What will a 3,500 watt generator run?

A 3,500 watt generator is the sweet spot for a lot of people. It's big enough for one RV air conditioner or a home's essentials, and small enough to move around. Here's what it can and can't handle.

First, which 3,500 is it?

Every generator has two ratings:

• Running (rated) watts: what it gives all day.
• Starting (peak) watts: a short burst for motors.

"3,500 W" can mean either. On many inverter models it's the starting figure, with running around 3,000. On many open-frame models it's the running figure, with starting higher. Check the spec sheet. Below, we assume the tougher case: 3,000 running and 3,500 starting. If yours is 3,500 running, you have more room.

Dual-fuel models make less power on propane. For example, a Westinghouse dual-fuel manual lists 9,500 running watts on gas and 8,500 on propane. Check the propane rating if you'll use it.

Will a 3,500 watt generator run an RV air conditioner?

AC	Running W	Starting W	On 3,000 run / 3,500 start
13,500 BTU RV roof	1,500–2,000	2,800–3,500	Yes, plus lights, TV and chargers
15,000 BTU RV roof	2,000–2,500	3,500–4,500	Borderline. A soft start makes it comfortable
Two ACs (50 amp RV)	3,000–4,000	4,500+	No, not both at once

AC ranges are from Champion's chart. The tool above is set to a 13,500 BTU AC on a generator rated 3,000 running and 3,500 starting. Change it to match your AC and generator.

Will it run a 30 amp camper? A 50 amp camper?

• 30 amp camper: yes, for most. A 30 amp RV can only draw 3,600 W at most (30 A × 120 V). One AC plus lights, TV and the fridge fits. Running the AC and the microwave together will be close to the limit. See what size generator for a 30 amp RV.
• 50 amp camper: partly. It will run one AC and the basics through an adapter, but not two ACs, the electric water heater and the microwave together.

Will a 3,500 watt generator run a house?

Not a whole house, but the essentials, yes. Here's a common list, using our calculator's figures:

Appliance	Running W	Starting W
Fridge	400	1,200
Sump pump (1/2 HP)	1,000	2,150
Furnace fan (1/3 HP)	700	1,800
Lights, Wi-Fi, chargers, TV	345	same

• Running: 2,445 W
• Biggest surge: the sump pump, 2,150 − 1,000 = 1,150 W
• Starting: 2,445 + 1,150 = 3,595 W

That's just over a 3,500 W peak. Because the sump pump switches on by itself, it may trip the generator when it kicks on with everything else running. Leave one item off (say, the furnace fan on a mild night), or choose a unit rated 3,500 running watts, which handles the list easily. Connecting to house circuits needs a transfer switch or interlock installed by a licensed electrician. Never backfeed through a wall outlet or dryer outlet.

More "will it run" answers

Appliance	On a 3,500 W generator
Refrigerator (400 run / 1,200 start)	Yes. Two fridges, yes
Window AC, 8,000–12,000 BTU	Yes, plus a fridge
Gas furnace fan	Yes. An inverter is the safer pick for furnace electronics. See generator for a gas furnace
Well pump, 1/2 HP	Maybe. It needs a 240 V outlet if the pump is 240 V, and Franklin Electric says 3 kW minimum for a 2-wire pump. Little room for anything else. See generator for a well pump
Well pump, 1 HP	No. Franklin says 4–6 kW minimum
Mini split, 12,000 BTU	Watts, yes (about 900–1,000 W). But many run on 240 V. See will a generator run a mini split?
Microwave, 1,000 W	Yes
Electric water heater (4,500 W, 240 V)	No
120 V welder	Borderline. Champion lists 1,800–2,500 running and 3,600–5,000 starting
Air compressor, 1 HP	Unlikely. Honda and Champion both list about 1,500 running and 4,500 starting
Circular saw, 7-1/4"	Yes (1,400 run / 2,300 start)

Figures are from Champion's and Honda's charts and our calculator, unless noted.

Tips to get the most from 3,500 watts

• Start the biggest motor first. Then add the rest one at a time.
• Don't stack heat makers. A microwave, coffee maker, hair dryer or space heater each use 1,000–1,500 W.
• Let the fridge and AC share. They'll cycle on and off; the generator only has to catch one surge at a time.
• Watch the altitude. Generators lose about 3.5% per 1,000 feet, so a 3,500 W unit at 5,000 feet acts closer to 2,900 W.

Check your own appliances

Look for the label on each appliance. Amps × 120 = running watts. For motors, look for "LRA" or plan on two to three times the running watts to start. Then add them up in our calculator.

Safety: Run it outdoors only, 20+ feet from the house, away from windows and doors. Read our carbon monoxide guide.