SEER2 and HSPF2 Ratings Explained: Which Numbers You Actually Need

Quick answer

SEER2 rates a heat pump’s cooling efficiency over a season; HSPF2 rates its heating efficiency over a season. Higher is better for both. New split-system heat pumps must be at least 14.3 SEER2 and 7.5 HSPF2. ENERGY STAR heat pumps start at 15.2 SEER2 and 7.8 HSPF2, and cold-climate certified models reach 8.1–8.5+ HSPF2. For most homes, a heat pump around 16–20 SEER2 and 8.5–9.5+ HSPF2 is the sweet spot. In cold climates, the heat pump’s capacity and efficiency at 5°F matter even more than HSPF2.

What each rating means

Rating	Measures	How it’s calculated	Higher means
SEER2 (Seasonal Energy Efficiency Ratio 2)	Cooling over a typical cooling season	Total cooling delivered (BTU) ÷ electricity used (watt-hours)	Lower summer bills
EER2 (Energy Efficiency Ratio 2)	Cooling at one hot condition (95°F outdoors)	Same ratio, at peak heat	Better efficiency on the hottest days; matters most in hot, dry climates
HSPF2 (Heating Seasonal Performance Factor 2)	Heating over a typical heating season	Total heat delivered (BTU) ÷ electricity used (watt-hours)	Lower winter bills
COP (Coefficient of Performance)	Heating efficiency at one temperature	Heat out ÷ electricity in, same units	3.0 means 3 units of heat per unit of electricity

A quick way to read HSPF2: divide it by 3.412 to get an approximate seasonal COP. An 8.5 HSPF2 heat pump delivers roughly 2.5 units of heat for every unit of electricity across a typical season, about 2.5 times as efficient as electric baseboard heat.

SEER vs SEER2: what changed in 2023

On January 1, 2023, the Department of Energy switched to a new test procedure (called M1) for central air conditioners and heat pumps. The new test uses higher external static pressure to better reflect how equipment performs with real-world ductwork. Same equipment, tougher test, so the numbers come out lower:

SEER2 is roughly 5% lower than the old SEER for the same unit.
HSPF2 is roughly 15% lower than the old HSPF.

Nothing got less efficient; only the yardstick changed. A unit rated 16 SEER under the old test is about 15.2 SEER2 under the new one (Energy Trust of Oregon).

Quick conversion table

Old SEER	≈ SEER2	Old HSPF	≈ HSPF2
14	13.4	8.2	7.0
15	14.3	8.8	7.5
16	15.2	9.5	8.1
18	17.1	10.0	8.5
20	19.0	11.0	9.4
22	20.9	12.0	10.2

Conversions are approximate; manufacturers publish exact SEER2 and HSPF2 values for each tested combination of indoor and outdoor units. Use those, especially when comparing quotes or checking rebate eligibility.

Watch out for mixed ratings. Some older listings, used equipment and overseas-made mini splits still quote SEER or HSPF. Don’t compare a SEER number from one quote with a SEER2 number from another; the SEER figure will look about 5% better than it really is.

What’s a good SEER2 and HSPF2? Benchmarks

Level	SEER2	HSPF2	Notes
Federal minimum, split-system heat pump (nationwide)	14.3	7.5	The lowest a new split heat pump can be (ACHR News)
Federal minimum, packaged heat pump	13.4	6.7	Single-cabinet units
ENERGY STAR, split-system heat pump	≥15.2	≥7.8	Also requires EER2 ≥11.0 under the current spec
ENERGY STAR Cold Climate, ducted	≥15.2	≥8.1	Plus COP ≥1.75 and ≥70% capacity at 5°F
ENERGY STAR Cold Climate, ductless	≥15.2	≥8.5	Same cold-temperature tests
Typical mid-range variable-speed	~17–20	~8.5–9.5	Common sweet spot for value
Top-tier ductless mini splits	~22–28+	~9.5–11+	Highest efficiency, highest price

ENERGY STAR criteria are from its current central AC and heat pump specification (ENERGY STAR; ENERGY STAR Cold Climate). One notable change: ENERGY STAR removed central air conditioners from its label effective February 1, 2026, so only heat pumps now carry the ENERGY STAR label in this category.

For air conditioners only, federal minimums still vary by region: 13.4 SEER2 in the North; 14.3 SEER2 in the Southeast and Southwest for units under 45,000 BTU/h (13.8 above that), plus EER2 minimums in the Southwest. Heat pump minimums are the same nationwide.

Our rule of thumb

Your situation	Aim for
Mild climate, tight budget	15.2+ SEER2, 7.8+ HSPF2 (ENERGY STAR)
Hot climate, high cooling bills	17–20+ SEER2; check EER2 for very hot, dry areas
Mixed climate, year-round use	16–20 SEER2, 8.5–9.5 HSPF2
Cold climate	ENERGY STAR Cold Climate or NEEP-listed, 8.5+ HSPF2, and strong 5°F capacity
Rebates in your area	Whatever tier your rebate program requires; it often pays for the upgrade

Is a higher rating worth paying for?

Energy use scales inversely with the rating: going from 14.3 to 18 SEER2 cuts cooling electricity by about 21% (1 − 14.3/18), and going from 7.5 to 9.5 HSPF2 cuts heating electricity by about 21% (1 − 7.5/9.5).

