What will a 7,500 watt generator run?

A 7,500 watt generator is the size many people pick for home backup. It has a 240 V outlet, it can power a transfer switch, and it can take on a well pump or a small central AC. Here's what fits.

First, which 7,500 is it?

Generators have two ratings:

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

The number in a model's name can be either. Westinghouse's WGen7500DFc is named for its running watts: 7,500 running and 9,500 peak on gas. Other models use the peak figure, with about 6,000 running. Check the spec sheet.

Below, we show both: a tougher 6,000 running / 7,500 starting case, and a 7,500 running / 9,500 starting case.

Will a 7,500 watt generator run a house?

It runs the essentials plus one or two big loads. Using our calculator's figures:

What you run	Running W	Starting W	6,000 / 7,500	7,500 / 9,500
Essentials: fridge, 1/2 HP sump, furnace fan, lights, Wi-Fi, chargers, TV	2,445	3,595	Yes	Yes
Essentials + well pump (1/2 HP), freezer, microwave	4,745	6,745	Yes	Yes
Essentials + 2-ton central AC	4,945	6,945	Yes, just	Yes
Essentials + 3-ton central AC	5,945	8,445	No	Yes, just
Essentials + electric water heater (4,500 W)	6,945	8,095	No	Yes, just

Central AC figures are from Champion's chart, using the top of each range (2 ton: 2,500 running, 4,500 starting; 3 ton: 3,500 running, 6,000 starting). The well pump uses 3,000 starting watts, Franklin Electric's minimum for a 1/2 HP 2-wire pump.

"Just" means it fits, but with less than our usual 20% headroom. Switch off one item before the AC or pump starts, and it's comfortable.

A worked example: essentials and a 2-ton central AC

The calculator above is set up for this:

• Running: 2,445 (essentials) + 2,500 (AC) = 4,945 W
• Biggest surge: the AC, 4,500 − 2,500 = 2,000 W
• Starting: 4,945 + 2,000 = 6,945 W
• With 20% headroom: about 5,950 running and 8,350 starting watts

That's under 7,500 starting, so it fits the tougher case. A unit rated 7,500 running handles it with room to spare.

Will a 7,500 watt generator run central air?

Central AC	Running W	Starting W	Verdict
2 ton	2,000–2,500	3,500–4,500	Yes, with the essentials
3 ton	3,000–3,500	5,000–6,000	Yes if it's 7,500 running; tight with the essentials
4 ton	4,000–5,000	6,500–8,000	Alone at best. A soft start helps

Most central ACs run on 240 V, so they need the generator's L14-30 outlet and a transfer switch or interlock. A soft start kit cuts the start-up surge; Micro-Air says its home unit is made for this. Full details in will a generator run central air?

The 7,200 W limit of an L14-30 outlet

Most 7,500 W generators have an L14-30R outlet for the transfer switch. It's rated 30 A at 240 V, which is 7,200 W. So even a unit rated 7,500 running can only send 7,200 W through that one outlet. That's fine for most homes. If you need more, you need a bigger generator with a 14-50R outlet and a 50 A inlet. See 30 amp vs 50 amp generator cords.

More "will it run" answers

Appliance	On a 7,500 W generator
50 amp RV with two 13,500 BTU ACs	Yes. About 4,730 running and 6,230 starting with the basics. See generator for a 50 amp RV
Well pump, 1 HP	Yes. Franklin says 4,000 W (3-wire) or 6,000 W (2-wire) minimum
Gas furnace	Yes, with lots to spare
Electric water heater (240 V)	Yes, with the fridge and lights; not with central air too
Electric dryer (4,000–6,000 W, Champion)	Maybe, on its own. Not a good use of generator fuel
Electric furnace or heat strips	Check the label. They're rated in kilowatts (kW); 1 kW = 1,000 W
240 V welder	Depends. Champion lists 3,000–8,000 running
Air compressor, 2 HP	Yes, alone. Champion lists 2,500 running and 7,500 starting

Propane, altitude and heat

• Propane: dual-fuel units make less on propane. The WGen7500DFc drops to 6,750 running watts.
• Altitude: generators lose about 3.5% per 1,000 feet above sea level (Westinghouse). At 5,000 feet, 7,500 running watts acts like about 6,200.

How long does a 7,500 watt generator run?

Westinghouse says the WGen7500DFc runs up to 11 hours at 25% load on its 6.6-gallon tank. At higher loads it's less. See how long a generator runs on 5 gallons of gas.

Check your own appliances

Read the label on each one: amps × 120 = watts (amps × 240 for 240 V items). For a central AC, the outdoor unit's label gives its size in BTU or tons. 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.