Do you have ceiling insulation? Is it up to scratch? Use a stepladder to access your roof space via the ceiling hatch. Or get an insulation professional to do it for you – they often do it for free.
Need to sort it out?
See if you can get a grant
Warmer Kiwi Homes is a Government programme offering insulation and heating grants to low-income home owners.
Call the professionals
Get quotes from at least two trained installation installers. We recommend choosing an Insulation Association of New Zealand (IAONZ) member.
Install it yourself
Everything you need to know is in the New Zealand Standard. It’s easy to follow – but there’s a lot to know if you want to do a good job. Take care to follow the health and safety advice in Appendix B.
You’ve got insulation – what next?
Check coverageYou’ll need a top-up layer if it’s less than 12cm thick, doesn't cover the whole ceiling, has gaps in it or places where it’s squashed or tucked in.
Check for damageRemove old insulation and start again with a new layer if it’s wet or damp in places, or it’s been damaged by rodents or birds. Fix holes in the roof for future protection.
Check for safety
There should be gaps between insulation and heat sources like older recessed downlights, chimneys, flues or extractor fans for fire safety. See Appendix A of the New Zealand Standard for details and pictures.
Types of ceiling insulation
Comes in a roll and can cover ceiling joists so heat doesn’t escape through the timber. An easy option to top up existing insulation because you can just roll it over what’s there already.
Big pieces of insulation that fit between ceiling joists and can be cut to size. This leaves the joist exposed – handy for moving through the ceiling space but means heat can be lost through the timber. Use a denser product to make up for it.
Insulation blown onto the can be a good option if access is difficult – but its safety and effectiveness depends on the quality of the material used as well as the installer's equipment and experience.
How much is enough?
The R-value is a measurement of insulation effectiveness - the higher the R-value, the better it prevents heat loss. There are minimum requirements for rental homes, new homes and alterations. Use them as a guide for retrofitting ceiling insulation into an existing home – but in all cases, go much higher if you can.
Roofs with no ceiling space
Insulating a home with a skillion or flat roof, or a cathedral ceiling, is best done when reroofing or renovating. There are solutions but it’s a skilled job – getting it wrong can cause moisture problems. Ask a qualified builder or roofer for advice.
Some modern LED downlights can have insulation fitted over them, instead of having to leave a gap for fire prevention. Not only does this stop your warmth escaping – the super-efficient LEDs use less energy and can save lighting costs. Ask a lighting specialist or registered electrician for advice.
Need some healthy home advice?
Get guidance to assess how warm, safe and dry your home is, and discover what you can do to improve it. You can do a healthy home check yourself online, or a certified advisor can visit and assess your home, and tailor an improvement plan. Many offer their services free of charge.