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Episode 16 :: Check your insulation

If you're having trouble keeping your home warm, it's worth checking whether a lack of insulation is the culprit.


Nearly 60% of our houses don't have good enough ceiling and underfloor insulation, for a number of reasons. It can move around, get old and thin, and become damaged over time. Or, if you're in an older house, there may not have been any insulation put in when it was built.

Here's how to see whether your insulation is doing the job it should:

Signs that your ceiling and underfloor insulation need attention

If it's clear you don't have any insulation at all, the answer's simple - get insulated.

If there is some ceiling and underfloor insulation, here are some signs that it may need some attention:

arrow icon It's damp. Damp insulation is much less effective. Get the source of the dampness repaired, and remove and replace the damp insulation.

arrow icon It's not thick enough. It should be at least 12 cm thick in your ceiling (thicker than your ceiling joists), and at least 9 cm thick under your floor (unless you have foil)..If it's less, get your insulation topped up

arrow icon It doesn't cover the whole area. If there are gaps in your ceiling and underfloor insulation, it won't hold the heat in properly. If your insulation has moved, reposition it - otherwise, get the gaps in your insulation filled.

arrow icon It's on top of (or too close to) down lights. Insulation that doesn't have a 150 mm safety gap around down lights, or other heat sources, is a fire safety hazard - it's really important to get it sorted.

>> Find out more about safe installation of insulation around down lights, chimneys and flues.

For a more comprehensive list visit our webpage about checking your insulation

Fixing, replacing or getting new insulation

If you're putting in new insulation or topping up your old stuff, here are a few things to keep in mind:

arrow icon Good installation is crucial for performance. Poor installation can reduce your insulation's performance by up to 50%. EECA recommends getting it done professionally, but if you want to do it yourself follow the guidelines in the NZS 4246:2006 insulation installation standard.

arrow icon Don't forget your heating. You can create a warmer, healthier home by matching good insulation with an efficient heating system.

Did you know?

arrow icon In the average uninsulated home, around 40% of heat is lost through the ceiling.

More information