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How Many Watts Does a Central AC Use? 2, 3, and 4 Ton Specs
A central air conditioner compressor is rated at about 1,900 to 4,300 watts for 2 to 4 ton systems, based on its rated load amps at 230 volts. Goodman's GSXN3 spec sheet lists 8.4 amps for a 2 ton unit, 14.1 amps for 3 tons, and 18.5 amps for 4 tons, plus a much larger burst at startup. The indoor blower adds more on top.
Central AC amps and watts (manufacturer specs)
| Model | Size | Compressor rated load amps | Volts x amps at 230V | Locked rotor amps | Min. circuit ampacity / max breaker |
|---|---|---|---|---|---|
| Goodman GSXN3N2410 | 2 ton (24,000 BTU) | 8.4 A | About 1,930 VA | 41.2 A | 11.2 A / 15 A |
| Goodman GSXN3N3610 | 3 ton (36,000 BTU) | 14.1 A | About 3,240 VA | 87.4 A | 18.6 A / 30 A |
| Goodman GSXN3N4810 | 4 ton (48,000 BTU) | 18.5 A | About 4,260 VA | 124 A | 24.4 A / 40 A |
Source: Goodman GSXN3 specification sheet, 208/230V single phase. Volts x amps is our calculation and gives volt-amps (VA), a safe number for sizing backup power. Rated load amps is a rating, so actual running draw is usually lower. Locked rotor amps is the current the compressor can pull for an instant when it starts.
Find your own number: the nameplate on the outdoor condenser lists rated load amps (RLA), locked rotor amps (LRA), and minimum circuit ampacity.
How much electricity does central AC use?
As an upper bound, a 3 ton unit at its full rated load for 8 hours would use about 26 kWh (3,240 VA x 8 hours), about $4.41 at 17 cents per kWh. In practice the compressor cycles and often draws less than its rating, so your bill is usually lower. Your utility bill, compared month to month, shows your real cooling use.
Can a generator run central air?
Yes, but central AC is one of the hardest loads to back up. The compressor is hard-wired at 240V, so it needs a 120/240V generator connected through a transfer switch or interlock kit, and enough capacity to handle the startup burst on top of everything else running.
- DuroMax XP13000EH: 13,000 starting / 10,500 running watts on gasoline, 120/240V, 14-50R outlet. $1,299
- DuroMax XP15500HX: 15,500 starting / 12,000 running watts, two 14-50R outlets, CO alert. $2,299
Turn off other large loads (dryer, water heater, oven) while the AC starts. Hookup options are in How to Hook Up a Generator to Your House, and sizing is in What Size Generator Do You Need to Run a House?
Can a battery run central air?
A home battery with 240V output can, for a few hours. The Nature's Generator MyGrid 10K (10,496 Wh, 10 kW, 120/240V, $5,999.99 with a 50 A automatic transfer switch) would run a 3 ton compressor at its full rated 3,240 VA for about 2.9 hours (10,496 x 0.9 / 3,240), and longer as it cycles. Jackery lists its Explorer 5000 Plus (7.2 kW at 120/240V, from $3,149) as supporting ACs. Confirm your unit's locked rotor amps with us before buying.
Just cooling one room? A window unit or mini split uses far less: see How Many Watts Does a Window AC Use? and How Many Watts Does a Mini Split Use? Heat pumps work the same way; see How Many Watts Does a Heat Pump Use?
Need help sizing? Call 1-888-855-7286. Send us the RLA and LRA from your condenser's nameplate, and we will match you to a generator or battery system.
Central AC wattage FAQ
How many watts does a central AC use? About 1,930 to 4,260 VA for 2 to 4 ton Goodman GSXN3 compressors at their rated load amps, plus the indoor blower.
How many watts does a 3 ton AC use? Goodman rates its 3 ton GSXN3 compressor at 14.1 amps, about 3,240 VA at 230V.
How many amps does a central air conditioner draw? About 8.4, 14.1, and 18.5 rated load amps for 2, 3, and 4 ton Goodman GSXN3 units, with 41 to 124 amps for an instant at startup.
What size generator do I need for central air? A 120/240V generator with a large surge rating, such as the 10,500 running watt XP13000EH, connected through a transfer switch or interlock kit. Check your unit's LRA first.
How much does it cost to run central AC? Up to about $4.41 for 8 hours at a 3 ton unit's full rated load, at 17 cents per kWh. Actual cost is usually lower.