What will a 10,000 watt generator run?

A 10,000 watt generator is near the top of the portable range. It's the size people look at when they want central air, a well pump and the essentials all at once. Here's what it can really do.

First, which 10,000 is it?

Two ratings matter:

• Starting (peak) watts: the short burst for starting motors.
• Running (rated) watts: what it can give all day.

Model names mix them up. Westinghouse's WGen9500DFc is named for its running watts: 9,500 running and 12,500 peak on gas. DuroMax's XP13000EH is named for its peak: 13,000 peak and 10,500 running. So check the spec sheet.

Below, we assume the tougher case: 8,000 running and 10,000 starting watts. If yours is 10,000 running, you have 25% more room.

Will a 10,000 watt generator run a house?

It runs a lot of one, but usually not all of it at once. Using our calculator's figures:

What you run	Running W	Starting W	On 8,000 / 10,000
Essentials: fridge, 1/2 HP sump, furnace fan, lights, Wi-Fi, chargers, TV	2,445	3,595	Yes, easily
Essentials + 3-ton central AC	5,945	8,445	Yes
Essentials + 3-ton central AC + 1/2 HP well pump	6,945	9,445	Yes, just
Essentials + electric water heater + well pump	7,945	9,945	Yes, just
Essentials + 4-ton central AC	7,445	10,445	No, unless the AC has a soft start
Essentials + 3-ton AC + electric water heater	10,445	12,945	No

The central AC rows use the top of Champion's ranges (3 ton: 3,500 running, 6,000 starting; 4 ton: 5,000 running, 8,000 starting). "Just" means it fits with less than our usual 20% headroom.

A worked example: central air, a well pump and the essentials

The calculator above is set up for this:

• Running: 2,445 (essentials) + 1,000 (well pump) + 3,500 (3-ton AC) = 6,945 W
• Biggest surge: the AC, 6,000 − 3,500 = 2,500 W
• Starting: 6,945 + 2,500 = 9,445 W
• With 20% headroom: about 8,350 running and 11,350 starting watts

It fits an 8,000 / 10,000 unit if the pump and the AC don't start at the same moment. A unit rated about 10,000 running watts handles it with room to spare.

Will a 10,000 watt generator run central air?

Central AC	Running W	Starting W	Verdict
2 ton	2,000–2,500	3,500–4,500	Yes, with plenty of the house
3 ton	3,000–3,500	5,000–6,000	Yes, with the essentials
4 ton	4,000–5,000	6,500–8,000	Alone, or with a soft start
5 ton	Bigger still	Often too much	Needs a soft start, and maybe more

Figures for 2–4 tons are from Champion's chart. Honda's chart gives 6,000 running and 7,800 starting watts for a 40,000 BTU (about 3.3 ton) central AC, so charts vary a lot. The AC's own label is the best guide.

On Micro-Air's page for its home soft starter, one customer reports a 5-ton AC that would not start on a 13 kW generator until a soft starter was fitted. That's one owner's report, not a test. See will a generator run central air?

Will it run a heat pump?

A ducted heat pump is like a central AC that also runs in reverse to heat, so the compressor is sized the same way. The catch is the backup electric heat (often labeled "aux" or "emergency heat") in the indoor unit. It's rated in kilowatts. If it switches on while you're on the generator, it can overload it. Ask your electrician or HVAC tech how to keep it off during an outage. More in the central air and heat pump guide.

You need a 50 amp hookup to use it all

How the generator connects to the house caps what it can deliver:

Outlet and cord	Most it can carry
L14-30 (30 A, 120/240 V)	7,200 W
14-50 (50 A, 120/240 V)	12,000 W

A 10,000 W generator on a 30 amp inlet can only send 7,200 W. The WGen9500DFc and XP13000EH both have a 14-50R outlet as well as an L14-30R. For full output, have a licensed electrician fit a 50 A inlet and transfer switch or interlock. See how to connect a generator to a house and 30 amp vs 50 amp generator cords.

More "will it run" answers

Appliance	On a 10,000 W generator
50 amp RV with 2 or 3 ACs	Yes. Three 13,500 BTU ACs plus the basics is about 6,230 running and 7,730 starting
Electric water heater (4,500 W, 240 V)	Yes, with the essentials. Not with central air too
Electric dryer (4,000–6,000 W)	Yes, but it uses most of the spare power
Well pump, 1–1.5 HP	Yes. Franklin Electric's minimums go up to 7,500 W for a 1.5 HP 2-wire pump
240 V welder	Most. Champion lists 3,000–8,000 running
Air compressor, 3 HP	Borderline. Champion lists 3,500 running and 10,500 starting

Propane, altitude and heat

• Propane: the WGen9500DFc makes 8,500 running watts on propane, down from 9,500 on gas.
• Altitude and heat: Westinghouse's manual says power drops about 3.5% per 1,000 feet above sea level, and about 1% per 10°F above 60°F.

Check your own home

• Central AC: the outdoor unit's label shows BTU or tons, and often "LRA" (the start-up current). A high LRA means a hard start.
• Other big loads: the label gives watts or amps. For 240 V items, amps × 240 = watts.

Then add it all up in the calculator above.

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