HVAC & Energy

COP and EER Calculator

Convert same-condition COP and EER or calculate efficiency from measured powers. Compare SI/US results and review the method, assumptions and related references below.

Change any input to update the calculation. Unit changes preserve the physical quantity.

CALCULATION SETUP

Inputs

Preset

Same-condition COP

Electrical input at the same condition

Need an input value?

Single & Three-Phase Power Reference ↗

Calculated locally in your browser. No sign-up or input upload.

YOUR CALCULATION

Results

COP

3 W/W

EER

10.2364 BTU/(Wh)

Useful thermal output

3 kW10,236.4249 BTU/h

Electrical input

1 kW

Calculation breakdown

Result interpretation: Convert same-condition COP and EER or calculate efficiency from measured powers

Assumptions & checks

Match operating point and measurement boundaries for both powers. No seasonal-rating conversion or prediction of low-temperature performance.

Formula

Convert same-condition COP and EER or calculate efficiency from measured powers

COP=thermal watts/electrical watts; EER=COP×3.412141633 BTU/(Wh). This fixed conversion does not apply to SEER, SEER2 or HSPF seasonal ratings. Worked example: 3 kW useful thermal output / 1 kW electrical input gives COP 3 and EER 10.2364 at the same operating condition.

Worked example

Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.

Inputs

Same-condition COP: 3
Electrical input at the same condition: 1 kW

Result

COP: 3 W/W
EER: 10.2364 BTU/(Wh)
Useful thermal output: 3 kW
Electrical input: 1 kW

Related calculators

Continue your workflow with a related calculation.

View all HVAC & Energy calculators

HVAC & Energy

Heat Pump Running Cost Calculator

Estimate heat-pump kWh, annual and average monthly running cost from heat demand or runtime, editable COP/SCOP, tariff and auxiliary electricity.

HVAC & Energy

Air Cooling Load Calculator

Calculate sensible and latent cooling from an entered moist-air process or reverse airflow. SI/US units, clear methods and related references.

Electrical

Electrical Power Calculator

Solve electrical input power, current or supply voltage for DC and balanced AC loads. SI/US units, clear methods and related references.

Technical references for this calculation

Reference lookupDry Air Properties Table Reference lookupSingle & Three-Phase Power Reference

Frequently asked questions

What does this result tell me?

Match operating point and measurement boundaries for both powers. No seasonal-rating conversion or prediction of low-temperature performance.

How can I check the calculation?

Worked example: 3 kW useful thermal output / 1 kW electrical input gives COP 3 and EER 10.2364 at the same operating condition. Review each stated input and unit; use project-specific values rather than treating the editable example as a requirement.

Reference data & method sources

DOE heat pump performance terminology
COP and EER are same-condition efficiency measures. Seasonal SEER/HSPF ratings cannot be converted by a constant.
NIST SI conversion factors
SI/US dimensional conversions. Geometry and energy balances are stated explicitly, not attributed to a design standard.