Generator Size for a Central AC
Size a generator for a central air conditioner. Enter its running and startup watts to see the recommended size with surge headroom.
Runs locally in your browser — no upload, no trackingTry: Central AC running watts=3500, Central AC startup (surge) watts=7000 → 3,500 W, 7,000 W, 8,400 W, 10 kW
How to use
Central AC is usually the largest single surge in a home — a 3-ton unit can draw 3,500 running watts and 7,000 starting watts. This is why whole-house generators start around 10–15 kW. Enter your appliance's running and startup (surge) watts and press Calculate. The recommended size adds a 20% safety margin to the surge so the generator is never running at its limit.
These are typical figures — the plate on your central AC may read differently. If you run more than one device together, use the multi-appliance calculator instead.
FAQ
What size generator will run a central air conditioner?
A typical 3-ton central AC draws about 3,500 running watts and 7,000 starting watts. You need at least a 10 kW generator for the AC alone, and more to run anything else at the same time.