How Much Does It Cost to Run a Window Air Conditioner (8,000 BTU)?

About 650 to 900 W while the compressor runs, depending on efficiency. Divide the BTU rating by the EER or CEER on the yellow EnergyGuide label to get the running watts: 8,000 divided by 11 is roughly 730 W.

At 750 W and a 60 percent duty cycle, 24 hours uses about 10.8 kWh. At the national average rate that is close to $1.90 a day. In Hawaii it would be over $4.

Turning it off, or setting it several degrees higher, almost always costs less. A room that warms up while you are out needs a burst of compressor time to recover, but that burst is smaller than the energy spent holding a cool temperature all day against heat coming through the walls and windows.

A mid-size station with a 1,500 W or larger inverter can usually start an 8,000 BTU unit, but it will drain a 1 kWh battery in about two hours of compressor time. See the power station sizer for the capacity you would need.

About $19 a month at the national average rate. At 750 W for 8 hours a day and a 60 percent duty cycle it uses 0.75 x 8 x 0.6 = 3.6 kWh a day, or 108 kWh over 30 days, and 108 x $0.173 is about $19. At 12 hours a day in a hot month it is about 162 kWh, roughly $28.

About 13 cents for each hour the compressor runs, since 0.75 kWh x $0.173 = $0.13. Averaged over an hour with the compressor cycling at 60 percent, it is about 8 cents an hour.

Moderately. At about 750 W it draws roughly 6.3 A at 120 V and uses around 3.6 kWh on a typical 8 hour day. That is about a quarter of what a 3 ton central AC uses on the same schedule, but it cools only one room.

A window AC is cheaper when you only need to cool one or two rooms. On the defaults used on this site, an 8,000 BTU window unit uses about 3.6 kWh a day and a 3 ton central system about 14 kWh, so one window unit costs about 62 cents a day against about $2.42. Once you are running three or four window units, the gap closes and an efficient central system or heat pump can come out ahead.

Yes, if the generator can cover the start-up surge. The compressor needs about 2,200 W for a moment at start and about 750 W while running, so look for a generator whose starting or peak rating is at least 2,200 W. Leave headroom if anything else is plugged in at the same time.

Cut compressor run time. Set the fan to auto, raise the setpoint a few degrees and add a ceiling fan, clean the filter monthly, and shade the window. Each hour of compressor time you avoid saves 0.75 kWh, about 13 cents at the national average rate.