How Many Watts Do You Need to Run Your House?

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The short answer

To run the essentials during an outage (refrigerator, freezer, lights, internet, phone chargers and a gas furnace blower), most homes need about 3,000 to 7,500 running watts. To run nearly everything, including central air, a 240V well pump or an electric range, plan on 10,000 watts or more. The exact number comes from adding the running watts of what you will use at the same time, then adding the single biggest starting surge.

Running watts vs starting watts

Every generator lists two numbers. Running (rated) watts are what it can deliver continuously. Starting (peak or surge) watts are what it can deliver for a few seconds while a motor spins up. Refrigerators, freezers, sump pumps, well pumps and air conditioners all have compressors or motors that briefly pull two to three times their running draw. For example, the Westinghouse WGen9500DF is rated 9,500 running and 12,500 peak watts on gasoline; the Honda EU2200i is 1,800 rated and 2,200 max.

For battery power stations, the equivalents are continuous output and surge, plus a third number that matters just as much: capacity in watt-hours (Wh), which tells you how long the battery lasts.

Typical appliance wattage

These are common approximate ranges. Your appliances may differ, so always check the nameplate (amps × volts = watts) or measure with a plug-in watt meter.

Appliance	Approx. running watts	Starting surge?	Priority in an outage
Refrigerator	About 100–800	Yes, compressor	Essential
Chest or upright freezer	About 100–500	Yes, compressor	Essential
Sump pump (1/2 hp)	About 800–1,050	Yes, high	Essential if you have one
Well pump (240V)	About 1,000–2,000+	Yes, very high	Essential on well water
Gas furnace blower	About 300–900	Yes	Essential in winter
LED lights (several rooms)	About 50–200 total	No	Essential
Wi-Fi router and modem	About 10–30	No	Essential
TV	About 50–200	No	Nice to have
Microwave	About 800–1,500	No	Short bursts
Coffee maker	About 600–1,200	No	Short bursts
Window AC unit	About 500–1,500	Yes	Comfort
Space heater	Up to 1,500	No	Avoid on small units
Electric water heater (240V)	About 4,000–5,500	No	Usually skipped
Electric range or oven (240V)	Several thousand	No	Large units only
Central AC (3–4 ton)	Several thousand	Yes, very high	Check nameplate and ask an HVAC pro

How to calculate your number in four steps

• 1. List what must run at the same time. Be honest: in an outage you can run the microwave, then the coffee maker, not both at once.
• 2. Add their running watts. Fridge 700 + freezer 400 + furnace blower 600 + lights 150 + router 25 + TV 150 = about 2,025 running watts.
• 3. Add the single largest starting surge. Only one motor usually starts at a time. If the fridge surges to roughly 2,000W, add the difference (about 1,300W) to get about 3,300 watts of starting capacity needed.
• 4. Add a 20–25% buffer. Generators run happier and quieter below full load. In this example, a unit with about 4,000+ running watts gives comfortable headroom.

Three common household scenarios

Scenario	What runs	Approx. running watts	What fits
Bare essentials	Fridge, router, phones, a few lights	About 1,000–2,000	Inverter generator like the Honda EU2200i, or a power station like the Jackery Explorer 2000 Plus
Comfortable essentials	Above plus freezer, furnace blower, sump pump, TV, microwave in bursts	About 3,000–7,500	Mid-to-large portable generator, or a large power station such as the Anker SOLIX F3800
Most of the house	Above plus 240V well pump, central AC, electric cooking or dryer	10,000+	Large dual-fuel generator like the Westinghouse WGen9500DF through a transfer switch, or a home standby generator

Generators and power stations by size

We compared spec sheets, owner reviews and published reviews. These cover the three scenarios above.

