Room air conditioners running costs

Reading the room air conditioner ranking

Room air conditioners post the second-widest running-cost spread of any category we track, right behind dehumidifiers, for a similar reason: BTU cooling capacity varies enormously across this class, from a unit built for a small bedroom to one built for a large open room, and capacity alone explains a large share of the gap between the cheapest and priciest models here.

Combined Energy Efficiency Ratio (CEER) is the class's real efficiency figure, capturing cooling output per watt including standby draw. The efficiency ranking sorts by CEER adjusted for BTU capacity, while the raw leaderboard above naturally favors smaller-capacity units regardless of how efficiently they convert electricity into cooling.

Across the 404 certified room air conditioners we track, running cost ranges from $51 to $389 a year with a median of $99/yr; most of the 404 models we track cluster toward the cheap end of that range, with a smaller group of pricier models stretching the top up to $389/yr. Our dataset does not distinguish window from portable installation type, so that design difference, which affects how directly a unit vents heat outside, is not something this specific ranking can show.

What to weigh when comparing models

Size the unit to the room rather than buying the highest BTU figure available; an oversized unit cycles on and off rapidly without fully dehumidifying the air, while an undersized one runs constantly and still struggles to cool. Once BTU capacity fits your room, CEER is the number to compare, and using a timer or eco mode instead of a fixed low setting will move your real bill more than almost any spec on this page.

Because a correctly sized unit is quieter and cycles less than either an oversized or undersized one, running-cost efficiency and comfort tend to point the same direction here: get the BTU sizing right first, then use CEER to pick between similarly sized options.

How we score this class

Every figure here follows the same formula: each model's published annual kWh from ENERGY STAR, multiplied by the US average residential rate of $0.1856/kWh. Full methodology on how we score, or use the calculator.