In California, a new split-system central air conditioner under 45,000 BTU/h (about 3.75 tons) must be rated at least 14.3 SEER2 and 11.7 EER2 (9.8 EER2 if rated 15.2 SEER2 or higher). Larger split ACs need 13.8 SEER2 and 11.2 EER2, and split heat pumps need 14.3 SEER2 and 7.5 HSPF2 under the national standard. The AC minimums are Southwest-region rules, applied by installation date, since January 1, 2023.
Fallbrook Heating & Air installs and replaces air conditioners and heat pumps across North County. If you've seen older "14 SEER" or "16 SEER" labels, those ratings came from the previous test method. Here's how the current numbers work and how to choose.
What are the SEER2 minimums in California?
California is in the Department of Energy's Southwest region. Since January 1, 2023, new split ACs under 45,000 BTU/h must meet 14.3 SEER2 and 11.7 EER2 (9.8 EER2 if rated 15.2 SEER2 or higher); split ACs of 45,000 BTU/h or more must meet 13.8 SEER2 and 11.2 EER2; and split heat pumps must meet the national minimum of 14.3 SEER2 and 7.5 HSPF2.
| Equipment | SEER2 | EER2 | HSPF2 |
|---|---|---|---|
| Split central AC, under 45,000 BTU/h | 14.3 | 11.7 (9.8 if rated 15.2+ SEER2) | n/a |
| Split central AC, 45,000 BTU/h and up | 13.8 | 11.2 (9.8 if rated 15.2+ SEER2) | n/a |
| Split heat pump | 14.3 | n/a (no regional EER2 minimum listed) | 7.5 |
Most single-family homes in North County use systems under 45,000 BTU/h, so for most households the number to remember is 14.3 SEER2. These are minimums: higher-rated equipment is widely available.
What do SEER2, EER2 and HSPF2 mean?
SEER2 is seasonal cooling efficiency, averaged across a range of outdoor temperatures. EER2 is cooling efficiency at one hot condition, a good guide to performance on peak afternoons. HSPF2 is a heat pump's seasonal heating efficiency. For all three, a higher number means more heating or cooling for each unit of electricity.
- SEER2 (Seasonal Energy Efficiency Ratio 2): the headline cooling number, best for comparing typical-year running cost.
- EER2 (Energy Efficiency Ratio 2): how efficient the AC is when it's hot outside. Matters most in inland heat.
- HSPF2 (Heating Seasonal Performance Factor 2): heat pump heating efficiency over a winter.
Why is SEER2 lower than the old SEER numbers?
The test changed, not the equipment. In 2023 the DOE moved to the "M1" test procedure, which uses higher external static pressure to better reflect real ductwork. Equipment tested this way scores lower than under the old method, so a SEER2 rating is a lower number than the same unit's old SEER rating.
That's why you should only compare SEER2 to SEER2. An old system labeled "14 SEER" isn't directly comparable to a new one rated 14.3 SEER2.
Does the rule apply to when the unit was made or when it's installed?
For split air conditioners in the Southwest region, the standard is tied to installation: equipment installed in California from January 1, 2023 must meet the regional SEER2 and EER2 minimums. A licensed contractor pulling a permit should only install compliant equipment. Ask to see the AHRI rating for your exact matched system.
The efficiency rating applies to the matched combination of outdoor unit and indoor coil (and, for some systems, the furnace or air handler). The same outdoor unit can carry different ratings with different coils, which is one reason a matched system matters.
What SEER2 rating should I choose?
Choose based on how hard your AC works. Inland homes in Fallbrook, Bonsall, Escondido and Temecula run the AC through long, hot summers, so higher efficiency has more hours to pay back on SDG&E rates. Coastal homes in Oceanside and Carlsbad cool far less, so the minimum is often the better value.
| Your situation | Usually makes sense | Why |
|---|---|---|
| Coastal home, light AC use | Minimum to modest step up | Fewer cooling hours means slow payback on premium efficiency |
| Inland home, heavy summer use | A step above minimum, with a good EER2 | Long run hours and hot afternoons reward efficiency |
| Hot or cold rooms, comfort complaints | Two-stage or variable-speed equipment | Longer, gentler cycles even out temperatures and humidity |
| Replacing both heating and cooling | Compare a heat pump (check HSPF2) | One system handles both; see our heat pump vs furnace guide |
Efficiency ratings only deliver if the installation is right: correct sizing, sealed ducts and the correct refrigerant charge. California's 2025 Energy Code requires duct sealing and third-party verification when you replace the outdoor unit, coil or air handler, and additional verification can apply depending on equipment and climate zone.
How do I check a system's SEER2 rating?
Ask your contractor for the AHRI certificate for the exact combination they're proposing: the outdoor unit, the indoor coil, and the furnace or air handler where it applies. AHRI, the industry certification body, publishes certified ratings for matched systems. The certificate lists SEER2, EER2 and, for heat pumps, HSPF2.
The yellow EnergyGuide label on an outdoor unit is a useful guide, but it describes a typical pairing, not necessarily yours. Compare quotes on the certified rating of the matched system, and check that each one meets the California minimums in the table above. If one quote's rating is much higher than another's for similar equipment, ask why.
What about heat pumps?
Split heat pumps installed in California must meet at least 14.3 SEER2 for cooling and 7.5 HSPF2 for heating. In our mild winters, HSPF2 matters less than it would in a cold climate, but a higher HSPF2 still lowers winter electricity use. Compare both numbers when choosing.
See our heat pump page and our heat pump vs furnace guide.
Does refrigerant affect the rating?
Not directly. New split systems manufactured from January 1, 2025 use A2L refrigerants such as R-454B or R-32, and they're rated under the same SEER2 rules. Pre-2025 R-410A equipment can still be installed after a May 2026 EPA rule, but it too must meet the regional minimums.
Read more in our R-410A phase-out guide, and see how efficiency fits into the budget in our AC replacement cost guide.
Frequently asked questions
What is the minimum SEER2 rating in California?
For a new split-system central air conditioner under 45,000 BTU/h, the minimum in California is 14.3 SEER2 and 11.7 EER2 (9.8 EER2 if rated 15.2 SEER2 or higher). Larger split ACs, 45,000 BTU/h and up, need 13.8 SEER2 and 11.2 EER2. Split heat pumps need 14.3 SEER2 and 7.5 HSPF2 nationwide. These federal standards took effect January 1, 2023.
What's the difference between SEER and SEER2?
SEER2 is the updated test method the Department of Energy adopted in 2023. It tests equipment under conditions closer to real homes, including more realistic duct resistance, so SEER2 numbers come out lower than old SEER numbers for the same unit. Compare SEER2 to SEER2, never to an old SEER rating.
Why does California have an EER2 requirement?
EER2 measures efficiency at a single hot condition, so it reflects how a system performs on the hottest afternoons. California is in the federal Southwest region, where summer peaks are a big part of cooling demand, so split ACs here must meet an EER2 minimum as well as a SEER2 minimum.
Is a higher SEER2 rating worth it?
It depends on how hard your AC works. In hot inland areas like Fallbrook, Escondido and Temecula, where the AC runs long hours, higher efficiency has more time to pay back. Near the coast, where AC use is lighter, a minimum-efficiency system is often the better value. We'll show you options at different levels.