Polyester vs Glasswool

Polyester vs Glasswool Insulation - New Zealand

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 New Zealand 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 air pockets 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 by Autex 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.

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 its way into the living area? That’s a very good question, and the answer is probably ‘not much.’ The most dust you are likely to 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 or glasswool. But it would be fair to assume that if all other factors were equal, polyester would be the least dusty alternative, particularly in a new building.

Which is better? Glasswool insulation or polyester?

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 bulkier product when compared to glasswool. If you live in or near one of New Zealand’s biggest cities, this will probably be of little concern. However, once you move away from Auckland, Wellington, Christchurch or Hamilton, then delivery can become very costly.

For example, 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 Autex GreenStuf ceiling insulation. In practice this means you might quickly find yourself needing to factor in an extra 30% – 40% of the material’s 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 Insulation

  • Polyester insulation from Autex 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 Auckland or Wellington
  • 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 0800 697 742!


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