SEER2 and HSPF2 Explained Ontario 2026: What the Ratings Actually Mean and Why the '2' Matters

What SEER2 Measures (Cooling Efficiency)

SEER2 stands for Seasonal Energy Efficiency Ratio 2. It is the total cooling output of an air conditioner or heat pump over a typical cooling season, measured in BTUs, divided by the total electrical energy it consumed during that same season, measured in watt-hours. The higher the number, the more cooling you get per dollar of electricity.

A 14.3 SEER2 unit running an average Ontario summer produces the same amount of cooling while using roughly 13 percent less electricity than an old 10 SEER unit from the early 2000s. Most residential equipment sold in Ontario in 2026 lands somewhere between 13.4 SEER2 (the US DOE southern minimum) and 26 SEER2 (top-tier variable-speed ductless units from Napoleon, Daikin, and KeepRite).

SEER2 is a seasonal average, not a peak-load number. A 22 SEER2 unit does not produce 22 times more cooling than it consumes at any given moment. It averages 22 across a full season of mild mornings, hot afternoons, and part-load operation. For peak-heat performance, the companion number is EER2 (Energy Efficiency Ratio 2), which measures instantaneous efficiency at 95 F outdoor temperature. Ontario ENERGY STAR requires 12.0 EER2 for a split central AC and 11.7 EER2 for a split heat pump.[2]

What HSPF2 Measures (Heating Efficiency)

HSPF2 stands for Heating Seasonal Performance Factor 2. Same idea as SEER2, but for heating. It is the total heat output of a heat pump over a typical heating season, divided by the total electricity it drew to deliver that heat, both in BTUs. Higher is better.

A 7.8 HSPF2 unit (the ENERGY STAR split heat pump minimum) is roughly equivalent to an old 8.5 HSPF unit under the pre-2023 test. A 10 HSPF2 unit is premium-tier cold-climate territory. The top of the residential market in 2026 hits 11 to 12 HSPF2 on variable-speed inverter models from Carrier, Lennox, and KeepRite.

HSPF2 is a single number meant to capture a full heating season, which means it smooths across mild fall days, deep winter cold snaps, and shoulder-season defrost cycles. It is useful for comparing units at a glance, but for an Ontario home the question of how the unit performs specifically at minus 15 Celsius matters more than the seasonal average, because that is when you will most notice the difference between a good unit and a mediocre one. That is where COP at minus 15 comes in, covered later.

The M1 Test Standard Change (Why Old vs New Numbers Differ)

The ratings changed in January 2023 because the test changed, not the equipment. The US Department of Energy updated the test procedure for residential central AC and heat pumps from the old SEER/HSPF method (AHRI Standard 210/240 with an M/M1 option) to the new M1 mandatory procedure (AHRI Standard 210/240-2023).[5]

The main change: external static pressure during the test went up. The old test used a static pressure that assumed a very clean, low resistance duct system, which does not match what most homes actually have. The new M1 test uses a higher external static pressure that is closer to a realistic ducted installation with filters, bends, and return grilles. Higher static pressure makes the blower work harder, which uses more electricity, which lowers the measured efficiency.

The cooling-side impact is roughly 4.5 percent lower. A unit that tested at 14.0 SEER under the old standard typically comes in at 13.4 SEER2 under M1. A 16 SEER unit becomes roughly 15.2 SEER2. A 20 SEER unit becomes roughly 19 SEER2. Budget and entry-level models are dropping by a similar fraction as premium units.

The heating-side impact is larger because M1 also changed how defrost cycles are credited against heating output. HSPF2 numbers typically come out 6 to 10 percent lower than the equivalent old HSPF. An 8.5 HSPF unit generally becomes around 7.8 HSPF2. A 10 HSPF premium unit often drops to roughly 9.0 to 9.3 HSPF2.

If you are comparing a quote today against an old brochure or an older unit in your neighbour's house, remember that the numbers are not apples to apples. Either convert the old rating down by 4.5 percent (cooling) or 8 percent (heating) to estimate the SEER2/HSPF2 equivalent, or ask the contractor for the current M1-tested AHRI number for the unit in question.

ENERGY STAR Thresholds for Ontario Eligibility

For rebate eligibility and ENERGY STAR qualification in Ontario, the thresholds that matter in 2026 are:[2]

Ontario's Home Renovation Savings Program (HRS) cross-checks against the NRCan Canada Greener Homes product list and the NEEP cold-climate list.[1]For cold-climate heat pumps, the HRS requires at least 70 percent capacity retention at minus 15 Celsius compared to 8.3 Celsius, plus a variable-speed compressor, plus COP of at least 1.8 at minus 15 Celsius (slightly stricter than the US ENERGY STAR Cold Climate 1.75 threshold).[6]

Reading a Spec Sheet

The only spec sheet that legally counts is the AHRI Certificate of Product Ratings. AHRI certificates are searchable for free at ahridirectory.org. Every residential central AC, split heat pump, and single-package heat pump sold in North America has one.[4]

An AHRI certificate for a heat pump shows:

• Outdoor unit model number and indoor unit model number. This matters because the same outdoor unit paired with different indoor units produces different ratings. A Carrier 24VNA6 outdoor with a high-end air handler can test at 18 SEER2, while the same outdoor with an older furnace-and-coil combo might test at 15.8 SEER2. Always match the quote against the combination on the certificate.
• Cooling capacity in BTU/hour at AHRI rating conditions (95 F outdoor, 80 F indoor)
• SEER2 and EER2
• For heat pumps: Heating capacity at 47 F and heating capacity at 17 F in BTU/hour
• For heat pumps: HSPF2for Region IV (southern US) and/or Region V (cold-climate, which is the number that matches Ontario's heating season)
• Sound rating in decibels for the outdoor unit

Marketing brochures often quote an "up to" rating. The "up to" number is typically achieved only by the largest tonnage in the model family and only with a specific indoor pairing. A Carrier Infinity 23 series advertised "up to 23 SEER2" might only hit that number in the 2-ton size with a premium air handler, while the 4-ton version with the same family's 4-ton indoor coil might be 19 SEER2.[7]Always ask for the AHRI certificate that matches the exact combination of outdoor unit, indoor unit, and tonnage being quoted.

