Polyester vs Glasswool


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.

What is insulation made of?

Glasswool insulation most common

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. Because its main ingredient is recycled glass and sand, it can’t catch fire, does not attract vermin, doesn’t rot, and isn’t prone to absorbing airborne moisture. It is 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 about polyester insulation then?

Autex GreenStuf manufactures insulation made wholly from polyester. Polyester insulation has practically all the above mentioned benefits, and it also has some additional benefits. It contains no breathable fibres. This may be significant for asthma sufferers or those suffering from serious dust allergies. 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, particularly in a new building.

How much does it cost to insulate a house with polyester insulation?

In this example we’ll compare glasswool with Autex GreenStuf, which is manufactured from 100% polyester. Many people who installed insulation back in the day will have memories of working with near unbearable products and for them polyester insulation is the only option, even though it is a lot more expensive. They argue that no price is to high to work with a product that is completely itch free. In fact, you can almost sleep in the stuff! No amount of convincing about technological advances in glasswool production will get them to change their mind. To them it’s GreenStuf or no stuff!

Huge difference in delivery costs

The key difference worth noting if you’re planning to order 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 New Zealand’s major cities, this will probably be of little concern. However once you move away from the larger centres such as Auckland, Wellington, Christchurch, Hamilton and Tauranga then delivery can start becoming costly. For example, if you have a 130m2 ceiling, and you plan to insulate it with R3.6 Earthwool Glasswool Ceiling Insulation. This will easily fit onto one pallet, whereas you would need around 4 pallets (or pallet spaces) to ship the equivalent R3.4 GreenStuf Polyester 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 segments

  • Polyester is exceptionally soft to handle and has no dusty particles, making it a particularly attractive option for allergy sufferers
  • We recommend you use our website shopping cart to calculate the cost of both options, and confirm the delivery cost with us if you live outside the major cities.
  • Then compare the difference, and determine whether the extra cost of the polyester option is justifiable.

If you need more advice, don’t hesitate to contact us.

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