SEER2

What the number means

SEER2 compares the cooling a system delivers over a typical season with the electricity it uses to do it. A higher SEER2 means fewer kilowatt-hours for the same cooling. It doesn't measure capacity: a 2-ton and a 4-ton system can carry the same SEER2. Size comes from tonnage and the load calculation; efficiency comes from SEER2.

It travels with two related metrics. EER2 measures cooling efficiency at a single hot-weather condition, and HSPF2 measures a heat pump's heating efficiency. Since January 1, 2023, DOE's standards for central air conditioners and heat pumps have used SEER2, EER2 and HSPF2, metrics DOE created because the test procedures changed to better reflect real-world installation and use ¹.

Why the "2" matters

SEER and SEER2 come from different tests, so a number on an old brochure and a number on a current certificate aren't directly comparable ¹. When a customer says the old unit was "14 SEER," don't line that up against a SEER2 figure as if they were the same scale. Compare current options with current ratings.

The federal minimums

DOE sets a floor, and for air conditioners the floor depends on the region where the system is installed ¹²:

The Southwest also has EER2 minimums for air conditioners. Check DOE's regional guidance for which region your state falls in, because your lowest-priced option has to clear that region's floor, not just the national one.

Quote the rating of the exact match

A split system's rating belongs to the combination of indoor and outdoor equipment, not the condenser alone. AHRI's directory lists certified matched systems and generates a certificate showing that combination's certified ratings ³. Put that number on the proposal, never the top figure for the product line.

Example: A homeowner compares a 14.3 SEER2 option with an 18 SEER2 option. Suppose the house needs 24,000,000 Btu of cooling in a season. At 14.3 SEER2 that's about 24,000,000 ÷ 14.3 ÷ 1,000 = 1,678 kWh; at 18 SEER2, about 1,333 kWh. The difference is 345 kWh. At $0.15 per kWh that's about $52 a year. In a hotter climate with more cooling hours, the gap grows. The numbers are made up for illustration; show your own assumptions whenever you put a savings figure in writing.

Common mistakes

• Promising a bill number. SEER2 is a test rating. Actual use depends on the climate, the thermostat, the ducts and how well the system was sized and installed.
• Mixing up efficiency and size. A higher SEER2 doesn't fix an oversized or undersized system. Size from a Manual J load calculation first.
• Reusing an old coil and quoting the new unit's rating. If that combination isn't certified, don't print a rating for it.
• Tiers that only differ on paper. In good, better and best options, each step up in SEER2 should come with a real difference in equipment, and the proposal should show what the customer gets for the price difference.

Rebates and incentives often key off efficiency ratings, but their rules change, so treat any incentive as conditional on the program's current terms. The HVAC estimate guide shows where ratings go on a proposal.