How many watts does a Window AC (10,000 BTU) use?

A Window AC (10,000 BTU) draws 1,200 watts continuously once it's running, but its motor needs a brief surge of up to 3,600 watts to start. A generator has to cover that starting surge, not just the running load, or the motor won't start. Same caveat as the smaller window unit: no true nameplate LRA exists for this class under UL 484, so this starting-watts figure is a rough estimate, not real motor nameplate data.

Running it 8 hours/day costs roughly $48.96/month at the U.S. average residential rate (~$0.17/kWh, early 2026, per the EIA) — real rates vary a lot by state and utility. Use your own rate in the House calculator →

Generators that can run this

• Champion 4000W Dual Fuel Inverter (201050)
  3,000 W run · 4,000 W start · ~$749
• NOVUS NV4000iS
  3,300 W run · 4,125 W start · ~$599
• Champion 3500-Watt (100555)
  3,500 W run · 4,375 W start · ~$450

Prices as of July 2026 — check the current listing before buying.