What Is SEER2 and Why It Matters in 2026
The new efficiency rating that replaced SEER — and how to read it on a contractor quote.
SEER2 replaced the old SEER rating in January 2023 and is the only legal efficiency rating on equipment sold in the U.S. today. It uses tougher real-world test conditions — meaning a 14.3 SEER2 unit is roughly equivalent to a 15.0 SEER unit under the old standard.
Federal minimums by region
North region (above the 35th parallel): 13.4 SEER2 minimum for split-system AC, 14.3 SEER2 for heat pumps. South and Southwest: 14.3 SEER2 minimum for AC. These are the legal minimums — the floor of what you can buy new.
Most installed units today run 14.3-16 SEER2 (formerly 15-17 SEER). Premium units hit 20-22 SEER2 and cost 30-50% more — usually only worth it in hot climates with high electric rates.
Reading a contractor quote
Every quote should specify the SEER2 AND the EER2 (steady-state efficiency at peak load). High SEER2 with low EER2 means efficiency drops off in hot weather — the worst time to need it.
Also check the HSPF2 (heating efficiency) rating for heat pumps. 7.5+ HSPF2 is the practical minimum for cold-climate performance.