About this tool
Heat Pump COP / SEER & Running Cost Calculator is a free, in-browser tool that translates the ratings on a heat pump's spec sheet into a plain coefficient of performance (COP) and compares what it costs to run against electric resistance and gas heating. All maths runs in your browser.
COP is heat delivered divided by electricity consumed, so a COP of 3 means three units of heat per unit of power. The tool converts between the common ratings: COP ≈ HSPF / 3.412, COP = EER / 3.412, and a cooling COP from SEER, or you can enter measured heat output and electric input directly (COP = output / input). It also reports the equivalent HSPF, EER and a percentage efficiency (COP × 100).
Enter an annual heat demand and your electricity and gas rates and it estimates the heat pump's yearly running cost — (demand / COP) × rate — alongside pure electric resistance and a gas furnace (adjusted for AFUE), then shows the saving. Use it to decide whether a heat pump beats your current system.
Frequently asked questions
How do HSPF, SEER, EER and COP relate?
They all measure efficiency but in different units. COP is a unitless ratio of heat out to energy in. HSPF and SEER are seasonal ratings in BTU per watt-hour, and EER is an instantaneous BTU/Wh rating, so dividing any of them by 3.412 gives the equivalent COP. HSPF describes heating performance; SEER and EER describe cooling.
Why is a COP of 3 better than a 95% gas furnace?
A COP of 3 delivers 300% as much heat as the electricity it draws, because a heat pump moves existing heat rather than creating it. A 95% furnace only delivers 95% of the fuel's energy. Whether it is cheaper to run still depends on your local electricity price versus gas price, which the cost comparison works out for you.
Does COP stay constant?
No — a heat pump's real-time COP falls as it gets colder outside, which is exactly why the seasonal HSPF exists to average a whole heating season. The single COP here is a design figure; expect better on mild days and worse in a cold snap.
What annual heat demand should I enter?
Use the heat energy your home actually needs in a year, in kWh — you can get this from the Home Heat Loss calculator (annual heat energy output) or from a past heating bill converted to kWh. The cost comparison scales linearly with it.
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