The central AC efficiency rating California homeowners will see on a new unit is SEER2, with EER2 beside it. Federal rules set a minimum for both, and the minimum for air conditioners is higher in California than in most states. The figures below come from the federal regulation, checked on October 13, 2026.
What Is the Minimum Efficiency Rating for a Central AC in California?
A split-system central air conditioner installed in California must have a SEER2 of at least 14.3 if its cooling capacity is under 45,000 Btu per hour. The federal rule was checked on October 13, 2026.
The rule is in the federal energy conservation standards, 10 CFR 430.32. It puts California in a region it calls the Southwest, with Arizona, Nevada and New Mexico. The regional minimums apply to air conditioners installed on or after January 1, 2023.
| Air conditioner type | Minimum SEER2 in California | Minimum EER2 in California |
|---|---|---|
| Split system, under 45,000 Btu per hour | 14.3 | 11.7, or 9.8 if the SEER2 is 15.2 or higher |
| Split system, 45,000 Btu per hour or more | 13.8 | 11.2, or 9.8 if the SEER2 is 15.2 or higher |
| Single-package unit | 13.4 | 10.6 |
A split system has an outdoor unit and an indoor unit joined by refrigerant piping. A single-package unit has all its major parts in one cabinet.
What Do SEER2 and EER2 Mean?
SEER2 measures cooling efficiency over a whole cooling season. EER2 measures it at one fixed condition. A higher number means less electricity for the same cooling.
ENERGY STAR's heat pump criteria page defines both terms for heat pumps:
- SEER2, the seasonal energy efficiency ratio 2, is the heat removed from the home over the cooling season divided by the electricity used over the same season.
- EER2, the energy efficiency ratio 2, is the rate of cooling delivered divided by the rate of electricity used.
The federal rule adds that the regional EER standard is rated at an outdoor temperature of 95 °F.
How Is SEER2 Different From SEER?
They come from two test procedures. A rating measured under the federal procedure called Appendix M1 is a SEER2, and one measured under the older Appendix M is a SEER.
That is how the ENERGY STAR criteria page, linked above, separates them. So a SEER2 figure and a SEER figure aren't directly comparable. The federal rule uses SEER2 for equipment manufactured on or after January 1, 2023.
Is the California Minimum Higher Than the National One?
Yes, for split-system air conditioners. The national minimum is a SEER2 of 13.4, and the Southwest minimum is 14.3 or 13.8, depending on the unit's capacity.
Both figures are in the federal standards. The national minimums apply to equipment manufactured on or after January 1, 2023:
| Product | National minimum SEER2 | National minimum HSPF2 |
|---|---|---|
| Split-system air conditioner | 13.4 | Not applicable |
| Single-package air conditioner | 13.4 | Not applicable |
| Split-system heat pump | 14.3 | 7.5 |
| Single-package heat pump | 13.4 | 6.7 |
HSPF2 is a heating rating, so it applies only to heat pumps. The regional rule also says an outdoor unit can't be installed in a region if any of its certified combinations rates below that region's standard.
What Rating Does an ENERGY STAR Heat Pump Need?
A split-system heat pump needs a SEER2 of at least 15.2, an EER2 of at least 11.0 and an HSPF2 of at least 7.8 to earn the label.
Those levels are on the ENERGY STAR criteria page. A heat pump is rated for heating as well as cooling, which is why it carries an HSPF2. For single-package heat pumps the levels are a SEER2 of 15.2, an EER2 of 10.0 and an HSPF2 of 7.2.
Utility programs set their own requirements. The eligibility check and the rebate calculator show the verified programs for a specific address, and the PG&E programs page lists what DuloCore has verified for PG&E customers.
Frequently Asked Questions
What is a good SEER2 rating for an AC in California?
The federal rule sets a floor, not a recommendation. In California the floor for a split-system air conditioner is 14.3 or 13.8, depending on capacity.
Where do I find the rating of a unit in a quote?
Ask the contractor for the SEER2 and EER2 of the exact outdoor and indoor combination, in writing. The federal rule looks at the ratings of an outdoor unit's certified combinations.
Does the California minimum apply to heat pumps?
The regional rule covers air conditioners. Heat pumps follow the national minimums in the second table.
Replacing a central AC? See the verified rebates for your address with the free rebate calculator.