Reading heat pump SEER2 and HSPF2 ratings
SEER2 rates a heat pump's cooling efficiency over a whole season, and HSPF2 rates its heating efficiency over a heating season. Higher numbers mean less electricity for the same comfort, but both are lab-based averages, so they work best as a way to compare models, not to predict your bill.
What do SEER2 and HSPF2 measure?
SEER2 stands for seasonal energy efficiency ratio, second version. It is the cooling output over a typical season, measured in British thermal units, divided by the electricity used, measured in watt-hours. HSPF2, the heating seasonal performance factor, uses the same logic for heating: heat delivered over a standard season divided by electricity consumed.
The "2" marks updated test procedures that apply more realistic air-flow resistance in the ducts. A model's SEER2 or HSPF2 number is therefore lower than the older SEER or HSPF figure for the same machine, and a rating on the old scale cannot be compared with one on the new scale. Look at the label to see which edition the number follows.
How do you turn HSPF2 into a COP?
The coefficient of performance, or COP, is heat out divided by electricity in, with both in the same unit. One watt-hour is 3.412 British thermal units, so dividing an HSPF2 by 3.412 gives an average COP for the standard season. An HSPF2 of 8.5 works out to roughly 2.5, meaning about two and a half units of heat for each unit of electricity. A figure of 10 gives about 2.9.
This conversion is what the running-cost method in heat pump versus gas furnace operating cost needs. It is an average for the standard test season, though, and a cold Canadian winter pulls the real figure lower than the label average.
Why do ratings not tell the whole story in Canada?
The tests are run across set temperature conditions and a defined climate region, and no single region copies your winter. Cold-climate performance is better judged from the capacity and COP the manufacturer publishes at specific outdoor temperatures, which the cold-climate heat pump guide shows how to read. Defrost behaviour, installation quality, and duct condition also shift real efficiency.
Sizing is another factor. A unit that is too large cycles on and off and falls short of its rated efficiency, as explained in heat pump sizing for cold climates. Treat the rating as one input for the whole system, next to the output at your design temperature.
What about EER2 and other ratings?
- EER2. The energy efficiency ratio for cooling at one fixed hot outdoor condition, not a season average. It shows how the unit performs on a peak summer day.
- COP. Heat output over electricity at a stated outdoor temperature. Look for several temperatures on the data sheet.
- AFUE. The rating for fuel-burning furnaces, covered in furnace replacement, and a different measure from the seasonal heat pump figures.
- Energy label programs. Government programs set minimum levels and mark high performers. The Government of Canada energy-efficiency pages list the current requirements and qualifying models.
How should you use the numbers when buying?
Whether you are replacing an old home heating system or building new, compare quotes on the same rating scale and check the cold-temperature data for each model. A moderately higher rating can raise the price by more than it saves in energy, so weigh the extra cost against the energy saved, using your own rates. Rebate programs may set minimum ratings or require a model listed on an approved list, which is another reason to check current terms before you buy, as described in how to check heat pump rebates. The heat pump quote comparison shows what else belongs on the sheet.
Quick answers
What is a good HSPF2 rating?
Higher is better for a home, and the minimum levels in regulations and rebate programs change over time. Check the current requirements and compare the cold-temperature data for the models you are considering.
What is the difference between SEER2 and HSPF2?
SEER2 measures cooling efficiency over a season, while HSPF2 measures heating efficiency over a heating season. For a cold climate the heating number and the low-temperature data matter more.
Can I compare SEER with SEER2?
Not directly. SEER2 uses a tougher test, so the same machine gets a lower number than its old SEER rating. Compare only ratings on the same scale.
How do I convert HSPF2 to COP?
Divide the HSPF2 by 3.412. An HSPF2 of 8.5 gives a seasonal COP of about 2.5, which is an average for the test season, not for your own winter.