HeatWise

Heat Pump Running Cost Calculator

Convert what you already spend on heating into what a heat pump would cost to run — and see the yearly difference.

Annual heating fuel bill ($)

Current fuel price ($/kWh)

Current system efficiency (%)

Heat pump SCOP

Electricity price ($/kWh)

Heat pump running cost / year

$1,736

A positive annual saving means the heat pump is cheaper to run than your current system at these prices. Real-world savings also depend on your local tariff, weather, and the flow temperature your home needs.

Current fuel cost / year: $1,800
Annual saving: $64
Useful heat demand: 23,143 kWh

What you entered

Annual heating fuel bill ($): 1800Current fuel price ($/kWh): 0.07Current system efficiency (%): 90Heat pump SCOP: 3.2Electricity price ($/kWh): 0.24

1
Energy bought as fuel
$1800 ÷ $0.07/kWh= 25714.2857 kWh
2
Useful heat delivered (× current efficiency)
25714.2857 kWh × 90%= 23142.8571 kWh
3
Heat-pump electricity used (÷ SCOP)
23142.8571 kWh ÷ 3.2= 7232.1429 kWh
4
Heat-pump running cost
7232.1429 kWh × $0.24/kWh= $1,736
5
Annual saving vs current fuel
$1800 − $1,736= $64

Result

Heat pump running cost / year: $1,736

At these prices a heat pump would cost about $1,736/year to run — roughly $64 less than your current $1,800 fuel bill.

Heat pump running cost against your current fuel

Fuel spend converts to kilowatt-hours, then to useful heat via boiler efficiency, then to electricity via the heat pump's SCOP. Rows start from $1,800 of fuel a year at $0.07/kWh with an 85% efficient boiler.

SCOP	Electricity price	Heat demand	Heat pump kWh	Heat pump cost	Annual saving
2.6	$0.28/kWh	21,857 kWh	8,407	$2,354	-$554
3.2	$0.35/kWh	21,857 kWh	6,830	$2,391	-$591
3.2	$0.28/kWh	21,857 kWh	6,830	$1,912	-$112
3.8	$0.28/kWh	21,857 kWh	5,752	$1,611	$189
3.2	$0.20/kWh	21,857 kWh	6,830	$1,366	$434

A heat pump only saves money when its SCOP beats the ratio of electricity to fuel prices. At $0.28 electricity against $0.07 gas the ratio is 4, so a SCOP of 3.2 against an 85% boiler actually costs more to run. That is the arithmetic behind heat pumps saving money in some countries and not others, and it is why the electricity-to-gas price ratio matters more than the equipment. Carbon savings are a separate question from running cost.

A heat pump running cost calculator answers the single question most households ask before switching away from a gas boiler, oil furnace, or electric heater: will it actually be cheaper to run? Rather than starting from an abstract efficiency rating, this tool works backwards from something you already know — the amount you spend on heating fuel each year — and translates it into the electricity a heat pump would draw to deliver the same amount of warmth to your home.

The method has three steps. First, your annual fuel bill is divided by the price you pay per kilowatt-hour of that fuel to find how much energy you buy in a year. Second, that figure is multiplied by your current system's efficiency, because no boiler or furnace turns 100% of its fuel into useful heat — a modern condensing gas boiler delivers around 90%, while older systems lose more up the flue. The result is your home's real annual heat demand in kilowatt-hours. Third, that heat demand is divided by the heat pump's SCOP (Seasonal Coefficient of Performance), the ratio of heat delivered to electricity consumed averaged across a full heating season. A SCOP of 3.2 means the pump produces 3.2 units of heat for every unit of electricity, so it draws far fewer kilowatt-hours than a resistance heater would. Multiplying that electricity figure by your electricity price gives the heat pump's annual running cost, which the calculator compares directly against your existing fuel bill.

The outcome hinges on two numbers: your SCOP and the ratio between your electricity and fuel prices. Because a heat pump swaps cheaper fuel kilowatt-hours for more expensive electricity kilowatt-hours, it only saves money when its efficiency multiplier outweighs that price gap. In regions where electricity costs less than roughly three to four times the price of gas, a well-installed heat pump running at a healthy SCOP almost always comes out ahead; where electricity is very expensive relative to gas, the saving narrows or disappears. This calculator lets you test your own tariffs, current efficiency, and SCOP in seconds, so you can see whether the switch makes financial sense before committing to an installation quote — and it pairs naturally with a payback calculation once you factor in the upfront cost and any available grants.

Why SCOP matters more than the sticker COP

A heat pump's SCOP (Seasonal Coefficient of Performance) is its efficiency averaged across a whole heating season, including cold spells when it works hardest. A unit rated COP 4.0 in mild lab conditions might deliver a real-world SCOP of 3.0-3.5. Always size your running-cost estimate on SCOP, not the best-case COP.

The electricity-to-fuel price ratio decides the outcome

A heat pump replaces cheap fuel kWh with more expensive electricity kWh, but delivers 3-4× more heat per kWh. Whether it saves money depends on the ratio between your electricity price and your current fuel price. Where electricity costs less than ~3-4× your gas price, a heat pump almost always wins on running cost.

Frequently asked questions

My gas bill is $1,800/year at about $0.07/kWh — what would a heat pump cost to run?

With a 90%-efficient boiler, that $1,800 buys ~25,700 kWh of gas delivering ~23,100 kWh of heat. A heat pump at SCOP 3.2 needs ~7,200 kWh of electricity; at $0.24/kWh that's about $1,730/year — a small saving. The gap widens a lot if your electricity is cheaper or your SCOP is higher.

What SCOP should I assume for a heat pump?

A well-designed air-source heat pump in a reasonably insulated home typically achieves a SCOP of 3.0-4.0. Lower flow temperatures (35-45°C, e.g. with larger radiators or underfloor heating) push SCOP up; high flow temperatures in a poorly insulated home can drop it below 2.5.

Why might my heat pump cost more to run than my gas boiler?

If your electricity price is more than about 3.5-4× your gas price, the heat pump's efficiency advantage may not fully offset the higher unit cost — especially at a low SCOP. A special heat-pump electricity tariff, better insulation, or lower flow temperatures usually flips the result back to a saving.

How is this different from a heat pump payback calculator?

This calculator compares annual running costs (what you'll spend each year). A payback calculator adds the upfront installation cost and any grants to work out how many years of running-cost savings it takes to recover the investment. Use this one first to confirm the running cost is actually lower.