

  • Polyester insulation is exceptionally soft to handle and has no dusty particles, making it an extra attractive option for allergy sufferers
  • We recommend you use our website shopping cart to calculate the cost of either option, and confirm the delivery cost with us if you live outside Sydney or Melbourne.
  • Then compare the difference in costs, and determine whether the extra cost of the poly insulation option is justifiable.

If you need more advice, don’t hesitate to contact us on 1300 729 639!

Best Sellers

  • Greenstuf® Polyester Ceiling Insulation

    $ 5.58$ 22.68 p/m2 inc. GST
  • Greenstuf® Wall Insulation Batts

    $ 3.92$ 15.59 p/m2 inc. GST
  • Pink Soundbreak Insulation Batts

    $ 8.18$ 15.72 p/m2 inc. GST

2 thoughts on “Polyester vs Glasswool

  1. Melissa says:

    But what about the insulation abilities of the above mentioned batts? Is one better than the other in that regard? Does one out do the other when it comes to staying in place and not sagging? How do they hold up overtime? Is a roll of insulation better than individual batts?
    A bit more info is needed to really compare one form of insulation against another.

    • Pricewise Insulation says:

      Hi Melissa,

      The performance of the insulation really depends on the R-value. An R2.0 Greenstuf Polyester Batt and an R2.0 Pink Batt will provide the same thermal performance. Our professional installers use glasswool batts in the walls and ceilings and polyester rolls in the underfloors of new homes. That being said, we do not recommend buying low quality fibreglass batts produced in Asia. Stick to well known brands such as Earthwool, Bradford, Pink Batts and Greenstuf.

      R2.0HD Knauf Earthwool Acoustic Batts are more rigid than normal R2.0 thermal batts and therefore less likely to sag in the walls. However, R1.5 and R2.0 thermal wall batts also work well when installed correctly.

      If you need to cut your batts to fit the wall joists, make sure you cut them a little wider than the spacing between the joists. They shouldn’t be so wide that the edges fold in but they should fit in snugly. You can find some useful information on our DIY video page.

      If you have any more questions please don’t hesitate to contact us on 1300 729 639.

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