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SEER2, EER2, HSPF2: what the numbers mean
Three acronyms come up on every heat pump record. Two sum up a whole season; the third describes a single heat-wave afternoon. This guide says what each one measures, under what conditions, and why it carries a “2”, with the values of two 12,000 BTU wall units sold by AirGreen.
ORION XLTH · 12,000 BTU
ASUH12KZAS / AOUH12KZAH1 · AHRI 214888802
See the product page
EXTRÊME R32 · 12,000 BTU
GWH12AVDXE-D6DN***/I / GWH12AVDXE-D6DNA1B/O · AHRI 215386290
See the product pageWhat the electricity costs, in dollars, winter and summer
AirGreen estimate for the same 12,000 BTU/h zone in Montréal, at Hydro-Québec’s Rate D, taxes included. The two example heat pumps are calculated in exactly the same way, with the same method as on all our comparison pages; only their two seasonal ratings change, Region V HSPF2 and SEER2. Electric baseboards serve as the reference point.
How this amount is calculated
- Heat to deliver over the winter. A zone whose heat loss reaches 12,000 BTU/h ( kW) at −23.1 °C, Montréal’s design temperature: kW × 24 h × 4,167 degree-days ÷ (18 − (−23.1)) = kWh of heat for round-the-clock heating, all winter. Heating degree-days (base 18 °C) and design temperature: Natural Resources Canada, HOT2000 climate data, Montréal Intl station. With fewer hours per day (“Heating” slider), the heat is reduced in the same proportion, for the heat pump as for the baseboards: this simplification does not account for recovery after a temperature setback.
- Electricity for heating. Heat pump: heat × 3.412 ÷ HSPF2 Region V, the AHRI certificate value published by NEEP. Region V is the coldest in the standard, and its calculation includes the electric backup expected when the heat pump is no longer enough. Electric baseboards: 1 kWh of electricity for 1 kWh of heat.
- Electricity for cooling. 12,000 BTU/h ÷ SEER2 × hours per day × 60 days ÷ 1,000: the method of Hydro-Québec’s air-conditioning calculator, with the SEER2 seasonal efficiency from the AHRI certificate. The number of hours is a scenario you can set above, from 1 to 24 h. At 24 h, the calculation assumes rated capacity all day long: that is a ceiling, since a variable-speed unit slows down once the room is at temperature.
- Price. Hydro-Québec Rate D in effect April 1, 2026: 7.065¢ per kWh up to 40 kWh a day, 11.142¢ beyond; the average price, 9.104¢, is the one Hydro-Québec’s calculators use. GST and QST included. Network access charges, the same with or without a heat pump, are not counted.
AirGreen method v1.1, November 9, 2026. An estimate is used to compare units under the same conditions. The actual bill depends on the house, the insulation, the settings and the use; this amount is not a promise.
Two seasons and one afternoon
SEER2 covers the cooling season, HSPF2 the heating season, and EER2 a single point: 35 °C outdoors. Pick a rating: the ring shows the part of the year it sums up, and the chart, the temperatures the standard brings into the calculation.
The ring is a diagram. The DOE describes the heating season as the months that require heating, “typically, and roughly”, October through April. The cooling season is defined by outdoor temperatures, from 65 to 104 °F (18.3 to 40 °C), without dates: its arc is placed over summer as an illustration. The bars reproduce Tables 19 and 20 of Appendix M1 as the DOE published it on January 5, 2017; the current version refers to the corresponding tables of AHRI Standard 210/240-2024. In heating, the shares do not add up to 100%: Table 20 enters zero for the two mildest bins, those at 62 and 57 °F.
Each rating answers a different question
All three use the same unit, BTU per watt-hour. Divided by 3.412, a rating becomes a unitless ratio: kilowatt-hours of heat or cooling per kilowatt-hour of electricity.
SEER2How much electricity for a summer?
The heat removed from the home over the whole cooling season, in BTU, divided by the electricity used over that season, in watt-hours. The calculation weights eight temperature bins; the mildest weigh the most.
What it does not say: what the unit uses on a heat-wave day.
EER2And when it is 35 °C?
Cooling capacity, in BTU/h, divided by input power, in watts, at a single condition: 95 °F outdoors (35 °C), at full capacity. Divided by 3.412, EER2 gives back the rated COP the NEEP record shows at 35 °C.
What it does not say: efficiency at milder temperatures, where a variable-speed unit spends most of the summer.
HSPF2How much electricity for a winter?
The heat to deliver over the whole heating season, in BTU, divided by the electricity used, in watt-hours. The calculation also counts the electric backup that fills the gap when the heat pump is not enough. The rating changes with the climate region used.
What it does not say: the capacity left in deep cold. For that, read the NEEP record points at −15 °C and below.
A reading rule. Two ratings can be compared only when they carry the same name: SEER2 with SEER2, EER2 with EER2, HSPF2 with HSPF2 for the same region. A one-point SEER2 gap between two units says nothing about their gap in heating; the two examples on this page show it.
The “2” signals a different test procedure
SEER, EER and HSPF existed before. The “2” was added when the U.S. Department of Energy (DOE) replaced its test procedure, Appendix M, with Appendix M1. The DOE says so itself: the new ratings are based on the old ones, but their values are generally different.
The DOE publishes the final rule that creates Appendix M1 and the three new ratings.
In the United States, advertised efficiencies must be based on Appendix M1: SEER2, EER2 and HSPF2 replace the old ratings.
