Heat Pump Calculator
What a heat pump costs to run for heating or cooling, from the heat you need, its COP, SCOP or SEER and your electricity price, against a gas, oil or older system, and the yearly saving.
Result…
How it's calculated
Heating: heat pump cost = heat ÷ SCOP × electricity price · current cost = heat ÷ efficiency × fuel price Heat from fuel = fuel kWh × efficiency; fuel kWh = bill ÷ fuel price Break-even electricity price = fuel price × SCOP ÷ efficiency Cooling: cost = cooling kWh ÷ SEER (W/W) × electricity price; SEER (W/W) = SEER (BTU/Wh) ÷ 3.412142
A heat pump moves heat rather than making it, so each kWh of electricity delivers several kWh of heat: that ratio is the COP, and the SCOP is its average over a heating season. A boiler or heater turns fuel into heat at its efficiency, so the heat your home needs is the fuel it burns times that efficiency. Both systems are compared on the same heat. For cooling the ratio is the EER or SEER, and here the name hides two units. In Europe and many other places it is in W/W (kW of cooling per kW of electricity, like a COP). On US labels it is in BTU per watt-hour, and 1 W = 3.412142 BTU/h (the International Table BTU of 1055.05585262 J), so a W/W figure is the BTU/Wh figure divided by 3.412142. Always compare two ratings in the same unit.
Your numbers, step by step
About the Heat Pump calculator
This heat pump calculator compares what a heat pump costs to run with your current heating or cooling, using only the prices and ratings you enter. For heating, give the heat your home needs a year, or the fuel your boiler uses, or simply your yearly heating fuel bill, with the current system's efficiency and fuel price per kWh. Add the heat pump's SCOP or COP and your electricity price to see both running costs, the yearly saving and the electricity price at which they break even. For cooling, enter the cooling needed or the unit's capacity and hours, and the SEER or EER of the new and old units, with the unit made explicit: W/W or the BTU/Wh used on US labels. Every step is shown.
How to use it
- Choose “Heating” or “Cooling” under “Use”.
- For heating, pick what “I know” and enter the heat demand, the fuel used or the “Heating fuel bill a year”, then the “Current system efficiency” and “Current fuel price per kWh”.
- Enter the “Heat pump SCOP or COP”, using the seasonal figure for your climate where you can.
- For cooling, pick the “Efficiency rating unit” first, then enter the “New system SEER” and “Old system SEER” in that same unit.
- Enter your “Electricity price per kWh” and read the yearly saving or extra cost.
Worked example
A yearly heating fuel bill of 1,200 at 0.08 per kWh means 1,200 ÷ 0.08 = 15,000 kWh of fuel. At 88% efficiency that gives 13,200 kWh of heat. A heat pump with a SCOP of 3.2 needs 13,200 ÷ 3.2 = 4,125 kWh of electricity, which at 0.24 per kWh costs 990 a year, a saving of 1,200 − 990 = 210. The two cost the same when electricity is 0.08 × 3.2 ÷ 88% = 0.291 per kWh.
Updated
Questions people ask
How do I calculate the running cost of a heat pump?
Divide the heat you need in kWh by the heat pump's SCOP or COP to get the electricity it uses, then multiply by your price per kWh. The calculator does the same for your current system using its efficiency and fuel price.
What is the difference between COP and SCOP?
COP is the heat out divided by the electricity in at one set of test conditions. SCOP averages that over a heating season, so it is the better figure for a yearly running cost. Both fall as the outdoor temperature drops or the flow temperature rises.
Is a SEER of 18 the same as a SEER of 18 in Europe?
No. US labels give SEER in BTU per watt-hour, while European and many other labels give it in W/W. Since 1 W = 3.412142 BTU/h, a SEER of 18 BTU/Wh is about 5.28 W/W. Comparing the two directly is a common mistake.
At what electricity price does a heat pump stop saving money?
When electricity costs more than fuel price × SCOP ÷ boiler efficiency per kWh. The calculator shows this break-even price for your own figures.
What does this heat pump estimate not include?
Standing charges, servicing, installation, grants and changes in price or weather are left out, and real efficiency depends on the design and settings. For sizing the heat output, the BTU calculator helps; for a decision, ask an accredited installer for a heat-loss survey and an independent adviser for the money side.