HSPF, HSPF2, EER and COP Heat Pump Efficiency Converter

by

Convert a heat pump HSPF, HSPF2, EER, or COP rating into a comparable energy ratio without mixing seasonal and single-condition ratings.

Use Btu/Wh for HSPF2. A bare number uses this shown unit.
Comparable seasonal COP equivalent

Did we solve your problem today?

How to use our HSPF, HSPF2, EER and COP Heat Pump Efficiency Converter

  1. Choose the exact Rating type printed on the EnergyGuide label, AHRI certificate, specification sheet, or quote.
  2. Copy its decimal number into Rating value. Use a decimal point, such as 8.1 or 3.5.
  3. Click Calculate to see the Comparable COP or EER at the same rating basis.
  4. Read the basis statement in the result: HSPF and HSPF2 produce a seasonal COP equivalent, while EER and COP stay tied to the same operating condition.
  5. Sanity-check that the rating name in the result matches your source document before comparing equipment.

Definitions

HSPF: Heating Seasonal Performance Factor. A legacy seasonal heating efficiency rating expressed in Btu/Wh.

HSPF2: A seasonal heating efficiency rating under a newer US test procedure, also expressed in Btu/Wh.

EER: Energy Efficiency Ratio. Cooling output divided by electric input at a defined operating condition, expressed in Btu/Wh.

COP: Coefficient of Performance. Useful heat moved or delivered divided by electric energy used. It is a unitless W/W ratio.

Seasonal COP equivalent: A COP-form energy ratio calculated from HSPF or HSPF2. It describes the seasonal rating basis, not performance at one temperature.

Common mistakes and quick fixes

Mistake: Selecting HSPF2 when the label actually says HSPF.
Fix: Match Rating type letter for letter. HSPF and HSPF2 are different seasonal test descriptors.

Mistake: Typing a range such as 10-12 into Rating value.
Fix: Enter one printed rating number, such as 12. Use one product or operating condition at a time.

Mistake: Using a comma as a decimal mark, such as 3,5.
Fix: Use a decimal point in Rating value, such as 3.5.

Mistake: Reading a seasonal HSPF or HSPF2 result as COP at a specific outdoor temperature.
Fix: Treat the Comparable COP or EER at the same rating basis as a seasonal energy equivalent for HSPF and HSPF2.

Mistake: Treating the converted efficiency as an electricity-cost estimate.
Fix: Check Rating type and then recalculate. Use the result only to compare efficiency ratios. A bill estimate also needs heating load, weather, runtime, electricity price, and possible supplemental heat.

Limitations & Key Assumptions / Boundary Conditions

  • HSPF and HSPF2 use different test procedures. This converter does not create a direct HSPF-to-HSPF2 estimate.
  • An HSPF or HSPF2 seasonal COP equivalent is not a measured COP at a particular outdoor temperature, indoor temperature, or part-load condition.
  • EER and COP conversions preserve the source operating-condition basis. They do not prove that two products were tested under identical conditions.
  • The calculation converts energy units only. It does not estimate heating capacity, seasonal energy use, utility cost, comfort, defrost performance, or supplemental-heat use.
  • Use the exact rating label shown by the product source. EER and EER2 are not interchangeable labels.

Methodology

Conversion method

HSPF, HSPF2, and EER are expressed in Btu/Wh. COP is a unitless W/W ratio. The converter uses 3.412141633 Btu/Wh per COP, derived from the International Table Btu and watt-hour energy definitions.

COP = rating value in Btu/Wh / 3.412141633

This formula is used when Rating type is HSPF, HSPF2, or EER. HSPF and HSPF2 results are labeled as seasonal COP equivalents. An EER result is COP at the same stated operating condition.

EER in Btu/Wh = COP * 3.412141633

This formula is used when Rating type is COP, so the displayed EER remains on the same operating-condition basis as the entered COP.

Worked example

For an HSPF2 rating of 8.1, divide 8.1 by 3.412141633. The result is about 2.374 COP on a seasonal rating basis. For a COP of 3.5, multiply 3.5 by 3.412141633. The result is about 11.942 Btu/Wh EER at the same operating condition.

Calculation boundaries

The converter accepts one positive finite rating value. It rejects zero, negative values, ranges, formulas, malformed commas, and extra numeric values. It rounds only the displayed result; the full conversion constant is retained during calculation.

Sources

  1. Federal Register :: Request Access - Federalregister