What Is a Good SEER Rating in 2026? SEER2 Minimums vs ENERGY STAR

SEER2 ratings at a glance

Sources: 10 CFR 430.32(c)(5)–(6); ENERGY STAR.

In the Southwest, split ACs under 45,000 Btu/h also need 11.7 EER2 if rated below 15.2 SEER2, or 9.8 EER2 if rated at 15.2 SEER2 or higher. Units 45,000 Btu/h and up need 11.2 or 9.8 EER2 on the same split. The regulation defines the Southeast as Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, Puerto Rico, South Carolina, Tennessee, Texas, Virginia, D.C. and the U.S. territories, and the Southwest as Arizona, California, Nevada and New Mexico. Everywhere else uses the national minimums.

What SEER2, EER2 and HSPF2 mean

ENERGY STAR defines them, based on DOE's test procedure (ENERGY STAR):

• SEER2: total heat removed over a cooling season, in Btu, divided by the electricity used, in watt-hours. Higher is more efficient over a season.
• EER2: cooling delivered divided by electricity used at a single set of conditions. The federal rule rates it at 95 °F outdoors, which is why it matters in very hot climates.
• HSPF2: the heating-season version for heat pumps.

The "2" means the rating comes from DOE's newer test procedure, Appendix M1. Older SEER, EER and HSPF ratings came from Appendix M. Because the tests differ, compare SEER2 numbers only with other SEER2 numbers.

How to decide how high to go

A higher SEER2 rating saves more when the AC runs more. An ENERGY STAR fact sheet on air conditioners, published in 2000, notes that air conditioning accounts for 15 percent of home energy use on average and over 40 percent in hot, humid regions (EPA ENERGY STAR). In a mild climate with a short cooling season, the minimum or ENERGY STAR level is often enough. In a long, hot cooling season, a higher rating has more hours to pay back its higher price.

Compare quotes on the same basis:

1. Get the matched-system rating. The rating applies to the specific outdoor and indoor combination. The federal rule says an outdoor unit with any certified combination rated below the regional standard cannot be installed in that region.
2. Check the EnergyGuide label. ENERGY STAR requires that the SEER2 and HSPF2 it lists match what was reported to DOE and shown on the FTC EnergyGuide label.
3. Check EER2 if you live somewhere very hot. It reflects performance at 95 °F.
4. Size it correctly first. An oversized high-SEER2 unit short-cycles and won't deliver its rated efficiency. Our guide to sizing a central air unit with a Manual J load calculation covers that step.

Do the math for your own house

Because SEER2 is Btu of cooling per watt-hour of electricity (ENERGY STAR), you can estimate the difference between two units with simple division. Take your seasonal cooling load in Btu, divide by the SEER2, and divide by 1,000 to get kilowatt-hours.

The table uses an example load of 30 million Btu per season. That number is for illustration only; your load depends on climate, house size and insulation.

Multiply the difference by the rate on your electric bill to get dollars per year. Then compare that with the price gap between the two quotes. The step from 13.4 to 15.2 saves more per SEER2 point than the step from 15.2 to 18, because each extra point divides into a smaller number. That is why the gains shrink as ratings climb.

A heat pump also heats, so for one, run the same comparison for heating with HSPF2 and your heating load.

Look up the exact combination

Ask each contractor for the model numbers of the outdoor unit, the indoor coil or air handler, and the furnace if there is one. The federal rule ties the rating to that certified combination (10 CFR 430.32). The AHRI Directory of Certified Product Performance lets you search those model numbers and see the certified SEER2, EER2 and HSPF2 for the match (AHRI Directory). If a quote lists only the outdoor unit, the efficiency on it may not be the one you get.

Federal tax credit: ended for 2026 installs

Until the end of 2025, some high-efficiency central air conditioners and heat pumps qualified for the section 25C energy efficient home improvement credit. The One, Big, Beautiful Bill ended it early. The IRS says the credit will not be allowed for any property placed in service after December 31, 2025 (IRS). A system installed in 2026 gets no 25C credit, so leave it out of your payback math. Check with your utility and state energy office for any local rebates instead.

Don't skip installation quality

A rating is measured in a lab with the system installed and charged as designed. Refrigerant charge, airflow and duct leakage in your home affect what you actually get. ENERGY STAR's maintenance checklist notes that too much or too little refrigerant makes a system less efficient, and that airflow problems can reduce efficiency by up to 15 percent (ENERGY STAR).