The DOE regional standards are the part of the federal efficiency rules that sets different minimum air-conditioner efficiencies for different parts of the country. The U.S. Department of Energy administers them under the Energy Policy and Conservation Act at 10 CFR Part 430. The framework divides the United States into three regions — North, Southeast, and Southwest — and assigns each a different minimum for residential central air conditioners, on the logic that cooling efficiency matters more where the cooling season is longer and hotter. The current SEER2 minimums took effect January 1, 2023, building on the regional structure that has applied since January 1, 2015.
The regions are defined by state. The Southwest is Arizona, California, Nevada, and New Mexico; the Southeast covers Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, and the U.S. territories; the North is the remainder. A new split-system air conditioner must meet 13.4 SEER2 in the North and 14.3 SEER2 in the Southeast and Southwest for units under 45,000 BTU per hour. The Southeast standard applies to split-system air conditioners, while the Southwest standard covers both split and single-package air conditioners and adds a full-load EER2 minimum for hot-dry operation. Heat pumps are regulated nationally, not regionally, at 14.3 SEER2 and 7.5 HSPF2.
A subtle but important part of the rule is how it is enforced, which differs by region. In the North, compliance is based on the date of manufacture, so units built before a standard's effective date can still be sold and installed under a sell-through period. In the Southeast and Southwest, compliance is based on the date of installation, meaning a unit that does not meet the regional minimum cannot be legally installed there even if it was manufactured earlier — there is no sell-through. That is why a central air conditioner that is perfectly legal to install in a northern state may not be installable in Arizona or Texas. The standards are current as of 2026; they did not change when the federal tax credits expired at the end of 2025 or as the R-454B refrigerant transition took effect.
For a 2026 buyer, the regional rule mostly operates in the background, but it has two practical consequences. First, in the Southeast and Southwest — which include all of Texas and Arizona — the installed unit must meet the regional minimum on the day it goes in, so a contractor cannot install leftover lower-efficiency stock to save money. Second, the regional floor is still just a floor: utility rebates in these states require efficiency well above 14.3 SEER2, so meeting the regional minimum does not earn a rebate. When comparing quotes, check that the proposed unit clears both the regional minimum and the specific rebate tier, using the SEER2 figure on the AHRI certificate.