Heat pump vs gas furnace calculator: when does it pay off?
This heat pump vs gas furnace calculator shows whether switching pays off: enter your heat demand, energy prices, the heat pump’s seasonal efficiency, purchase cost and any incentive. You get running costs, cash outlay over the years and the year the heat pump becomes cheaper.
Source: Wikipedia – Coefficient of performance. Updated: .
How it is calculated
A heat pump pays off when the running costs it saves make up for its higher purchase price. The calculator shows after how many years that happens.
How it is calculated
- Gas: heat demand ÷ furnace efficiency × gas price.
- Heat pump: heat demand ÷ seasonal efficiency × electricity price. At a COP of 3, 20,000 kWh of heat needs about 6,700 kWh of electricity.
- Cash outlay: purchase (heat pump minus incentive) plus energy and maintenance for each year, each with its own price increase.
- Payback: the moment the cash outlay of both systems is equal. It often falls between years, so it is shown with a decimal.
What matters most
- Seasonal efficiency depends on the house, the flow temperature and the heat source – the lower the flow temperature, the more efficient.
- The ratio of electricity to gas price decides running costs: the smaller the gap, the bigger the advantage.
- A furnace that has to be replaced anyway shortens the payback, because its purchase price falls away.
All values are your assumptions, not a forecast. Incentives and prices change – enter only what applies to you today. Your entries stay in your browser.
Frequently asked questions
When does a heat pump pay for itself?
When its cumulative cost (purchase plus running) drops below that of the gas furnace. That depends on incentives, electricity and gas prices and the seasonal efficiency; the calculator shows the year.
What is the seasonal efficiency (COP)?
It states how many kWh of heat a heat pump delivers from one kWh of electricity over the year. The higher, the cheaper to run. An installer can give you a figure for your home.
How do I find my heat demand?
Your yearly gas or oil use is on the bill; for gas, 1 therm is about 29.3 kWh. Multiply it by the efficiency of your current heating, e.g. 21,700 kWh × 0.92 ≈ 20,000 kWh of heat. Hot water is already included.
Do I have to enter an incentive?
No. Enter only what currently applies to your project; otherwise leave 0. The program office can tell you the amount.
Why does the gas price rise faster in the calculator?
Because carbon pricing and network charges can push gas up. The values are examples: set the increase to 0 to compare today’s prices only.
Are my entries private?
Yes. Everything is calculated in your browser; nothing is uploaded.
Sources and legal basis
As of: · Editorial policy
Related tools
- Carnot Efficiency CalculatorCarnot efficiency calculator: maximum efficiency 1 − Tc/Th of a heat engine, plus the coefficients of performance of a Carnot refrigerator and heat pump.
- Heating cost comparisonHeating cost comparison: compare gas, oil, pellets, heat pump and electric heating from heat demand, energy price, efficiency and fixed costs. Adjustable.
- Gas units to kWhConvert gas units to kWh from your meter reading: metric m³ or imperial 100 ft³, with the calorific value and correction factor from your bill, plus cost.
- Electricity cost calculator for appliancesWork out what an appliance costs to run: enter watts, hours per day, days per week and your rate per kWh to get kWh and cost per day, month and year.
- Balcony solar calculatorBalcony solar calculator: annual output, self-consumption, savings and payback from panel power, orientation and your power price. Editable assumptions.
- Radiator size calculatorRadiator size calculator: the rated output needed for a heat demand at your flow temperature, or the real output of a radiator, for example with a heat pump.
- kg to lbs converterConvert kg to lbs and back: 1 kg = 2.2046 lb. Shows pounds and ounces, stone and pounds, grams, tons and a kg to lbs chart – exact to the legal definition.
- Pellet consumption calculatorPellet consumption calculator for pellet stoves and boilers: pounds per hour from BTU rating and efficiency, bags per day and pellets per year.
- Solar panel payback calculator: when does it pay off?Solar panel payback calculator: enter system size, cost, yield, self-use and export price to see when it pays for itself and your profit, with a chart. Free.