Heat Pump Savings Calculator

How to use the heat pump savings calculator

Enter three numbers and you get back what a heat pump saves you each month on heating: the monthly energy a plain resistance electric heater would use to deliver your heat, the heat pump’s COP, and your electricity rate. The tool turns those into the monthly dollar saving, the kilowatt-hours the heat pump actually draws to make the same heat, and the annual saving. It answers one question only — “for the same warmth, how much less does a heat pump cost to run than electric-resistance baseboards or strips?” — and it answers it in money you can put on a calendar.

Start with the resistance baseline in kWh. This is the energy a 100%-efficient electric heater — baseboards, a fan heater, or the resistance strips in an older system — would burn in a month to keep you warm. If you already heat that way, read it straight off your bill; if you’re shopping, the default of 1,000 kWh is a fair winter month for a mid-size home. Whatever you enter, it represents the heat you need, not the way you make it, so the same figure is the honest starting point for both heaters. If you only know the heat in another unit, the companion heating-cost-calculator will turn a baseboard or furnace load into the monthly kWh figure to drop in here.

Next set the COP — the heat pump’s coefficient of performance, the efficiency multiplier at the centre of the whole calculation. A COP of 3.0, the default, means the unit is roughly 300% “efficient”: for every one unit of electricity it consumes, it moves about three units of heat into your home. It manages that because it doesn’t burn electricity to make heat the way a resistance coil does — it runs a refrigeration cycle in reverse to pump heat that already exists in the outdoor air indoors, so most of the warmth is free ambient heat relocated rather than energy converted. Higher COP, lower running cost: nudge it to 4.0 and the saving climbs.

One honest caveat about COP: it falls as it gets colder. A heat pump rated COP 3 in mild conditions may drop well below that on a deep-winter night, because there’s less ambient heat outside to move and the unit works harder to find it. Many units fall back to built-in resistance strips in extreme cold — heating at COP 1, no better than baseboards — so your real seasonal saving can land lower than a single nameplate COP suggests. If your winters are harsh, run the tool again with a more conservative COP to see the colder-weather picture, and treat the headline number as the mild-weather best case.

Last, the rate. The US residential average is about 17.5¢/kWh as of 2026, but rates vary widely by state, so use the rate from your own bill rather than the default. Then read the three outputs together: the monthly saving is the headline — the dollars the heat pump keeps in your pocket each month for the same heat — the heat-pump kWh shows how little energy it draws to get there, and the annual saving multiplies the month by twelve. One thing this tool deliberately does not do is account for the purchase and installation cost of the heat pump or work out a payback period: it is the running-cost saving only, the production side of the ledger. To weigh a heat pump against burning gas instead, reach for the gas-vs-electric-heating-calculator.

The formula

The saving is the gap between two ways of making the same heat. Cost the resistance heater at full price — every kilowatt-hour billed — then cost the heat pump, which needs only a fraction of that energy because its COP lets one unit of electricity move several units of heat. Subtract the second from the first:

resistance cost = heating kWh × rate
heat-pump kWh = heating kWh ÷ COP
monthly saving = resistance cost − (heat-pump kWh × rate)

Worked example with the defaults — 1,000 kWh of heat at a COP of 3.0 and a $0.175/kWh rate. The resistance heater costs 1,000 × $0.175 = $175.00 a month. The heat pump needs only 1,000 ÷ 3 = 333.3 kWh, which at the same rate costs 333.3 × $0.175 = $58.33 a month. The monthly saving is $175.00 − $58.33 = $116.67, or about $1,400 a year. Raise the COP to 4 and the heat pump draws even less, lifting the monthly saving to $131.25.

COP is why a heat pump beats a resistance heater so decisively: a resistance coil converts electricity to heat at a fixed 1-to-1, while a heat pump moves roughly its COP in heat for each unit of electricity, so a COP of 3 does the same job for about a third of the energy. The catch is that COP is not constant — it falls as outdoor temperatures drop, and many units switch to resistance strips (COP 1) in deep cold, so the seasonal average can sit below the nameplate figure and the real saving with it. The result is running cost only; it does not include the price of buying or installing the heat pump.

Frequently asked questions