Measured Heat Pump COP

Calculate operating heating COP from simultaneously measured heat delivery and total electrical input.

How this calculation works

Heating COP is the ratio of delivered heating power to the electrical power used to produce it at the measured operating point. Enter simultaneous thermal output and total electrical input readings with the same system boundary, including the auxiliaries that belong within that boundary. The powers are entered in kilowatts and the duration in hours. Their ratio is dimensionless; multiplying each power by duration gives delivered thermal energy and consumed electrical energy in kWh. A COP of four means four units of heat are delivered for each unit of measured electrical input. The period energy estimates assume constant powers. Defrost, transients and measurement uncertainty can change the apparent ratio, and this operating-point calculation is not a seasonal or certified performance rating.

Inputs and units

Delivered heating power (kW)
Total electrical input (kW): Include auxiliaries within the chosen measurement boundary
Operating duration (h)

Method and formula

Heating COP = delivered thermal power/electrical input power; energy = power × operating hours.

Worked example

Example inputs

Delivered heating power: 12 kW
Total electrical input: 3 kW
Operating duration: 8 h

Calculation steps

Divide simultaneous heating output by electrical input: COP = 12/3 = 4, dimensionless.
Calculate delivered thermal energy over 8 h: 12 × 8 = 96 kWh.
Calculate consumed electrical energy over the same 8 h: 3 × 8 = 24 kWh.

Example results

Heating COP: 4 1
Delivered thermal energy: 96 kWh
Consumed electrical energy: 24 kWh

Assumptions

Thermal and electrical power describe the same time and system boundary
Constant powers during the entered duration

Limitations

An operating-point ratio is not a seasonal rating or certified performance
Measurement uncertainty and defrost can materially affect the result

Sources

U.S. DOE / NREL: Air Source Heat Pumps in Cold Climates: Slide 5, heating COP definition