Heat Pump COP and Efficiency Calculator

Calculate the Coefficient of Performance (COP), Heating Seasonal Performance Factor (HSPF), and Energy Efficiency Ratio (EER) for heat pumps operating in heating and cooling modes.

Operating Temperatures

Indoor air temperature (heating) or outdoor condenser temperature (cooling)
Outdoor source temperature (heating) or indoor evaporator temperature (cooling)

Power & Heat Transfer (Optional)

W
Electrical power consumed by the compressor
Measured heat delivered (heating) or heat removed (cooling)

Formulas Used

Carnot COP (Heating Mode):

COPH,Carnot = TH / (TH − TC)

Carnot COP (Cooling Mode):

COPC,Carnot = TC / (TH − TC)

Actual COP (from measured values):

COPactual = Q / Win

Where Q = heat delivered or removed (W), Win = electrical power input (W)

Carnot Efficiency:

ηCarnot = COPactual / COPCarnot × 100%

Energy Efficiency Ratio (EER, cooling):

EER = QBTU/hr / Win,W  [BTU/(hr·W)]

Heating Seasonal Performance Factor (HSPF):

HSPF ≈ COP × 3.41214  [BTU/(hr·W)] — steady-state approximation

All temperatures must be in Kelvin (absolute scale) for thermodynamic calculations.

Assumptions & References

  • References: ASHRAE Handbook — Fundamentals (2021); Çengel & Boles, Thermodynamics: An Engineering Approach, 9th ed.; U.S. DOE ENERGY STAR Heat Pump Program.

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