Home Insulation

Insulation has a huge impact on the comfort on your home, helping to keep it warm in winter and cool in the summer. The Building Code has minimum requirements. Our strong recommendation is to exceed these by as much as is practicable, given that the more insulation you use, the more efﬁcient your heating will be and the lower the cost of heating.

There are plenty of products and brands to choose from. It’s important to realise that the one you use doesn’t have to be pink.

Insulation product options include:

Wool insulation – natural sheep’s wool (either new or recycled), and may be blended with preservatives and polyester or resin to prevent slumping and to make it pest, mould and ﬁre resistant. Regulations stipulate it must be no less than 95% wool.
Polystyrene can be used under floors or in walls (and is often ‘sandwiched’ within concrete, partly to economise on concrete usage).
Artiﬁcial wool is usually made from specially treated polyester. It is naturally resistant to ﬁre, moisture, vermin, insects, mould and bacteria, eliminating the need for any chemical additives. It is also environmentally friendly, as it is non-toxic, non-irritating and non-allergenic. A high percentage of the polyester ﬁbre in polyester insulation products is made from recycled PET plastic, including plastic bottles and bags, and it is itself fully recyclable at the end of its life and it can be recycled.
Glass-based insulation is usually made from recycled glass and can itself be recycled. Repeated wetting will reduce efﬁcacy. No chemical treatment is necessary as it is naturally resistant to vermin, insects and mould. Care should be taken with installation to avoid breathing glass ﬁbres and it is prone to slumping over time.
SIPs – Structural Insulated Panels – these are walls that are constructed from two hard outer panels with a foam core. They are used instead of standard timber framing, are very quick to erect and offer excellent insulating qualities. Find out more here…

Rating Insulation

The efﬁciency of insulation is rated in ‘R’s: the higher the R-value, the higher the degree of heat retention.

Under the New Zealand Building Code, rooms in new houses must meet R-ratings for the whole room, calculated according to things like window size and what insulation products are used. These requirements are to increase energy efficiency in homes to use less power, leading to a reduction in climate change power generation and lessening the need for additional power generation.

Paying a small amount here to increase the R-rating in your house can make a dramatic difference to your comfort levels (for your wallet, as well) in the long run.

Cross section of a PVC window profile beside a pvc window frame over a plastic surface – thermal insulation and environment protection concept

New homes in different regions of the country now are required to meet minimum insulation measures as an overall measure of the individual room and house, including glazing, so if you have lots of insulation and small windows, you may not necessarily need to install double glazing (though our recommendation is that you do so). Double or triple-glazed windows, aluminium frames with thermal breaks, or timber or u-pvc frames are better at limiting heat loss but not as good as solid walls with insulation, so the more window space in a room, the more insulation is needed in the wall and/or the triple glazing/thermal break options utilised.

Your designer will work through this critical design element with you.
Be aware that gaps in installation can substantially reduce efﬁciency, so it’s important to install it correctly in the first place and to ensure proper upkeep.

Apart from the type of insulation product, you can also have it installed in different ways:

Blanket rolls for roof cavity -easy to install and easier to ensure no gaps, though the edges around the roof cavity can be missed.

Batts – can be used in the roof and walls. Cut to fit in between joists and posts, rely on the insulation quality of timber framing.

Blown – Lesser used and once known as insulfluff – blown insulation can sometimes be found in older ceilings but is generally used for retro-fitting into older home’s wall cavities.