SEER2 Ratings and the 5 Numbers Ontario's Rebate Tests

The numbers on an HVAC quote are efficiency ratings, and each one answers a different question. AFUE is the share of a furnace's gas that becomes heat. SEER2 is cooling efficiency over a whole summer, and EER2 is cooling efficiency at one hot test point. HSPF2 is heating efficiency over a whole winter, and COP is how much heat a heat pump moves for each unit of power at one set temperature. Higher is better on all five. In Canada, a split central air conditioner made since January 1, 2023 must reach 13.4 SEER2. A split heat pump must reach 14.3 SEER2 and 6.0 HSPF2. A typical house gas furnace made since July 3, 2019 must reach 95% AFUE. Ontario's heat pump rebate asks for more than the legal floor. And every rating on a quote belongs to one matched set of equipment, which is why the AHRI number matters more than any single figure.

What each number on your quote measures

• AFUE (annual fuel utilization efficiency) is for furnaces. It is the share of the fuel's energy that becomes heat over a heating season. Natural Resources Canada notes it is "a seasonal measure of fuel efficiency only" and leaves out the electricity that runs the fan and controls. Canada caps furnace fan energy separately, with a fan energy rating limit.
• SEER2 (seasonal energy efficiency ratio 2) is for air conditioners, and for heat pumps when they cool. It is the total cooling over a normal cooling season divided by the electricity used.
• EER2 (energy efficiency ratio 2) is cooling efficiency at one steady test condition, not a season. The Mitsubishi sheet we read rates it at 95°F (35°C) outdoors.
• HSPF2 (heating seasonal performance factor 2) is for heat pumps when they heat. It is the heat delivered over a heating season divided by the electricity used. It is always worked out for a climate region. NRCan says ratings are typically reported for Region IV, a climate like the US Midwest, while Region V covers most of the southern half of the provinces. Canada's rules use Region V.
• COP (coefficient of performance) is heat moved divided by power used, at one temperature. NRCan's heat pump guide gives the example: 1 kW of electricity moving 3 kW of heat is a COP of 3.
• Heating capacity at 8.3°C (47°F) is the unit's rated heating output in Btu per hour. Every 12,000 Btu per hour is one ton, and it sets the rebate.

Why the numbers got smaller in 2023

On January 1, 2023, the test changed. AHRI, the industry body that certifies ratings, says the new test raises the external static pressure by up to five times. That is the push-back from real ductwork. So the same machine now scores lower. AHRI's own tables show the gap: a 13.4 SEER2 air conditioner is the old 14 SEER, and a 14.3 SEER2 heat pump is the old 15 SEER.

Canada adopted the same test on the same date, with two differences from the US version. Heating is scored for Region V, as Canada's older HSPF rule already was, not the US Region IV. And every single-phase split heat pump (the kind a house uses) made on or after January 1, 2025 must also be tested at -15°C, with its heating capacity and COP at that temperature reported to NRCan.

So never compare an old SEER figure with a SEER2 figure. Even NRCan's own heat pump booklet, updated December 24, 2025, still lists a minimum of 14 SEER and 7.1 HSPF. Those are the pre-2023 rows of the regulation, not today's rule. Ontario's own product rule, O. Reg. 509/18, applies the same federal standards to air conditioners, heat pumps and gas furnaces made on or after January 1, 2025.

Canada's minimums and Ontario's rebate bar

The legal floor comes from the Energy Efficiency Regulations, 2016, last amended October 9, 2025. The rebate bar comes from the Home Renovation Savings heat pump requirements, the program Enbridge Gas and Save on Energy run.

Those are the five numbers the rebate checks, and a unit must pass all five. It must also be an active cold-climate model on NRCan's list, run at three or more speeds or continuously variable, and be sold in Canada. ENERGY STAR is not one of the conditions for an air source heat pump. That matters because ENERGY STAR's own heating targets, such as 8.1 HSPF2 for a ducted cold-climate unit, are scored for Region IV. They can't be laid against the rebate's 6.6.

The heat pump amounts are paid per ton of rated heating capacity:

Pre-approval is mandatory: installations done before approval are not eligible. What the rebate is worth for your fuel, and who qualifies, is its own question.

A rating belongs to a matched pair, not a box

A split system is at least two pieces: the outdoor unit and an indoor coil or air handler, sometimes with a furnace. AHRI certifies the combination and gives it a reference number. The rating belongs to that combination. The rebate requirements say all the parts "must be compatible and listed together under the same AHRI number", except coils-only systems that pair with an existing furnace.

We looked up three heat pumps that GTA installers sell in NRCan's searchable product list on September 28, 2026. Each outdoor unit is listed with several indoor partners, and the ratings move with the partner.

Paired with one third-party coil, the Kepler outdoor unit is listed at 15.0 SEER2 and 6.35 HSPF2. Both miss the rebate floor. With Kepler's own air handler it reaches 16.3 and 8.0. A quote that names only the outdoor unit has not told you its rating.

