Heat pump efficiency
Heat Pump Operating Cost Calculator
Estimate electricity use and cost from a stated thermal load, operating time, COP at that condition, and your electricity rate.
Operating inputs
Use a load and COP that apply to the same operating condition. Currency is shown as a generic unit.
What the result means
The calculator converts useful thermal energy during the stated run time into electrical energy using the COP you enter, then applies the electricity rate. Heating mode also prices the same delivered heat at COP 1 as an electric-resistance comparison.
Formula and units
US customary: delivered thermal energy (kWh thermal) = load (BTU/h) × hours ÷ 3,412.141633
COP is a dimensionless ratio of useful heating or cooling delivered to electrical work input. It is not a seasonal rating.
Inputs
| Input | Use | Limit |
|---|---|---|
| Thermal load | Useful heating or cooling rate at the condition reviewed | Use a documented load, not nominal equipment capacity alone. |
| Operating hours | Hours at that load and COP | Part-load cycling, defrost, and weather variation are not modeled. |
| COP | Useful output divided by electrical input | Use manufacturer or measured data for the same mode and condition. |
| Electricity rate | Your marginal energy charge per kWh | Demand, fixed, and time-of-use charges may differ. |
Worked example
A 24,000 BTU/h heating load for 8 hours delivers 192,000 BTU, or 56.27 kWh thermal. At COP 3, electricity use is 18.76 kWh. At 0.15 currency/kWh, estimated operating cost is 2.81 currency. Resistance heat at COP 1 would use 56.27 kWh and cost 8.44 currency under the same rate.
Assumptions and limitations
This is a scenario calculator, not an annual energy model. COP changes with indoor and outdoor conditions, load, defrost operation, controls, and installation. Do not convert SEER2 or HSPF2 to a point COP for this tool: those are seasonal ratings. Use a documented point COP, or use a whole-season model that matches the rating and climate data.
Use the right sequence
First calculate or obtain the building load. Then check whether equipment can meet that load at design conditions. Use this calculator only to test the energy and cost implication of an identified operating scenario.
Frequently asked questions
Can I enter nominal tonnage as the load?
Only if it is the useful load actually delivered at the operating condition. A nominal capacity label alone does not describe building demand, cycling, or point efficiency.
Why does heating show a resistance comparison?
Electric resistance heat delivers approximately one unit of heat per unit of electricity (COP 1). This is not a gas, oil, or dual-fuel comparison.
Can this calculate electrical breaker size?
No. Circuit decisions require the equipment nameplate, manufacturer instructions, applicable electrical code, and qualified review.
Related resources
- Heat Pump COP and Operating Cost Guide
- Heat Pump Efficiency Ratings Reference
- HVAC Load Calculator
- BTU Calculator
- BTU/h vs kW
Sources and scope
Use manufacturer data and the exact rating condition for the COP input. These sources define the relationship and unit basis; they do not supply a universal COP or operating cost.