Minimum SEER Rating by State in 2026 (SEER2 Requirements Map)

If you're replacing or installing a central AC or heat pump, there's a federal efficiency minimum you have to meet, and it depends on which region of the country you're in. Buy a unit below your region's minimum and a reputable contractor won't install it, you'll fail inspection, and you'll be locked out of rebates and tax credits. So it's worth knowing the number before you shop.

This guide gives you the current SEER2 minimums by region and state, plus the details that trip people up (heat pumps, packaged units, and larger systems have their own rules). The standards come from the U.S. Department of Energy, and we link the federal regulation at the bottom.

The U.S. is divided into three DOE efficiency regions, and your state's minimum SEER2 depends on which one you're in. For split-system central air conditioners, the North requires 13.4 SEER2 and the South and Southwest require 14.3 SEER2. Split-system heat pumps have a single national minimum of 14.3 SEER2 and 7.5 HSPF2 in all regions.

Find your state below for its requirement.

Quick summary: the minimums

Two things to note right away: heat pumps are the same nationwide (14.3 SEER2 / 7.5 HSPF2, in every region, unlike ACs which vary by region), and larger ACs (45,000 BTU and up) in the South and Southwest have a slightly lower SEER2 floor (13.8) than smaller ones, because of how bigger systems are engineered. The Southwest also has EER2 requirements (a peak-efficiency measure) on top of SEER2.

The three regions, and which states are in each

North region (13.4 SEER2 for split ACs)

The North has milder, shorter cooling seasons, so its AC minimum is lower. These states require 13.4 SEER2 for split-system central ACs (heat pumps are 14.3 SEER2 / 7.5 HSPF2, the national figure):

Alaska, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Washington, West Virginia, Wisconsin, and Wyoming.

South region (14.3 SEER2 for split ACs)

The South has longer, hotter cooling seasons, so its AC minimum is higher. These states require 14.3 SEER2 for split-system central ACs under 45,000 BTU (13.8 SEER2 for larger units; heat pumps are 14.3 SEER2 / 7.5 HSPF2):

Alabama, Arkansas, Delaware, District of Columbia, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia.

Southwest region (14.3 SEER2 for split ACs, plus EER2 rules)

The hot, dry Southwest matches the South's SEER2 AC minimum but adds EER2 (peak-heat efficiency) requirements. These states require 14.3 SEER2 for split-system central ACs under 45,000 BTU (13.8 SEER2 for larger units), plus EER2 minimums, with heat pumps at the national 14.3 SEER2 / 7.5 HSPF2:

Arizona, California, Nevada, and New Mexico.

How these compare to old SEER numbers

If you're comparing to older equipment rated in the original SEER, the SEER2 numbers look lower, but they represent the same or higher real-world efficiency, because the SEER2 test (the M1 procedure) uses tougher, more realistic conditions:

The key point: even though 13.4 SEER2 looks close to the old 13 SEER minimum, it actually corresponds to about 14 SEER in the old terms. The DOE raised the real efficiency bar while changing the metric.

The details that catch people

Heat pumps are national, not regional. This is the most common point of confusion.

Unlike ACs, which have region-specific minimums, all split-system heat pumps must meet 14.3 SEER2 and 7.5 HSPF2 everywhere in the country. HSPF2 (the heating-efficiency measure) matters here: a heat pump that clears the SEER2 cooling requirement can still fail on HSPF2, so check both numbers.

Larger systems have their own floor. In the South and Southwest, split ACs of 45,000 BTU and up need 13.8 SEER2 rather than 14.3, reflecting the engineering of bigger units.

Packaged units are lower and uniform. Single-packaged systems (compressor and air handler in one outdoor unit) have a uniform 13.4 SEER2 minimum nationwide, lower than split systems because of their different design constraints.

Some states require more than the federal minimum. California, through its Title 24 building code, sometimes requires efficiency above the federal floor. Always check with your state energy office and local building department for requirements beyond the federal minimum.

Small-duct high-velocity systems (like Unico and SpacePak) have separate, lower efficiency minimums because their design creates inherently higher static pressure.