What that’s worth in dollars

Illustrative 2,000 sq ft home at 18¢/kWh, compared with a minimum-efficiency (14.3 SEER2 / 7.5 HSPF2) heat pump.

Cooling savings per year

Upgrade to	Mixed climate	Hot climate (e.g., Texas, Florida)
16 SEER2	~$60	~$150
18 SEER2	~$115	~$290
20 SEER2	~$160	~$405

Heating savings per year (about 50 million BTU of heat a year, a moderate-to-cold climate)

Upgrade to	Savings
8.5 HSPF2	~$140
9.5 HSPF2	~$255
10.5 HSPF2	~$345

Payback

Moving from a basic single-stage unit to a variable-speed unit around 18 SEER2 / 9.5 HSPF2 typically costs $2,000–$4,000 more installed.

Mixed climate: ~$370/year in combined savings → payback around 5–11 years, within the equipment’s 12–15 year life.
Hot climate with little heating: ~$340/year, mostly from cooling → similar payback.
Mild climate with low bills: savings may be under $150/year → the premium may not pay back on energy alone.

The math gets better when rebates require the higher tier (many do), when your electricity is expensive, or when you value the quieter, more even comfort of variable-speed equipment. It gets worse in mild climates with small bills.

Diminishing returns: each step up saves less than the one before. Going from 14.3 to 18 SEER2 saves far more than going from 22 to 26. Beyond about 20 SEER2, you’re mostly paying for comfort and quiet, not savings.

In a cold climate, look past HSPF2

HSPF2 is measured over a modeled heating season. Spec sheets often show two values:

HSPF2 Region IV: the standard rating, based on a moderate climate (roughly the middle of the US). This is the number usually advertised.
HSPF2 Region V: based on a colder climate. It’s typically lower, for example 10.2 in Region IV but 7.6 in Region V for the same unit, and it’s more realistic if you live in the North.

Even Region V doesn’t tell you how a heat pump behaves on your coldest nights. For that, check:

Spec	What it tells you	Good benchmark
Heating capacity at 5°F (BTU/h)	How much heat it actually makes in deep cold	Compare with your home’s heat loss at design temperature
Capacity ratio (5°F ÷ 47°F)	How much output it keeps as it gets cold	≥70% (ENERGY STAR Cold Climate); 90–100% for the best models
COP at 5°F	Efficiency in deep cold	≥1.75 (ENERGY STAR Cold Climate); 2.0+ is excellent
Minimum operating temperature	The point where the compressor stops	-13°F to -22°F for strong cold-climate models

The NEEP Cold Climate Air Source Heat Pump list publishes these values for thousands of models, and many northern rebate programs require a listed unit.

How to read a heat pump spec sheet or quote

Find the AHRI certificate number. Ratings apply to a specific matched combination of outdoor unit, indoor unit (or coil) and sometimes furnace. Ask for the AHRI certificate, and check it in the AHRI Directory.
Confirm the ratings are SEER2 / HSPF2 / EER2, not old SEER / HSPF.
Note which HSPF2 region is quoted, especially if you’re in a cold state.
For cold climates, find the 5°F capacity and COP (on the spec sheet, the extended performance table, or the NEEP listing).
Check the tier your rebate requires, such as ENERGY STAR, ENERGY STAR Cold Climate or a minimum SEER2/HSPF2, before you sign.
Compare like with like: same size, same rating basis, same indoor unit type.

Frequently asked questions

What is a good SEER2 rating for a heat pump?

15.2 SEER2 meets ENERGY STAR; 16–20 SEER2 is a strong, cost-effective range for most homes. Above about 20, savings shrink relative to the extra cost.

What is a good HSPF2 rating?

7.8 meets ENERGY STAR for split heat pumps; 8.5–9.5 is a good target for most homes; 8.1 (ducted) or 8.5 (ductless) is the floor for ENERGY STAR Cold Climate models.

What is 16 SEER in SEER2?

About 15.2 SEER2. SEER2 values are roughly 5% lower than old SEER values for the same equipment.

What’s the difference between SEER2 and EER2?

SEER2 measures cooling efficiency across a whole season; EER2 measures it at one hot condition (95°F). EER2 matters most in very hot, dry climates.

Is HSPF2 the same as COP?

No, but they’re related. HSPF2 is a seasonal value in BTU per watt-hour; dividing it by about 3.41 gives a rough seasonal COP. COP is usually quoted at a single temperature, such as 47°F or 5°F.

Do higher SEER2 heat pumps cost more?

Yes. Moving from a basic single-stage unit to a variable-speed unit near 18 SEER2 usually adds $2,000–$4,000, which typically pays back over 5–11 years in mixed climates.

Related guides

What Size Heat Pump Do I Need? Sizing by Square Footage and Climate Zone
Single-Stage vs Two-Stage vs Variable-Speed Heat Pumps
Do Heat Pumps Work Below 0°F? Data From Cold-Climate Models
The NEEP Cold-Climate Heat Pump List Explained for Homeowners
How to Compare Heat Pump Quotes: A Line-by-Line Checklist
Heat Pump Installation Cost in 2026: Real Prices by Home Size and System Type

Savings estimates are illustrative, using 18¢/kWh and typical loads. Federal and ENERGY STAR criteria can change; check the current requirements and your equipment’s AHRI certificate.