Insulation materials work by slowing down the heat loss from a building, keeping the building warmer for longer. The higher the R rating of a product, the better the product's ability to slow the heat loss, and the warmer you will stay indoors and energy you will save.
Fibreglass is New Zealand's most popular and cost-effective insulation material. The product is easy to cut and available in blankets or precut pieces installed by laying them without gaps in the ceiling or wall cavities.
Fibreglass insulation is made from recycled glass and silica sand. Glass is melted down, extruded into fibres coated with resins, and then bonded into a matt. Most fibreglass insulations use Formaldehyde based resins, although Earthwool formaldehyde-free version is now also available through us. Currently there is an extensive range of formaldehyde insulation available for purchase in New Zealand, ranging from very dusty products with high levels of Formaldehyde in resins that will last for an unknown amount of time to products with very little dust that are not manufactured using Formaldehyde and will maintain their loft over 50 years. For all fibreglass insulation, it is recommended that you wear long sleeve clothing and a dust mask during installation.
There are several brands of fibreglass insulation, but only a few are trusted BRANZ appraised or tested to ensure that the R rating of the claimed product will be achieved and will continue to be maintained by the 50-year minimum durability period as required by the building code. Some products use older style binders similar to that used in New Zealand 20 years ago that are known to have issues with products loft sagging, reducing the R ratings.
Care should be taken to ensure that fibreglass insulation never becomes damp, as the product loft will be destroyed even after the product dries out. If your roof has leaks, these should be repaired before installing your new insulation.
We recommend Polygold Fibreglass insulation which is BRANZ tested, offers exceptional value for money and convenient delivery to many New Zealand towns.
Polyester is made from recycled Coke bottles and is the same material from which duvet inners and many jackets. Products can be ripped in one direction, often installed in blanket form. This product is formaldehyde and dust free, making it an ideal choice for allergy sufferers. Polyester is unique in that it returns to its full loft if it ever becomes damp and is well known for maintaining it for a very long time. Polyester is more expensive than fibreglass.