What happens if you install below the minimum

Installing a system that doesn't meet your region's minimum can cause real problems:

• Building inspectors can fail the installation and require replacement
• Manufacturer warranties may be voided
• You become ineligible for utility rebates, federal tax credits, and state incentives
• Your contractor can face fines and licensing issues

A practical warning: some online retailers sell equipment without checking regional compliance. If you buy, say, a 13.4 SEER2 unit online and live in the South (which requires 14.3 for split ACs), no reputable contractor will install it. Confirm your region's requirement before you buy.

Note that these minimums apply only to new installations. Your existing system can keep running regardless of its rating, you only have to meet the current minimum when you replace it.

How this affects a replacement

If you're replacing an aging system, any 2026 replacement will be more efficient, though how much more depends on what you have now:

• Replacing a pre-2006 unit (around 10 SEER): the jump to today's minimum is large, expect a meaningful efficiency gain.
• Replacing a 2006 to 2014 unit (around 13 SEER): a modest efficiency improvement, plus newer technology and a fresh warranty.
• Replacing a 2015 to 2022 unit (around 14 SEER): similar or slightly better efficiency at the code minimum, though you can choose a higher-SEER2 unit for more savings.

In every case you also get current refrigerant, newer technology, and a full manufacturer warranty. For choosing a rating above the minimum, see our good SEER rating guide, and for what SEER2 means, our SEER2 explained guide.

Frequently asked questions

Do I have to replace my AC if it's below the current minimum? No. Federal minimums apply only to new installations. Your existing equipment can keep operating regardless of its SEER rating. When you eventually replace it, the new system has to meet the current minimum for your region.

What's the minimum SEER2 for a heat pump? 14.3 SEER2 and 7.5 HSPF2, nationally, in every region. Unlike central ACs, heat pumps do not have region-specific minimums, the same standard applies whether you're in Maine or Florida. Check both the SEER2 (cooling) and HSPF2 (heating) numbers, since a unit can pass one and fail the other.

Which minimum applies if I live near a regional border? The state where the equipment is installed determines the requirement, regardless of how close you are to a boundary. For example, Virginia (South, 14.3 SEER2 for split ACs) borders West Virginia (North, 13.4 SEER2). Your state sets the rule.

Why are the SEER2 numbers lower than the old SEER numbers? Because the SEER2 test (the M1 procedure introduced in 2023) uses tougher, more realistic conditions, higher external static pressure, so the same equipment scores a bit lower under SEER2 than under the old SEER. A 13.4 SEER2 unit is roughly equivalent to a 14.0 SEER unit under the old test.

Is it illegal to install a unit below the minimum? Installing new equipment below your region's federal minimum violates DOE standards. In practice, reputable contractors won't do it, inspections can fail, warranties can be voided, and you lose eligibility for rebates and tax credits. It applies to new installations, not to equipment you already own.

About these figures

The regional SEER2, EER2, and HSPF2 minimums are set by the U.S. Department of Energy under its appliance energy conservation standards, codified in federal regulation (10 CFR Part 430). The three-region structure (North, South, Southwest), the split-AC minimums (13.4 SEER2 North; 14.3 SEER2 South and Southwest, dropping to 13.8 for units 45,000 BTU and larger), the national split-heat-pump minimum (14.3 SEER2 / 7.5 HSPF2 in all regions), and the packaged-unit minimum (13.4 SEER2) all follow the DOE standard that took effect January 1, 2023.

Equipment certification data is available through AHRI. State-level requirements above the federal minimum (such as California's Title 24) are set by individual states, confirm your local requirements with your state energy office and building department.

Related Articles

EER Chart for Air Conditioners (Good, Average, Excellent)

reference • 5 min read

HSPF and HSPF2 Explained: Heat Pump Heating Efficiency (2026)

explainer • 6 min read

MERV Rating Chart: What MERV Filter Do You Need?

reference • 9 min read

SEER2 to SEER Conversion: Chart and Formula (2026)

explainer • 6 min read