SEER2 and HSPF2 are the efficiency ratings on current air conditioners and heat pumps. This guide explains what they mean, what changed in 2023 and how to use them when comparing equipment.
SEER2 is the seasonal energy efficiency ratio under the current federal test procedure. It describes cooling efficiency over a typical cooling season, as the heat removed from the home divided by the electricity used. HSPF2 is the heating seasonal performance factor under the same updated procedure, and it applies to heat pumps in heating mode. For both, a higher number means more output per unit of electricity.
A third rating, EER2, measures cooling efficiency at a single fixed set of conditions rather than across a season. It appears in some regional requirements, discussed below.
The U.S. Department of Energy updated its efficiency standards and test procedure for central air conditioners and heat pumps, and the new rules took effect January 1, 2023. The ratings changed names to add the 2, as in SEER2 and HSPF2, to mark that they come from a revised test.
The main change in the test is that it better reflects real installations, including more resistance to airflow from ductwork than the older procedure assumed. As a result, a given piece of equipment generally scores lower on SEER2 than it did on the old SEER. That does not mean the equipment got worse. The two scales are not directly comparable, and you should not subtract numbers in your head to convert one to another.
Existing equipment is not affected. The standards govern what manufacturers may build and what installers may put in, not what you already own. A working air conditioner is not made illegal by the change.
You may see both old and new ratings on websites and in older brochures during the changeover. If a listing does not say SEER2, check the date and the model, and confirm the current rating with the installer or the manufacturer's specification sheet before comparing it with anything else.
The standards for air conditioners vary by region. Federal rules divide the country into a north region and a south region, with additional requirements in the hot, dry southwest. The south and southwest require a higher minimum for smaller split-system air conditioners than the north does, and the southwest adds an EER2 requirement. Heat pumps follow a single national minimum for both SEER2 and HSPF2.
Which region applies depends on where the equipment is installed, and for some regions the installation date determines compliance, not the manufacture date. Because that is the kind of detail where mistakes are costly, ask your installer which minimums apply and confirm the model you are getting meets them. We do not list the specific minimums here, since the rules are detailed and organized by type, capacity and region.
Compare equipment on the same scale: SEER2 to SEER2 and HSPF2 to HSPF2. A higher rating can lower operating cost, but the return depends on how much you run the system, your electricity rates and how well the installation matches the house. A very high rating on an oversized or badly ducted system will not deliver what the label implies.
Installed performance is what you pay for. Ratings come from laboratory conditions with matched components, so leaky ducts, low airflow, a wrong refrigerant charge or poor sizing can erase part of the advantage. Ask how the installer verifies airflow and charge at the end of the job.
Equipment designs differ in how they run. Single-stage units operate at full output whenever they are on. Two-stage and variable-speed units can run at lower output, which tends to bring higher ratings, quieter operation and more even temperatures. They also add cost and complexity, which is worth discussing during a quote.
Efficiency ratings reflect design, but not how long a system lasts or how easy it is to service. Our guide on how long an HVAC system lasts covers what affects longevity.
A reasonable approach is to decide what you will actually do with the extra efficiency. A home with long cooling seasons and high electricity rates gets more out of a high rating than a home that rarely runs the air conditioner. Ask for the comparison to be shown for your own use pattern.
HSPF2 applies only to heat pumps. Gas furnaces carry an AFUE rating, the portion of fuel that ends up as heat in the home. If you are choosing between those two kinds of heating equipment, our heat pump versus furnace guide explains how to compare them.
For cooling, the AC repair and replacement page covers the sizing and matching questions that go with a new system, and the heat pump installation page does the same for heat pumps. Incentives that were once tied to efficiency tiers have changed, so confirm with a tax professional or your utility what is current rather than assuming.
Keep a copy of the specification sheet and the model numbers of the indoor and outdoor units after installation. Those records make it easier to confirm ratings later, check warranty terms and answer questions from an inspector, an insurer or a future buyer of the home.
SEER2 comes from a revised test that better reflects real installations. The same equipment generally scores lower on SEER2, so the scales are not directly comparable.
It is the heating efficiency rating for heat pumps under the 2023 test procedure. Higher means less electricity for the same amount of heat.
No. They apply to equipment manufactured and installed under the new rules, not to systems already in your home.
For air conditioners, yes: the north, south and southwest regions have different requirements. Heat pumps follow a national minimum. Ask your installer which rules apply.
Tell us what your system is doing and we will follow up with next steps.