The cooling-efficiency rating for ACs and heat pumps — higher is better.
SEER2 measures how efficiently an air conditioner or heat pump cools over a season. It replaced the older SEER rating in 2023 using a tougher test that better reflects real ductwork, so SEER2 numbers run slightly lower than the old scale. A higher SEER2 means less electricity for the same cooling.
Why SEER2 matters
Efficiency terms affect operating cost, rebate eligibility, and how confidently you can compare one quote against another. A higher rating can lower utility bills, but only if the system is sized, matched, and installed correctly.
When you'll see this term
You will usually see this term on equipment proposals, AHRI matches, rebate paperwork, energy labels, and replacement comparisons.
Questions to ask your technician
- How does this rating change my expected operating cost?
- Does this equipment qualify for any current utility or manufacturer rebate?
- Is the indoor and outdoor equipment matched so the rating is valid?
AFUE, SEER2 & HSPF: efficiency ratings explained
Related terms
- AFUE (Annual Fuel Utilization Efficiency)
- How efficiently a furnace turns fuel into heat, as a percentage.
- HSPF2 (Heating Seasonal Performance Factor 2)
- The heating-efficiency rating for heat pumps — higher is better.
- BTU (British Thermal Unit)
- The basic unit of heat energy used to measure HVAC capacity.
- Ton (of cooling)
- A measure of AC/heat-pump capacity; 1 ton = 12,000 BTU/hr.