One GTA quote, read end to end

Bison Air in Vaughan lists a 3-ton Mitsubishi Zuba-Central as outdoor unit PUZ-AK36NLHZ-U1 with air handler PVA-AA36NL-U1. Its page prints SEER2 21.2, EER2 12.1 and HSPF2 7.5. It also claims "100% capacity" at -15°C and "80% capacity" at -25°C. It prints no AHRI number.

1. Find the pair. NRCan lists this exact pairing as AHRI 215712216, status Active, grouped as a cold-climate heat pump. The AHRI Directory returns one match for that number.
2. Match the cooling figures. NRCan lists 21.2 SEER2. Mitsubishi's own submittal sheet prints SEER2 21.20 and EER2 12.10, which agree.
3. Name the heating region. NRCan lists HSPF2 9.2 for Region IV and 7.5 for Region V. Mitsubishi's sheet prints only "HSPF2 [IV] 9.20". Bison's 7.5 is the Canadian figure, though the page doesn't say so. A quote that prints 9.2 is not lying, but it is quoting the US climate.
4. Check the cold figures. NRCan lists a COP of 2.1 at -15°C at full output, and 95% capacity kept. Mitsubishi's sheet shows why: 38,000 Btu per hour at 5°F against a 40,000 rating at 47°F, and 38,000 ÷ 40,000 = 95%. The "100%" claim doesn't say what it is measured against. The -25°C claim can only be checked against the maker: its sheet gives 30,800 Btu per hour at -13°F, and 30,800 ÷ 40,000 = 77% of the rating. Neither Canada's heat pump standards nor Ontario's rebate uses a -25°C figure.
5. Run the rebate test. HSPF2 7.5 clears 6.6. SEER2 21.2 clears 15.2. The 40,000 Btu per hour clears 12,000, a COP of 2.1 clears 1.8, and 95% clears 70%. It passes all five numbers, and NRCan lists it as Active.
6. Work out the tonnage. The rebate uses rated heating capacity, not the "3 ton" in the name, and the program's help page says tonnage is not rounded. That is 40,000 ÷ 12,000 = 3.33 tons. In a home heated by electricity, oil, propane or wood, $1,250 × 40,000 ÷ 12,000 = about $4,167. For an Enbridge gas customer, $500 × 40,000 ÷ 12,000 = about $1,667, under the $2,000 cap.

What 25 GTA installers print

We read the heat pump and air conditioner pages of 25 GTA installers on September 28, 2026, and recorded what each one prints.

Twelve of the 25 print a cooling rating. Seven of those 12 still rate equipment they sell or recommend on the pre-2023 SEER scale, three of them with no SEER2 figure at all. Imperial Heating's air conditioner page says "the minimum SEER rating for new AC units sold in Canada is 14 SEER." That is the same bar on the old scale; the regulation itself is written as 13.4 SEER2. HVAC Market's Kepler page gives a "SEER ... rating of 21" in its description and "SEER2 15.2" in its specification table, while NRCan lists that outdoor unit from 15.0 to 16.3 SEER2.

Five installers print an HSPF2 figure, and only City Home Comfort says which region it is. It is also the only one of the 25 that prints AHRI numbers, one for each matched pair of its Midea system.

Two installers give rebate rules of thumb that don't match the program. LG Home Comfort says to target SEER2 of 15 and HSPF2 of 8.5 for "better rebate eligibility", and Constant Home Comfort says to look for "a minimum HSPF2 of 8.5 and SEER2 of 15". The floor is 15.2 SEER2, so 15 falls short. Neither page names a region, and on the Region V scale the program uses, an 8.5 cut-off would rule out the Mitsubishi pairing above, which qualifies at 7.5.

What your quote should list, and how to check it

The rebate program writes the minimum down for you. Its requirements define the work order, meaning the quote or estimate, as including "brand name, AHRI number, and model number". Its sample invoice adds the tonnage. Ask for that on any quote, rebate or not:

1. The brand and full model number of the outdoor unit, the indoor coil or air handler, and the furnace if it is part of the pairing.
2. The AHRI reference number for that exact pairing.
3. SEER2, EER2 and HSPF2, with the HSPF2 marked Region V.
4. For a heat pump, the heating capacity at 8.3°C and the COP at -15°C.
5. For a furnace, the model number and its AFUE. NRCan lists Goodman's GMVC96 furnaces, which EcoFrost prices as a 96% model, at 96.1 AFUE.

Then check it. NRCan's product list, updated quarterly and last on August 7, 2026, asks homeowners to get "the AHRI number, the brand name, and the model numbers" into the quote so the system can be looked up, and it shows the Region V heating score. The AHRI Directory searches by reference or model number, and its Verify Certificate page checks a printed certificate. If the quote doesn't match, ask why before you sign. A furnace's installed price and permit are separate questions from its AFUE.