Mini split listings are full of efficiency numbers. Two matter most.
SEER2: Cooling Efficiency
SEER2 measures how much cooling you get per unit of electricity over a typical season. Higher is better. Many of the 12,000 BTU units we cover sit around 19 to 22 SEER2.
HSPF2: Heating Efficiency
HSPF2 does the same for heating. Higher is better. If you will use the mini split mainly for heat, HSPF2 matters more than SEER2.
Why the “2”?
Since 2023, US ratings use an updated Department of Energy test that better reflects real installations. The new SEER2 and HSPF2 numbers come out lower than the old SEER and HSPF numbers for the same unit, so only compare SEER2 with SEER2, not with an old SEER figure. Some listings still quote old SEER, which makes direct comparisons tricky.
ENERGY STAR
An ENERGY STAR label means the model met efficiency criteria set by the EPA. Several units we cover list it, including the Cooper & Hunter MIA and DELLA Serena.
What the Ratings Do Not Tell You
They are seasonal averages. They do not tell you how much heat a unit still delivers on your coldest nights. For that, check the minimum heating temperature and, where published, the heating capacity at 5°F.
Want to see how a mini split fits with the rest of your home? Our Whole-Home Energy Calculator adds up what a thermostat, an EV charger, a backup battery and more would mean for your monthly bill.