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Updated July 2026 rate dataHeating & CoolingSourced from U.S. EIA
A unit's draw follows its cooling capacity and efficiency rating, so a bigger room or a hotter afternoon means more compressor runtime. Pick your unit's size, your daily hours, and your state below to price it.
EIA residential average, July 2026. Your utility's exact rate is on your bill.
Real-time math: 900 W × your state's rate, accumulating live. Thermostatically controlled units cycle on and off, so average use is usually below the flat-out figure.
Run like this for a year and it adds about $481 to your electricity bill.
Power draw estimates from BTU rating and efficiency (watts ≈ BTU/hr ÷ EER); a 10,000 BTU/hr unit drawing 900 W implies an EER of about 11.1. Rate basis: 18.31¢/kWh U.S. average (EIA, July 2026). Compressor cycling lowers real-world cost.
Energy: 7.2 kWh per day · 2,628 kWh per year, at 18.31¢/kWh (U.S. average).
Wattage is the number that decides everything else. The table below runs the actual figures through this page's calculator at the U.S. average rate of 18.31¢ /kWh, so you can see the running cost jump as the load climbs. Change any value above and the whole page recalculates.
| Watts | Power draw | Per hour | Per month (8 h/day) |
|---|---|---|---|
| 300 W | 300 W draws 0.30 kW | $0.055 | $13.37 |
| 1,600 W | 1,600 W draws 1.60 kW | $0.29 | $71.29 |
| 2,900 W | 2,900 W draws 2.90 kW | $0.53 | $129 |
| 4,200 W | 4,200 W draws 4.20 kW | $0.77 | $187 |
Basis: July 2026 U.S. average residential rate of 18.31¢ /kWh (EIA Electric Power Monthly, Table 5.6.A). Your state's rate is applied as soon as you pick it above.
An AC's power draw is its cooling capacity (BTU/hr) divided by its efficiency (EER). A 10,000 BTU/hr unit drawing 900 W has an implied EER of about 11.1; at EER 12, it draws about 830 W for the same cooling. The EnergyGuide label lists the exact watts and yearly cost estimate for your model.
The compressor doesn't run every second. Once the room reaches the setpoint it cycles off; in milder weather a unit might draw full power only half the time. Hot afternoons with a big cooling gap push duty cycles toward 100%.
Central systems cool the entire house, so their hourly cost is several times a window unit's — but per degree of cooling across the whole home they can be comparable. Cooling one occupied room with a window unit is almost always the cheaper strategy for a household.
The same 10,000 BTU unit costs about $0.115 per hour in Nevada and $0.432 per hour in Hawaii. Summer bills concentrate this: 200 hours of July runtime means a $22.99–$86.40 spread between states.
Biggest savings first.
A 10,000 BTU window unit (≈900 W) running 24 hours flat-out uses about 21.6 kWh — roughly $4 at the U.S. average rate (18.31¢/kWh). A 3-ton central system flat-out would be about $16. Real bills are lower because compressors cycle.
At 8 hours a day, a 10,000 BTU window AC is about $31/month at the U.S. average rate. Central AC at the same daily schedule runs roughly $85–125/month depending on tonnage and rate. Duty cycle and insulation swing these numbers a lot.
Window units: 5,000 BTU ≈ 500 W, 8,000 BTU ≈ 720 W, 10,000 BTU ≈ 900 W, 12,000 BTU ≈ 1,060 W (at a typical EER of 10). Central systems: about 1,200 W per ton, so 2-ton ≈ 2,400 W and 3-ton ≈ 3,600 W.
Turning it off (or setting it well higher) while you're out wins in most homes. 'All day' running only makes sense with a very efficient envelope or a utility rate that penalizes evening peak use — a programmable thermostat pre-cooling an hour before you return is the practical middle ground.
Rate basis: EIA residential average, July 2026 (retrieved from Electric Power Monthly Table 5.6.A). Estimates are for planning, not billing.
