SEER2 Requirements by State: What a New AC Must Meet

A new central air conditioner must meet a federal efficiency minimum that depends on the state where it is installed: 13.4 SEER2 in the North, and 14.3 SEER2 in the Southeast and Southwest for split systems under 45,000 Btu/h (13.8 SEER2 for larger ones), with an added EER2 minimum in the Southwest. Split-system heat pumps have a single national floor of 14.3 SEER2 and 7.5 HSPF2. These U.S. Department of Energy (DOE) standards have applied since January 1, 2023, and they are still the ones in force in September 2026.

What SEER2, EER2 and HSPF2 measure

Each number describes a different kind of efficiency, and a higher number means less electricity for the same result. DOE defines them this way:

• SEER2 is seasonal: the heat removed from the house over a cooling season divided by the electricity used over that season.
• EER2 is peak: cooling delivered per watt at 95°F outdoors, when the system works hardest. DOE notes that EER is especially important in hot, dry climates.
• HSPF2 is the heating-season counterpart for heat pumps.

The “2” marks a revised DOE test procedure, adopted to better reflect how systems perform once installed in real homes. DOE says the new ratings are similar to the old SEER, EER and HSPF but not directly comparable. AHRI, the industry body that publishes the rating standards, gives the equivalents: 13.4 SEER2 corresponds to the old 14 SEER, 14.3 SEER2 to 15 SEER, and 13.8 SEER2 to 14.5 SEER.

The three regions

DOE split the country by climate. States with 5,000 or more population-weighted heating degree days form the North; the warmer states were then divided into a hot-humid Southeast and a hot-dry Southwest.

• Southeast: Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, Puerto Rico and the U.S. territories.
• Southwest: Arizona, California, Nevada and New Mexico.
• North: every other state.

The minimums, region by region

The table lists the federal floors in 10 CFR 430.32 that took effect on January 1, 2023. The next section explains when they apply by date of manufacture and when by date of installation.

Equipment	North	Southeast	Southwest
Split AC, under 45,000 Btu/h	13.4 SEER2	14.3 SEER2	14.3 SEER2 and 11.7 EER2
Split AC, 45,000 Btu/h and up	13.4 SEER2	13.8 SEER2	13.8 SEER2 and 11.2 EER2
Single-package AC	13.4 SEER2	13.4 SEER2	13.4 SEER2 and 10.6 EER2
Split heat pump	14.3 SEER2, 7.5 HSPF2	same	same
Single-package heat pump	13.4 SEER2, 6.7 HSPF2	same	same

In the Southwest, a split air conditioner rated 15.2 SEER2 or higher has a lower EER2 floor of 9.8.

The Southwest is the only region with a peak-efficiency requirement. EER2 is measured at 95°F, so the rule targets performance on the high-temperature days that DOE says are more common in hot-dry climates.

Installation date or manufacture date

In the North, the rule follows the date of manufacture. DOE’s guidance says units made before January 1, 2023 that met the earlier standards may still be installed there.

In the Southeast and Southwest, the regional rule follows the date of installation. It covers split air conditioners in both regions, and single-package air conditioners in the Southwest as well. DOE puts it plainly: it is illegal for a contractor to install a product that does not meet the regional standard in those regions. Federal rules define installation as connecting the refrigerant lines or electrical system to make the air conditioner operational.

DOE’s Office of the General Counsel takes reports of suspected illegal installations; its regional standards enforcement page gives the contact.

The rating belongs to a combination

Federal rules treat a split system’s efficiency as a property of a certified combination: an outdoor unit together with a specific indoor coil or air handler. For the Southeast and Southwest, 10 CFR 430.32 states that an outdoor unit model with any certified combination rated below the regional standard cannot be installed in that region.

That is why the practical check is a certificate, not a sticker. ENERGY STAR’s design report for new homes asks for the AHRI reference number that represents the rated efficiency of the specific combination of indoor and outdoor components. The Federal Trade Commission’s Energy Labeling Rule also requires manufacturers to make the EnergyGuide label for each central air conditioner and heat pump model available on a publicly accessible website (16 CFR 305.22).

Above the minimum: ENERGY STAR

ENERGY STAR sets a higher bar. Its current specification, Version 6.2 (revised March 2025), requires:

• Split central air conditioners: at least 15.2 SEER2 and 12.0 EER2.
• Single-package air conditioners: at least 15.2 SEER2 and 11.5 EER2.
• Split heat pumps: at least 15.2 SEER2, 11.0 EER2 and 7.8 HSPF2.
• Cold-climate split heat pumps: at least 8.1 HSPF2 for ducted systems and 8.5 for ductless ones, plus tested performance at 5°F.

Whether the extra efficiency pays back in a given house depends on local climate and electricity rates, which is a calculation to ask a contractor to show, not assume.

SEER2 and the federal tax credit

SEER2 used to matter for a federal tax credit, and that credit has ended. The Internal Revenue Service states that the Energy Efficient Home Improvement Credit, section 25C, “will not be allowed for any property placed in service after December 31, 2025.”

While it existed, the credit used its own efficiency test: the IRS required central air conditioners to meet the highest efficiency tier set by the Consortium for Energy Efficiency, not counting any advanced tier, in effect at the start of the year of installation. For equipment placed in service in 2026, there is no federal credit to qualify for, whatever its SEER2.

What comes after SEER2

The names may change again, but not yet. A DOE final rule published January 7, 2025 adopted a future test procedure, called appendix M2, with two new metrics: SCORE for cooling and SHORE for heating. DOE states that testing to SCORE and SHORE will not be required until compliance is required with new efficiency standards based on them.

As of September 29, 2026, no such standards are in force, and the federal minimums for current equipment are stated in SEER2, EER2 and HSPF2.

When a professional is needed, and what to ask

Replacing a central air conditioner or heat pump is contractor work, and the efficiency rules above are what to check on the written proposal before anything is signed.

Questions worth asking:

• What is the AHRI reference number for the exact outdoor unit and indoor coil or air handler you propose, and what SEER2, EER2 and HSPF2 does that certificate show?
• In the Southeast or Southwest: does that combination meet the regional standard for this state?
• Is the size based on a load calculation for this house? A different size can change which combination, and which rating, applies.
• Where can I see the EnergyGuide label for these models?
• Does the proposed system qualify for ENERGY STAR under Version 6.2? If not, which higher-efficiency option would you suggest for this climate, and why?