How much does a portable air conditioner cost to run?
At the current average residential rate of 18.34¢ per kWh, a typical 1,200 W portable air conditioner costs about 22¢ per hour — around $38.15 a month and $458 a year at 40 hours a week.
The rate and formula behind these numbers
kWh = watts × hours ÷ 1,000, and cost = kWh × rate. The yearly figure assumes the same weekly pattern all year (× 52); the monthly figure is the yearly one ÷ 12.
Electricity rate: 18.34¢ per kWh — the US EIA Electric Power Monthly for June 2026, the latest month EIA has published (US average across all states). Source: US EIA Electric Power Monthly. Checked September 2, 2026. It excludes the fixed monthly customer charge, which you pay regardless of use.
Portable units are the priciest way to cool a room per degree, and the single-hose design is why: the air it blows out of the window has to be replaced by air pulled in from everywhere else, including outside. A window unit of the same rating usually does the same job for less, which is the comparison worth making before you shop. The compressor also cycles rather than running flat out, so a real afternoon costs less than the plate wattage suggests — sizing the unit to the room moves the bill more than any eco setting.