Representations must follow the amended Appendix M1, which refers to AHRI Standard 210/240-2024 for calculating the three ratings.
Among the points the DOE says it changed, three explain most of it for a buyer: the static pressure of ducted systems, the heating calculation and the treatment of variable-speed units.
A minimum pressure for ducts
Appendix M1 sets the minimum external static pressure of a conventional ducted system at 0.50 inch of water. A wall unit is not affected: a non-ducted unit is tested at zero external static pressure.
The heating load line, redrawn
The line that represents the reference house’s heating need was redone from an Oak Ridge National Laboratory study. In Region IV, this need starts below 55 °F rather than below 65 °F, with a slope factor of 1.15.
Variable speed has its own factors
For a variable-speed heat pump, the building cooling load is multiplied by 0.93 in the SEER2 calculation, and the heating slope factor is 7% lower: 1.07 rather than 1.15 in Region IV. Both examples on this page are variable-speed.
On our pages. A SEER and a SEER2 do not come from the same test. We therefore compare ratings of the same name and do not convert one into the other. When a manufacturer’s document still shows an old SEER, the page says so and uses the SEER2 value from the AHRI certificate.
What we are asked about these three ratings
What does a SEER2 of 30.5 mean?
Over the standard’s cooling season, the unit removes 30.5 BTU of heat for each watt-hour of electricity used. Divided by 3.412, that is 8.94 kWh of cooling per kWh of electricity. As a reference point, the Canadian federal minimum standard for the general category of split-system central heat pumps is a SEER2 of 14.3.
Can a SEER be converted into a SEER2?
Our pages do not. The DOE writes that the new ratings generally have different values from the old ones, and the gap depends on the type of unit. The NEEP specification gives equivalences for its own thresholds, for example an HSPF2 of 8.5 for a former HSPF of 10 for a non-ducted unit, but these are not conversion rules for a specific model.
Why does HSPF2 have two values on the NEEP record?
Because the calculation depends on the climate used. Region IV is used for compliance in the United States; Region V, colder, is the one Canadian federal regulations use for their minimum standard, an HSPF2 of at least 6.0 in the general category. For a given heat pump, Region V HSPF2 is lower: 10.1 versus 12.7 for the ORION XLTH, 8.0 versus 10.0 for the EXTRÊME R32.
What is EER2 for if SEER2 exists?
They do not look at the same moment. SEER2 averages a season dominated by mild hours. EER2 describes the unit at full capacity when it is 35 °C outdoors. In the standard’s reference season, 2.2% of cooling hours are at 35 °C or above.
Do these ratings tell me what I will pay?
No. They compare units over a reference season, the same for all. Your bill depends on the house, its insulation, the settings and the hours of use. The estimate at the top of the page shows the order of magnitude for a 12,000 BTU/h zone in Montréal, with its method.
Will these ratings change again?
The U.S. text in force announces it: Appendix M1 already names two upcoming ratings, SCORE for cooling and SHORE for heating, which will apply on the compliance date of future standards. Until then, records show SEER2, EER2 and HSPF2, and those are the three ratings our pages use.
Does HSPF2 account for deep cold?
In part. The Region IV calculation season goes down to the −8 °F bin (−22.2 °C) and Region V’s to −23 °F (−30.6 °C), but those hours are rare in the calculation. When the heat pump is not enough, the calculation adds electric backup. To know what a unit delivers at a specific temperature, read its NEEP record.
The three ratings of the two examples
Values read on NEEP records no. 392122 and no. 389444 on November 10, 2026. Nothing is highlighted: this guide explains the ratings; it does not rank the two units.
| Value | ORION XLTH | EXTRÊME R32 |
|---|---|---|
| Cooling | ||
| SEER2Cooling season | 30.5 | 29.5 |
| EER235 °C outdoors, full capacity | 16.0 | 15.2 |
| Rated COP at 35 °CNEEP record; equal to EER2 ÷ 3.412 | 4.69 | 4.45 |
| Rated capacity at 35 °C | 12,000 BTU/h | 12,000 BTU/h |
| Heating | ||
| HSPF2 Region IVDesign temperature: −15 °C | 12.7 | 10.0 |
| HSPF2 Region VDesign temperature: −23.3 °C | 10.1 | 8.0 |
| Rated capacity at 8.3 °C | 16,000 BTU/h | 12,200 BTU/h |
| Documents | ||
| AHRI certificate · NEEP record | 214888802 · 392122 | 215386290 · 389444 |
| ENERGY STAR cold climatePer the NEEP record | Yes | Yes |
| Refrigerant | R-32 | R-32 |
Bars on the same row share the same scale. They illustrate values measured under the same conditions; they are not a recommendation.
Both are on the AirGreen website.
To choose for your room, talk to our team: bring the room dimensions, the planned outdoor location and your current heating.
Where each number comes from
Data verified on November 10, 2026. This guide explains three efficiency ratings; it ranks neither units nor brands. The two heat pumps serve as examples and receive the same treatment. The DOE and AHRI texts are summarized: only those texts are authoritative.
Trademarks. FUJITSU AIRSTAGE, ORION XLTH, GREE, EXTRÊME, AHRI, NEEP and ENERGY STAR are trademarks of their respective owners. Logos are used only to identify the products shown. AirGreen is a dealer for both equipment brands; this page is not produced, sponsored or approved by the manufacturers, AHRI or NEEP.
Photos: AirGreen and manufacturers, for identification.
Does a value look wrong? Write to us: every reported value is verified again.