How many watts does a central AC use?
Updated
Running watts
3,800 W
Starting watts
11,500 W
Energy per day
30.4 kWh
A central AC typically draws about 3,800 watts while running and up to 11,500 watts for a second or two when the motor starts. At about 8 h of use a day, that is roughly 30.4 kWh per day. These are typical values from generator wattage charts: the label on your own appliance (or its EnergyGuide sticker) gives the exact figure.
What size generator do I need for a central AC?
Plan for at least 13,800 W: 11,500 W to get through the start-up surge, plus a 20% margin so the generator never runs flat out. Of the common sizes, a 15,000 W generator is the smallest that fits.
| Generator | Can it run a central AC? |
|---|---|
| 2,000 W | No |
| 3,500 W | No |
| 5,000 W | No |
| 7,500 W | No |
| 10,000 W | No |
| 15,000 W | Yes |
How long will a power station run a central AC?
Running continuously at 3,800 W, assuming 85% of the battery is usable. The station's AC output must also handle the 11,500 W start-up surge.
| Battery capacity | Runtime |
|---|---|
| 1,000 Wh | about 13 min |
| 2,000 Wh | about 27 min |
| 3,600 Wh | about 48 min |
Running more than one appliance?
Starting surges don't add up the way running watts do. Pick everything you want to power to get your real number.
Open the Generator Size Calculator for Your HomeFrequently asked questions
What size generator do I need to run a central AC?
At least 13,800 W: 11,500 W to cover the start-up surge, plus a 20% safety margin.
Can a 2,000 watt generator run a central AC?
No. It needs about 11,500 W for a second or two when it starts, more than 2,000 W.
Can a 3,500 watt generator run a central AC?
No. It needs about 11,500 W for a second or two when it starts, more than 3,500 W.
How long will a 1,000 Wh power station run a central AC?
About 13 min, assuming 85% usable capacity, as long as the station's AC output is rated for 11,500 W of surge.
Never run a generator indoors or in a garage: see the CPSC safety guide.