COP at Minus 15 Celsius for Cold-Climate Heat Pumps

HSPF2 is useful but it averages across a full heating season. Ontario winters hit minus 15 Celsius (5 F) on multiple days every year. At that temperature a heat pump's heating capacity drops, its electricity draw rises, and its Coefficient of Performance (COP) falls well below the seasonal HSPF2 average. This is the temperature band where the difference between a budget heat pump and a true cold-climate model shows up on your bill.

COP is instantaneous, not seasonal. A COP of 2.0 at minus 15 means the unit delivers 2 BTUs of heat for every BTU of electricity it draws at that exact outdoor temperature. For context:

• An electric resistance baseboard heater: COP of exactly 1.0 at any temperature.
• A budget single-stage heat pump at minus 15 Celsius: roughly COP 1.4 to 1.6 (marginally better than resistance heat).
• A modern variable-speed cold-climate heat pump at minus 15 Celsius: COP 1.8 to 2.5 (Carrier Infinity 21 Cold Climate reports COP around 2.3, Mitsubishi Zuba-Central around 2.0 to 2.4).[7]
• Natural gas furnace at 96 percent AFUE: effective COP of 0.96 (gas is cheap per BTU, but the heat-per-unit-energy math still matters).

The ENERGY STAR Cold Climate floor is COP 1.75 at 5 F. The Ontario HRS floor is slightly stricter at COP 1.8 at minus 15 Celsius.[6]Both also require 70 percent capacity retention: if the unit produces 30,000 BTU/hour at 8.3 Celsius (47 F), it must still produce at least 21,000 BTU/hour at minus 15 Celsius. Without that, the unit will need auxiliary resistance heat or a backup fuel source to keep the house warm on the coldest days, which kills the efficiency advantage.

For more on which specific cold-climate models clear the Ontario bar and what auxiliary heat planning looks like, see our Cold Climate Heat Pump Ontario guide.

NEEP Cold-Climate Heat Pump Listing

The Northeast Energy Efficiency Partnerships (NEEP) maintains the cold climate air-source heat pump (ccASHP) product list at neep.org. A unit on the NEEP list has been independently verified to meet the cold-climate thresholds: COP of at least 1.75 at 5 F, at least 70 percent capacity retention at 5 F compared to 47 F, and a variable-speed or multi-stage compressor.[3]

Why Ontario contractors care: most major Canadian rebate programs reference NEEP directly or use NEEP-equivalent criteria. The Canada Greener Homes Initiative, the Oil to Heat Pump Affordability Program, and the Ontario Home Renovation Savings Program all depend on the NEEP listing (or the parallel NRCan product list, which usually tracks NEEP). A model that is not on NEEP is unlikely to be approved for rebate dollars, even if the marketing brochure says "cold climate rated."[1]

Before signing any heat pump contract in Ontario that assumes rebate money as part of the financing, do three checks:

1. Search for the exact outdoor + indoor combination on neep.org/heating-electrification/ccashp-specification-product-list.
2. Search the same combination on the NRCan Canada Greener Homes product list at natural-resources.canada.ca.
3. Ask the contractor for the AHRI certificate number. Cross-check it at ahridirectory.org to confirm SEER2, HSPF2, and heating capacity at 17 F match what the brochure claims.

Contractors who know what they are doing will have all three of these numbers on hand. Contractors who get defensive when you ask are waving a red flag.

Real 2026 Spec Sheet Examples

Sample premium cold-climate heat pump specs from the Ontario market in 2026, pulled from manufacturer technical data and AHRI certificates:

The Carrier and Lennox cold-climate models, the Mitsubishi Zuba, and the KeepRite Ion 23 all clear both the ENERGY STAR Cold Climate and Ontario HRS bars. The Carrier Comfort 27SCA5 and the Carrier Performance 25TPA7 are fine central-region units, but neither is a proper ccASHP for rebate purposes at the Ontario minus 15 Celsius threshold.[7]

What This Means for Your 2026 Ontario Quote

When you are looking at two contractor quotes, the efficiency comparison needs three numbers side by side:

• SEER2: matters more if you use a lot of AC. Ontario cooling seasons are short, so the payback on high-SEER2 units is long.
• HSPF2: matters a lot if the unit is a heat pump. Ontario heating seasons are long and expensive, so HSPF2 gains compound across the bill.
• COP at minus 15 Celsius (or 5 F): the single most important number for any Ontario heat pump. Anything below COP 1.75 at 5 F means the unit will lean on auxiliary resistance heat or a backup fuel source during every cold snap, which negates most of the efficiency advantage on exactly the days you need it most.

For furnace buyers, the parallel rating is AFUE (Annual Fuel Utilization Efficiency), which was not affected by the M1 change and still uses the same scale it always did. See our Best Furnace Brands Ontario 2026 guide for the AFUE breakdown and brand-by-brand comparison.

Related Guides

• Cold Climate Heat Pump Ontario
• Best Furnace Brands Ontario 2026
• Central Air Conditioner Cost Ontario 2026
• Canada Greener Homes and Ontario Rebates 2026

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