How much does insulation save on heating?

Ceiling and underfloor insulation can cut heating energy noticeably, often 10% to 30% in a previously uninsulated home, because most heat is lost through the roof and floor. The saving depends on your climate, heating habits and how much insulation you add.

Does insulation pay for itself?

Ceiling and underfloor insulation is one of the cheapest efficiency upgrades, so it often pays back faster than glazing or a new heat pump, while also making the home warmer, drier and healthier.

Is insulation required for rentals?

Yes. Ceiling and underfloor insulation, where practical, has been required in rentals, and the Healthy Homes Standards set minimum requirements. Owner-occupiers are not required to insulate but benefit from doing so.

Insulation Savings Calculator

This New Zealand calculator estimates the heating savings from insulating your home and the payback on the install cost. Ceiling and underfloor insulation is one of the cheapest efficiency upgrades, since most heat escapes through the roof and floor, so it often pays back faster than glazing while making the home warmer and drier. You enter the cost, your heating bill and the saving, and the tool shows the yearly saving and payback.

Insulation install cost

Annual heating cost

Heating saved

payback period

Saving per year$0

Saved over 15 years$0

Ceiling and underfloor insulation give most of the saving for the least cost. Beyond the dollars, a warmer, drier home is healthier and is required for rentals under the Healthy Homes Standards. Estimate only.

How it works

The calculator applies the heating-saving percentage to your annual heating cost for the yearly dollar saving, then divides the install cost by it for the payback. Insulation is usually the best-value efficiency upgrade because it is cheap relative to the heat it retains, so the payback is often just a few years, and the comfort gain is immediate.

Worked example

On a $1,600 heating bill, a 20% saving is $320 a year. A $3,000 install pays back in around 9 years on energy alone, saving about $4,800 over 15 years, plus a warmer, drier home the whole time.

Related calculators

Double Glazing Payback Calculator: glazing payback.
Heat Pump Savings Calculator: heating savings.
Home Heating Cost Calculator: heating costs.
Electricity Cost Calculator: power costs.

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