Ratings & Efficiency
What Is SEER2?
SEER2 (Seasonal Energy Efficiency Ratio 2) is the U.S. Department of Energy rating for how much cooling an air conditioner or heat pump delivers per watt-hour of electricity across a typical cooling season. It replaced SEER in 2023 under a tougher test procedure that better reflects real duct resistance. Higher numbers mean less electricity for the same cooling.
Also called: Seasonal Energy Efficiency Ratio 2 · SEER
Why it matters to you
North Carolina sits in the DOE's Southeast region, where a new split-system air conditioner under 45,000 BTU/h must reach 14.3 SEER2 — higher than the 13.4 SEER2 floor in northern states. On the Crystal Coast, where cooling runs long and humid from May into October, the rating does more work here than it would further north: by rating arithmetic, an 18 SEER2 system uses about 21% less electricity than a 14.3 SEER2 one for the same cooling (1 − 14.3/18).
What to do about it
Ask for the outdoor and indoor model numbers on every quote and look that exact matched pair up in the AHRI Directory — the SEER2 rating belongs to the combination, not the outdoor unit alone. Pairing a high-SEER2 condenser with an old indoor coil does not deliver the rated number.
By the numbers
| Equipment | Region | Minimum SEER2 |
|---|---|---|
| Split-system AC, under 45,000 BTU/h | Southeast (incl. NC) | 14.3 |
| Split-system AC, 45,000 BTU/h and above | Southeast (incl. NC) | 13.8 |
| Split-system AC | National baseline (North — no regional uplift) | 13.4 |
| Split-system heat pump | National (no regional split) | 14.3 |
SEER2 minimums by equipment type (since January 1, 2023)
Common questions
- What is the minimum SEER2 for a new air conditioner in North Carolina?
- North Carolina is in the DOE's Southeast region. Since January 1, 2023, a new split-system air conditioner rated under 45,000 BTU/h must be at least 14.3 SEER2, and one rated 45,000 BTU/h or above at least 13.8 SEER2. Split-system heat pumps follow a single national minimum of 14.3 SEER2 rather than a regional one.
- Is SEER2 the same as the old SEER number?
- No. SEER2 uses a test procedure with higher external static pressure, which is closer to the duct resistance a system actually sees. The same equipment scores lower under SEER2 than it did under SEER, so a 14.3 SEER2 unit is roughly comparable to a 15 SEER unit under the old test. Comparing a SEER2 quote against an older SEER brochure will understate the new system.
- Does a higher SEER2 matter on the coast?
- It matters more here than in a short-cooling-season climate, simply because the hours add up — eastern North Carolina cools for a large part of the year. But SEER2 measures seasonal cooling efficiency only. For a heat pump that also heats the house, weigh HSPF2 alongside it, and remember that correct sizing and a sound duct system affect real-world consumption as much as the nameplate rating does.
- What SEER2 should I actually buy?
- There is no single right answer — it depends on how long you will keep the house, how much the system runs, and what the equipment costs you. The arithmetic is simple: the percentage reduction in cooling electricity between two ratings is 1 minus the lower rating divided by the higher. Ask your installer to show the AHRI-matched rating for each option so you are comparing like with like.
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