How many watts does a 4 ton air conditioner use?

The exact amount of Watts needed for a 4 ton air conditioner depends on the make and model of the AC unit, as well as how often it's running. A safe estimation is that it takes 14,000 Watts, or 4 Kilowatts. If you're using a generator, it's best to use a 17 KW generator to ensure that you have enough power.