Home / Energy Retrofit Payback Calculator
Energy Retrofit Payback Calculator
Work out how many years an insulation upgrade, draft-proofing job or efficient appliance takes to pay for itself.
Simple payback vs. escalation-adjusted savings
Simple payback period is just the upfront cost divided by the first year's savings — a quick, easy-to-explain number. But energy prices tend to rise over time, so this calculator also projects total savings over a chosen number of years assuming an annual energy price escalation rate, which usually shows a more favourable — and more realistic — long-run picture.
What counts as a retrofit here
This tool is generic to any energy-saving home or building upgrade with an upfront cost and an ongoing annual saving — attic or wall insulation, draft-proofing and air sealing, an efficient heat pump or boiler, or upgraded appliances. It deliberately excludes solar panel installations, which have their own dedicated payback calculators elsewhere on Toolbench.
Frequently asked questions
What is "simple payback period"?
It's the upfront retrofit cost divided by the annual energy cost saving, giving the number of years before the savings equal what you spent — assuming savings stay flat and ignoring the time value of money. It's a quick screening number, not a full financial return calculation.
Why include an energy price escalation rate?
Energy prices have historically tended to rise over time, so a retrofit's savings usually grow year over year rather than staying flat. Including a modest annual escalation rate gives a more realistic — usually shorter — effective payback and a larger total savings figure over the years you project.
What escalation rate should I use if I'm not sure?
A conservative estimate of 2–4% per year is a reasonable default for many regions' historical residential energy price trends, but local utility and fuel price trends vary — check your own region's recent energy price history if you want a more tailored figure, or simply set it to 0% for the most conservative, flat-savings estimate.
Does this include financing costs or tax incentives?
No — this compares upfront cost against savings only. If you're financing the retrofit with a loan, or eligible for a rebate, grant or tax credit that reduces the effective upfront cost, subtract that from the cost you enter here to get a more accurate net payback period.