Pick	Model	Output	Best for	Amazon
Small and quiet	Honda EU2200i	1,800W rated / 2,200W max; 0.95-gal tank	Bare essentials	Check price
Indoor battery	Jackery Explorer 2000 Plus	3,000W continuous / 6,000W surge; 2,042Wh	Bare essentials, no fumes	Check price
Large battery, 240V	Anker SOLIX F3800	6,000W continuous; 3,840Wh; 120/240V	Comfortable essentials, well pumps	Check price
Tri-fuel generator	Champion 9,000-Watt Tri-Fuel Inverter	9,000W starting; 7,250W running on gas, 6,525W propane, 5,875W natural gas	Comfortable essentials with fuel flexibility	Check price
Big dual-fuel	Westinghouse WGen9500DF	9,500W running / 12,500W peak (gas); 8,500W running on propane	Most of the house via transfer switch	Check price

Honda EU2200i

Honda’s spec sheet lists 1,800 rated watts, 2,200 max, a 0.95-gallon tank good for 8.1 hours at quarter load, and 53 dB at quarter load. It is about 46.5 lb dry, so one person can carry it. Good to know: it will not run a 240V well pump or central air. Check the Honda EU2200i on Amazon

Jackery Explorer 2000 Plus

A 2,042Wh LiFePO4 power station with 3,000W continuous and 6,000W surge output, expandable to roughly 12kWh with add-on battery packs. It recharges from the wall in about 2 hours. Good to know: a single unit is 120V only; 240V requires pairing two units. Check the Jackery Explorer 2000 Plus on Amazon

Anker SOLIX F3800

6,000W continuous at 120V or 240V from 3,840Wh of LFP battery, expandable to 53.8kWh, with up to 2,400W of solar input. Good to know: 240V output is not available while charging from 120V AC. Check the Anker SOLIX F3800 on Amazon

Champion 9,000-Watt Tri-Fuel Inverter

Runs on gasoline, propane or natural gas: 7,250 running watts on gas, 6,525 on propane, 5,875 on natural gas, with 9,000 starting watts on all fuels, a 4.3-gallon tank and up to 14 hours of runtime. Good to know: output drops on propane and natural gas, so size for the fuel you will actually use. Check the Champion Tri-Fuel on Amazon

Westinghouse WGen9500DF

9,500 running and 12,500 peak watts on gasoline, 8,500 running on propane, with a 6.6-gallon tank, remote key-fob start, and both an L14-30R and a 14-50R outlet for transfer-switch connection. Good to know: it weighs about 211 lb dry and is loud; one review measured roughly 89–90 dB at 6 feet. Check the Westinghouse WGen9500DF on Amazon

Sizing a power station: watt-hours matter too

A power station must cover both your peak load (watts) and your total use (watt-hours). Multiply each item’s average watts by hours used, then add them up. A fridge that averages about 150W over a day (because the compressor cycles) uses about 3,600Wh in 24 hours, more than a 2,042Wh unit holds. That’s why many owners add solar panels or expansion batteries, or recharge from a small generator.

Safety and installation

• Run gas generators outdoors only, far from doors, windows and vents. Never in a garage, even with the door open. Keep CO alarms working inside.
• Connect to house circuits only through a transfer switch or interlock installed by a licensed electrician. Never backfeed through a dryer outlet.
• Use heavy-gauge outdoor extension cords sized for the load.
• Do not exceed running-watt ratings; overloads trip breakers and stress the engine or inverter.

FAQ

How many watts does it take to run a house?

For essentials only (fridge, lights, internet, a furnace fan, sump pump), many homes need roughly 3,000–7,500 running watts. To run most of a house including central air, an electric range or a well pump, you are often looking at 10,000 watts or more, which points toward a large portable generator with a transfer switch or a standby generator.

Will a 2,200-watt generator run a refrigerator?

Usually yes, on its own. The Honda EU2200i is rated 1,800W running and 2,200W max, which typically covers a fridge’s startup surge. Avoid starting other large motors at the same time.

What size generator do I need to run central air?

It depends on the AC’s tonnage and starting current. Check the condenser’s nameplate for running amps and locked-rotor amps, and talk to an HVAC tech or electrician. Large portable generators in the 9,000–10,000 running-watt class can run some systems, especially with a soft-start kit, but not all.

What’s the difference between running watts and starting watts?

Running watts are what an appliance draws continuously. Starting (surge) watts are the brief spike when a motor or compressor kicks on, often two to three times higher. Size your generator so total running watts fit, plus the single largest starting surge.

How do I find an appliance’s actual wattage?

Look at its nameplate or manual. If it lists amps, multiply amps by volts (for example, 5 A × 120 V = 600 W). For plug-in items, an inexpensive plug-in watt meter gives the real draw.