How much does it cost to run a window air conditioner per hour?

At the U.S. average of 18.0¢/kWh, a typical certified unit costs 6.6¢ (5,000 BTU), 9.6¢ (8,000 BTU), 12.0¢ (10,000 BTU), 15.3¢ (12,700 BTU), 16.8¢ (14,000 BTU), 25.8¢ (20,900 BTU), 32.6¢ (24,000 BTU) per hour at full power.

How many watts does a window air conditioner use?

Divide its BTU by its CEER. Typical certified units draw 365 W at 5,000 BTU, 533 W at 8,000 BTU, 667 W at 10,000 BTU, 847 W at 12,700 BTU, 933 W at 14,000 BTU, 1432 W at 20,900 BTU, 1805 W at 24,000 BTU. Inverter units often run below full power once the room is cool, so real use is usually lower.

How much does a window AC add to the electric bill per month?

Running 8 hours a day for 30 days, a typical 8,000 BTU unit adds about $23 and a 12,000 BTU unit about $37 at the U.S. average price. In Hawaii, where it runs the most hours, a 10,000 BTU unit costs about $562 over a whole year.

Is it cheaper to run a window AC or central air?

To cool one or two rooms, a window unit is usually cheaper because it cools only where you are. To cool a whole house, central air or a heat pump is more efficient: certified window units reach 12-18 CEER, while heat pumps and central systems are rated from about 14 to over 30 SEER2 (not directly comparable, but the gap is real).

How much does a window air conditioner cost to run?

A typical 10,000 BTU window unit costs about 12¢ an hour, $1 for an 8-hour day and $29 a month of daily use.

That is at the U.S. average of 18.0¢ per kWh. Your state's price and climate change it a lot: see the table below or use the calculator.

Cost by size

Size	Watts	Per hour	8-hour day	Month
5,000 BTU	365	6.6¢	$0.53	$16
8,000 BTU	533	9.6¢	$0.77	$23
10,000 BTU	667	12.0¢	$0.96	$29
12,700 BTU	847	15.3¢	$1.22	$37
14,000 BTU	933	16.8¢	$1.35	$40
20,900 BTU	1432	25.8¢	$2.07	$62
24,000 BTU	1805	32.6¢	$2.60	$78

Typical (median-efficiency) ENERGY STAR unit of each size at full power. Month: 8 hours a day for 30 days.

Calculator

1. The air conditioner type its size and CEER (on the yellow EnergyGuide label)

Cooling capacity BTU/hCEER efficiency, higher is better

2. How you use it

StateElectricity ¢ per kWhHours a day at full powerDays a year from your state's climate

Per year: $141
Per month of use: $26
Per day: $0.85
Per hour: 10.7¢
Power draw: 667 W

Electricity used: 880 kWh a yearAn old 9 CEER unit of the same size would cost $188

Power draw is capacity divided by CEER, which already includes standby power. Inverter units often run below full power, so real use can be lower. Electricity prices: U.S. EIA residential averages (12 months to July 2026). Days a year start from your state's cooling degree days (NOAA 1991-2020 normals).

By state

Yearly cost of a 10,000 BTU unit in every state$2-$562

Typical certified 10,000 BTU unit (15.0 CEER), state electricity price and typical cooling hours from the state's cooling degree days.

State	¢/kWh	Hours	Per year
Hawaii	43.7	1925	$562
Arizona	15.5	1775	$183
Florida	15.4	1625	$167
Texas	16.0	1300	$139
District of Columbia	24.2	725	$118
Nevada	13.6	1225	$111
Alabama	16.5	1000	$111
Louisiana	13.1	1275	$110
South Carolina	15.7	1025	$107
Mississippi	14.9	1075	$106
Maryland	22.3	700	$102
California	33.1	450	$99
New York	28.4	500	$94
Georgia	15.1	900	$90
New Jersey	23.6	525	$84
Virginia	16.6	725	$79
Oklahoma	13.6	825	$75
Tennessee	13.7	825	$74
Pennsylvania	20.8	525	$74
North Carolina	14.9	750	$73
Arkansas	13.5	775	$70
Kansas	15.1	675	$67
Rhode Island	29.4	350	$67
Connecticut	28.2	350	$66
New Mexico	15.2	600	$62
Missouri	13.9	650	$60
Massachusetts	30.4	300	$60
Delaware	18.0	500	$59
Kentucky	14.0	625	$58
Illinois	19.0	450	$56
New Hampshire	26.8	300	$55
Utah	13.3	600	$53
Ohio	18.3	425	$53
Indiana	17.1	450	$52
West Virginia	15.7	475	$50
Michigan	21.0	325	$45
Nebraska	12.9	475	$41
Vermont	23.9	250	$40
Idaho	12.7	450	$37
Wisconsin	18.8	300	$37
Iowa	14.1	400	$37
Minnesota	16.2	325	$34
Maine	29.3	175	$33
Colorado	16.6	300	$33
South Dakota	14.3	325	$31
Montana	13.9	200	$18
Oregon	15.6	175	$18
North Dakota	12.5	225	$18
Wyoming	14.2	175	$17
Washington	14.2	125	$12
Alaska	27.0	0	$2

Electricity: U.S. EIA residential averages (12 months to July 2026). Climate: NOAA 1991-2020 normals.

Questions4

How much does it cost to run a window air conditioner per hour?: At the U.S. average of 18.0¢/kWh, a typical certified unit costs 6.6¢ (5,000 BTU), 9.6¢ (8,000 BTU), 12.0¢ (10,000 BTU), 15.3¢ (12,700 BTU), 16.8¢ (14,000 BTU), 25.8¢ (20,900 BTU), 32.6¢ (24,000 BTU) per hour at full power.
How many watts does a window air conditioner use?: Divide its BTU by its CEER. Typical certified units draw 365 W at 5,000 BTU, 533 W at 8,000 BTU, 667 W at 10,000 BTU, 847 W at 12,700 BTU, 933 W at 14,000 BTU, 1432 W at 20,900 BTU, 1805 W at 24,000 BTU. Inverter units often run below full power once the room is cool, so real use is usually lower.
How much does a window AC add to the electric bill per month?: Running 8 hours a day for 30 days, a typical 8,000 BTU unit adds about $23 and a 12,000 BTU unit about $37 at the U.S. average price. In Hawaii, where it runs the most hours, a 10,000 BTU unit costs about $562 over a whole year.
Is it cheaper to run a window AC or central air?: To cool one or two rooms, a window unit is usually cheaper because it cools only where you are. To cool a whole house, central air or a heat pump is more efficient: certified window units reach 12-18 CEER, while heat pumps and central systems are rated from about 14 to over 30 SEER2 (not directly comparable, but the gap is real).

Cut the cost

Pick the right size: an oversized unit cycles and wastes energy. Size calculator
Compare CEER: in the same size, a 15 CEER unit uses about 20% less electricity than a 12 CEER unit.
Seal the side panels and keep blinds closed on sunny afternoons.
Clean the filter every few weeks in summer; a clogged filter cuts airflow and efficiency.