Efficiency decides how much cooling you get per unit of electricity. The catch is that the ratings are not interchangeable: CEER is a single-point rating used for window and portable units, SEER2 is a seasonal rating used for mini-splits, and converting one into the other would invent a number nobody published. So each unit here is ranked against the units measured the same way.
The short answer
The highest CEER we list is the GE Profile Inverter Smart Window Air Conditioner 8,000 BTU in White at CEER 16, a window unit covering up to 350 sq ft, in stock at Abt Electronics for $344. CEER only compares window and portable units: a mini-split's SEER2 and a window unit's CEER are measured differently and cannot be ranked against each other, so each unit below is placed against the units rated on its own scale.
CEER 16 · covers up to 350 sq ft · 8,000 BTU
We use the manufacturer's own published rating and place each unit against the units on the same scale, so a mini-split's SEER2 is never ranked against a window unit's CEER. Units that publish no rating are excluded from this page rather than given an invented score, and ENERGY STAR on its own is treated as a badge, not a ranking, because it says a unit cleared a bar and not by how much. Nobody can pay for placement.
Read our full methodology
