COP, HSPF, and SEER: which heat pump rating actually matters in Canada?

Pick up the brochure for any heat pump and you will see a small grid of numbers. Something like: SEER2 18.5, HSPF2 9.0, COP at 47°F = 3.8, COP at 17°F = 2.5, COP at 5°F = 1.9, EER 12.5. Plus an Energy Star logo and maybe an AHRI certificate number. If you are buying equipment that will sit in your basement for fifteen years and shape your heating bill every month, you should know what these numbers actually mean and which ones to weight in your decision.

The short answer is that the most useful number for a Canadian buyer is the COP at the coldest test temperature, ideally backed by the manufacturer's published heating capacity at –15°C or lower. Everything else on the label was designed to make American consumers compare cooling-dominated equipment, and most of it is misleading north of the U.S. border.

Here is what each rating actually measures.

COP: the one that travels well

COP stands for Coefficient of Performance. It is the ratio of useful heat delivered to electrical energy consumed, measured at a specific outdoor temperature. A COP of 3.0 at 8°C means that at that outdoor condition, every kilowatt-hour of electricity the unit draws becomes three kilowatt-hours of heat in your house.

COP is a clean, physics-based number. It does not depend on climate assumptions. A heat pump tested at –15°C produces the same COP whether it's installed in Halifax or Hamburg. That portability makes COP the most useful rating for cross-country comparison.

The catch is that COP changes with outdoor temperature. The same unit might post COP 3.8 at +8°C, COP 2.5 at –8°C, and COP 1.8 at –15°C. A manufacturer who only publishes the warm-temperature COP is hiding the part of the curve that actually matters for a Canadian winter.

What to ask for: COP at –8°C (the standard cold-weather test condition) and COP at –15°C (the harder one that separates serious cold-climate units from the rest). NRCan and Natural Resources Canada's EnerGuide Performance Verified program both list these values for certified equipment.

HSPF and HSPF2: designed for the American South

HSPF stands for Heating Seasonal Performance Factor. It is the total heat output of the unit over a notional heating season, divided by the total electricity consumed, expressed in BTU per watt-hour.

HSPF is a useful concept in principle. The problem is the "notional heating season" used to calculate it. The U.S. Department of Energy bases HSPF on "Region IV," which roughly corresponds to a moderate American climate with 2,250 heating hours per year and a design temperature around –4°C. That is not the Canadian climate.

In 2023 the rating was revised to HSPF2, which uses slightly different test conditions and a lower default duct loss. The change makes HSPF2 numbers roughly 10% lower than the old HSPF values for the same equipment, but it still uses the same Region IV climate assumption underneath.

For a Canadian buyer, HSPF and HSPF2 give you a rough ordering of equipment by efficiency but consistently overstate seasonal performance because Canadian winters are colder and longer than what the rating assumes. Use HSPF as a tiebreaker between two otherwise similar units; don't use it as a predictor of your actual operating cost.

SEER and SEER2: the cooling number

SEER stands for Seasonal Energy Efficiency Ratio. It measures cooling efficiency over a notional summer, expressed in BTU per watt-hour. SEER2 is the updated version that uses slightly higher external static pressure in testing.

SEER is genuinely useful if cooling is a significant part of your annual load. For Vancouver, Calgary, or Edmonton, where cooling demand is modest, SEER affects your bill less than COP does. For Toronto, Montréal, or Windsor, where summers are hot and humid, SEER matters more.

The Canadian minimum SEER2 for a residential air-source heat pump is 14.3. Energy Star certified units start at 15.2. The most efficient units on the market hit SEER2 22 or higher. The marginal cost of going from SEER2 16 to SEER2 22 is usually not worth it in Canadian climates because there are simply not enough cooling hours to recoup the price difference.

EER: the worst-case cooling number

EER (Energy Efficiency Ratio) is cooling efficiency at a single hot condition, usually 35°C outdoor and 27°C indoor. Unlike SEER, it does not average across a season. It tells you how the equipment performs at design cooling load. The worst summer day.

For most Canadian buyers EER is a footnote. It matters more in the southwestern U.S. and in commercial applications. Note it, then move on.

What "Cold Climate" or "CCASHP" certifications add

Beyond the manufacturer's label, there are two cold-climate-specific certifications that filter out equipment that genuinely works in Canadian winters.

The NEEP Cold Climate Air-Source Heat Pump (CCASHP) Product List, maintained by the Northeast Energy Efficiency Partnerships, lists units that meet a minimum performance threshold at –15°C and have published capacity data down to –25°C. Provincial utilities in Canada often require NEEP-listed equipment for rebate eligibility.

The CSA SB-44 standard is the Canadian equivalent. It defines a testing procedure for cold-climate performance and produces ratings that show capacity and COP at multiple low temperatures.

If a heat pump is on the NEEP list and CSA SB-44 certified, you can trust that it will perform reasonably in a Canadian winter. If a unit is not on either list, ask why before buying.

The number game on the showroom floor

Sales staff sometimes lead with the biggest number on the spec sheet. "This unit is SEER2 22, much better than the other ones." That is true for cooling. It tells you almost nothing about whether the unit will heat your home efficiently in February.

The questions to ask instead are:

• What is the published heating capacity at –15°C? Is it at least 75% of the rated 8°C capacity?
• What is the COP at –15°C? A respectable cold-climate unit should be at or above 2.0.
• What is the minimum outdoor operating temperature? Look for –25°C or colder.
• Is the unit on the NEEP CCASHP list?
• Is the unit CSA SB-44 certified for cold-climate performance?

If you cannot get clear answers to those five questions from the sales literature or the contractor, you are looking at a warm-climate heat pump being marketed to a Canadian audience. Walk away.

How to estimate your actual seasonal COP

None of the standardized ratings will tell you exactly what COP you'll see at your address. The actual seasonal average is set by your local heating-degree-days, the balance point you choose for backup heat, and the duty cycle of the unit.

A reasonable rule of thumb for a cold-climate ASHP installed in Atlantic Canada or southern Ontario is a seasonal COP between 2.4 and 2.8. For a milder climate like Vancouver or Victoria, 2.8 to 3.3. For Prairie cities like Edmonton or Winnipeg, 2.0 to 2.4. For the territories, 1.8 to 2.2 with significant backup heat usage.

Our check tool uses values in these ranges by default based on the heating-degree-days of your city. If you have a contractor's specific F280 calculation, you can refine the estimate.

The summary

If you only have time to look at one number, look at COP at –15°C. If you have time for two, add cold-climate certification (NEEP or CSA SB-44). Everything else is either useful but secondary (SEER, HSPF) or genuinely background noise for Canadian buyers (EER, HSPF Region IV assumptions).

A heat pump is a long-lived piece of equipment. Spending an hour reading spec sheets before you buy is a small investment that pays back across the next fifteen years.