Heat Pump Seasonal Performance Factor Calculator

Compute a defensible seasonal performance factor (SPF) for an air- or ground-source heat pump. Sum all useful heat delivered and the electrical inputs (compressor, backup resistance, pumps, and fans) to benchmark seasonal efficiency with the same methodology utilities and building codes expect.

Total thermal energy delivered to the conditioned spaces over the analysis season in kilowatt-hours.
All compressor and control electricity measured at the heat pump supply over the same season.
Leave blank to assume no resistance backup. Enter the kWh supplied by strip heaters or electric boilers.
Leave blank to default to 0 kWh. Include circulation pumps, crankcase heaters, or ERV fans you want inside SPF.

Efficiency benchmarking aid only; confirm regulatory reporting rules in your jurisdiction before publishing results.

Examples

  • Heat delivered 42,500 kWh, compressor draw 12,000 kWh, backup 250 kWh, auxiliary 450 kWh ⇒ Seasonal performance factor 3.35 with 12,700.00 kWh of electricity consumed.
  • Delivered 18,600 kWh, compressor electricity 5,800 kWh, no backup, auxiliary default ⇒ SPF 3.21 and 5,800.00 kWh electric input.

FAQ

Does SPF differ from COP?

Coefficient of performance (COP) is an instantaneous metric, whereas SPF aggregates delivered heat and electricity across a full season or year.

How should I handle defrost cycles?

Ensure defrost power is included in the metered compressor electricity; the heat credited during defrost remains part of the delivered total.

Can I compare SPF between buildings?

Yes—document the loads and auxiliary inclusions so reviewers understand whether domestic hot water, ventilation fans, or crankcase heaters were part of the calculation.

Additional Information

  • Result unit: ratio (dimensionless).
  • SPF aligns with European SCOP reporting when auxiliary energy is included in the denominator.
  • Electric inputs should cover the same seasonal window as the metered heat output for comparability.

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