How much does it cost to run a room air conditioner?

A room air conditioner certified by ENERGY STAR costs about $51 to $389 a year to run at the US average residential electricity rate of $0.1856/kWh, based on 404 models we track. The class median is $99/yr. The cheapest to run is the Tcl T05WV9M at about $51/yr, while the priciest models in the class run closer to $389/yr. Running cost in this class is driven mostly by BTU cooling capacity and compressor efficiency (CEER), covered in detail below.

What it costs

Across the 404 ENERGY STAR certified room air conditioner models we track, annual running cost ranges from $51/yr to $389/yr, with a class median of $99/yr, all computed at the US average residential rate of $0.1856/kWh. That is a spread of $338 a year between the cheapest and priciest model we track, which over a typical decade-long appliance life is $3380 of difference before the purchase price even enters the math.

What drives the running cost

A room air conditioner's running cost tracks how much cooling capacity it has and how efficiently it converts electricity into that cooling:

• BTU cooling capacity. A higher-BTU unit is sized for a bigger room, and generally uses more electricity per hour of operation than a smaller unit, regardless of efficiency.
• Combined Energy Efficiency Ratio (CEER). This federal efficiency figure captures cooling output per watt, including standby power; a higher CEER means less electricity for the same BTU of cooling.
• Window vs. portable design. Window units generally vent heat more directly to the outside than portable units, which often lose some cooled air through their exhaust hose, so a portable unit can need to run longer for the same comfort level.
• Thermostat and mode usage. Running on a fixed low temperature around the clock uses far more energy than using a thermostat setting, eco mode, or a timer to match cooling to when the room is actually occupied.

How to lower it

• Size the unit to the room; an oversized unit cycles on and off rapidly without fully dehumidifying the air, while an undersized one runs constantly and still struggles to cool.
• Use a programmable timer or the unit's eco/sleep mode instead of running full cooling continuously, especially overnight or when the room is empty.
• Seal gaps around a window unit's install kit, and keep doors to the cooled room closed, so conditioned air is not lost to the rest of the house.
• Clean or replace the air filter regularly; restricted airflow makes the compressor work harder for the same cooling output.

The cheapest room air conditioner to run

These are the five cheapest room air conditioner models to run among the ones we track, ranked by estimated dollars per year. See the full leaderboard for all 150 ranked.

Calculate your own

These figures assume the US average electricity rate. If your local rate is higher or lower, or you want to check a specific model's real annual kWh, use the running-cost calculator to swap in your own rate and see the yearly cost update live.