SEER2 is the number every listing leads with, and it is the one most people overpay for. Higher is better. But what higher is worth depends almost entirely on how many hours a year your system runs, and that is set by your climate, not by the brochure.
Here is what the number means, what the law requires where you live, and how to decide how far past the minimum is worth going.
What SEER2 measures
Seasonal cooling delivered divided by the electricity used to deliver it, under the test procedure that replaced SEER in 2023. The new test applies more realistic duct pressure, so a SEER2 figure reads a little lower than the old SEER for the same equipment: 14.3 SEER2 is roughly what used to be called 15 SEER. Always compare SEER2 with SEER2.
It is also a rating of the pair — condenser plus air handler — not of the condenser alone. Split the pair and the number no longer applies. Why an AHRI-matched system matters covers that.
The legal minimum depends on your region
Since 1 January 2023 the Department of Energy has set minimums for new central air conditioners by region:
North — 13.4 SEER2.
Southeast (Florida, Georgia, Alabama, Mississippi, Louisiana, Texas, Oklahoma, Arkansas, Tennessee, North and South Carolina, Virginia, Kentucky, Maryland, Delaware, DC) — 14.3 SEER2 for systems under 45,000 BTU, 13.8 SEER2 above that.
Southwest (Arizona, California, Nevada, New Mexico) — the same SEER2 floor as the Southeast, plus a minimum EER2 for performance in extreme heat.
Heat pumps — 14.3 SEER2 and 7.5 HSPF2 everywhere in the country.
Everything we sell meets the Southeast minimum, so any system on this site is legal to install anywhere in the continental US. The only question is how far above the floor to go.
Why climate changes the answer
A higher SEER2 saves a fixed share of your cooling electricity. What that share is worth depends on how much cooling electricity you buy. A house in Fort Myers runs its system most of the year. A house in Ohio runs it for a summer. The identical upgrade is worth three to four times more in Florida than in the North.
A rough illustration for a 3-ton system, stepping from 14.3 to 16 SEER2, at 15 cents per kWh: in South Florida, at around 2,500 hours of cooling a year, the step saves roughly $100 a year. In the North, at around 900 hours, the same step saves roughly $35. Over a 15-year life that is the difference between an upgrade that pays for itself twice over and one that barely pays for itself at all. Put your own numbers into the SEER2 savings calculator — it uses your electricity rate and your system size.
Our honest read, by situation
Florida, the Gulf Coast, Texas, Arizona. The upper tier is worth it. Stepping to 15.2 or 16 SEER2 pays back well inside the life of the equipment, and the better compressor and coil that come with it matter in a climate that runs them hard. Trane 5TTR6 at 16 SEER2, or RunTru A5AC5 at 15.2 SEER2.
The mid-South and mid-Atlantic. Either tier is a sound buy. 15.2 SEER2 is the sweet spot if you plan to stay in the house; 14.3 is the right call if you don't.
The North. 14.3 SEER2 is the sensible cooling buy — RunTru A5AC4, Trane 5TTR4 or Everwell CAC-15. If you are going heat pump, spend the money on the heating rating, HSPF2, which is the number you will actually live with.
A rental, or a house you'll sell within a few years. Minimum-compliant equipment from a brand with a real parts warranty. The next owner gets a new system; you don't pay for efficiency you won't be there to use.
Things that matter more than the last SEER2 point
Correct sizing. An oversized system short-cycles and never reaches the efficiency on its label. Get a Manual J load calculation from a contractor who has seen the property. We don't size systems remotely, on purpose.
The install. Refrigerant charge, airflow and duct sealing at commissioning decide whether you get the rated number or something well below it. How to find an installer covers what to ask.
A certified pair. The rating belongs to the condenser and air handler together. Check any pairing in the AHRI match checker before you order.
Questions?
Tell us where the house is and how long you plan to keep it, and we will tell you which tier we would put in — call or email. We still work in the trade and we install this equipment in the climate that runs it hardest.
(239) 266-9766 · sales@hvacsupplypro.com