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Generator Wattage Chart: Running and Starting Watts for Home Appliances
To size a generator, add up the running watts of everything you want on at once, then add the single biggest extra starting surge. The chart below lists running and starting watts for common household appliances from two generator makers, Honda and Champion. Use it to estimate, then confirm with the labels on your own appliances.
Generator wattage chart: household appliances
| Appliance | Honda running / starting | Champion running / starting |
|---|---|---|
| Refrigerator | 132 to 192 / 1,200 | 150 to 400 / 800 to 1,200 |
| Freezer | 132 to 192 / 1,200 (same row as fridge) | 100 to 500 / 500 to 1,000 |
| Furnace fan, 1/2 HP | 875 / 2,350 | 300 to 800 / 800 to 1,600 |
| Furnace fan, 1/3 HP | 700 / 1,400 | Not listed |
| Sump pump, 1/3 HP | 800 / 1,300 | 500 to 800 / 1,000 to 1,600 |
| Sump pump, 1/2 HP | 1,050 / 2,150 | 800 to 1,050 / 1,300 to 2,150 |
| Well pump, 1/2 HP | Not listed | 750 to 1,000 / 1,500 to 2,000 |
| Well pump, 1 HP | Not listed | 1,000 to 2,000 / 2,000 to 4,000 |
| Window AC, 10,000 BTU | 1,500 / 2,200 | 900 to 1,200 / 1,800 to 2,400 |
| Window AC, 5,000 BTU | Not listed | 450 to 600 / 900 to 1,200 |
| Central AC, 3 ton | Not listed | 3,000 to 3,500 / 5,000 to 6,000 |
| Electric water heater | 4,500 / 4,500 | 3,000 to 4,500 / none extra |
| Washing machine | 1,200 / 1,200 | 500 to 1,000 / 1,000 to 2,300 |
| Electric dryer | 5,400 / 6,750 | 4,000 to 6,000 / none extra |
| Dishwasher | 216 / 540 (cool dry) | 1,200 to 2,400 / none extra |
| Microwave, 1,000 W | 1,500 / 1,500 | 600 to 1,200 / none extra (any size) |
| Electric range | 2,100 / 2,100 (one 8 inch element) | 1,200 to 2,400 / none extra (one burner) |
| Coffee maker, 4 cup | 600 / 600 | Not listed |
| Space heater | 1,300 / 1,300 (radiant) | 750 to 1,500 / none extra |
| TV | 120 (20 inch) to 190 (46 inch) | 80 to 400 (32 to 55 inch) |
| Lights | As marked on the bulb | 8 to 15 per LED bulb |
| Ceiling fan | Not listed | 15 to 75 |
| Laptop | 200 to 250 | 20 to 100 (phone or laptop charger) |
| Desktop computer | 600 to 800 | Not listed |
| Internet router and modem | Not listed | 10 to 20 |
| CPAP | Not listed | 30 to 60 (60 to 120 with heated humidifier) |
| Garage door opener | 720 / 1,420 | Not listed |
| Home security system | Not listed | 15 to 40 |
Sources: Honda Power Equipment, "What wattage generator do I need?" guide; Champion Power Equipment generator wattage chart (April 2026). Where only one number is shown, starting and running watts are the same. Champion marks heating and electronic loads as needing no extra starting watts. Honda marks the furnace fan, sump pump, water heater, dryer, and range rows as 240V in its guide; many furnace fans and sump pumps run on 120V, so check your label.
Why the two charts disagree
Each chart is an estimate. Champion gives wide ranges to cover many models, while Honda lists a typical value. Some of the gaps are large: Honda lists a laptop at 200 to 250 watts, while Apple ships today's MacBooks with 35 to 140 watt adapters. Your appliance's label or spec sheet beats both charts.
How to calculate generator size
- List what must run at the same time. Skip what you can take turns with.
- Add the running watts.
- Find the one item with the biggest extra starting surge (starting watts minus running watts) and add that once. Briggs and Stratton recommends selecting the one item with the highest additional starting watts.
- Pick a generator whose running watts beat step 2 and whose starting watts beat step 3, with some margin.
Champion's own worksheet adds the highest single starting watt to total running watts, a slightly more conservative version of the same idea. If an appliance lists only amps, Generac's worksheet says to multiply amps by 120 volts to get watts.
Worked example (Honda figures)
| Load | Running | Extra starting |
|---|---|---|
| Refrigerator | 192 | 1,008 |
| Furnace fan, 1/2 HP | 875 | 1,475 |
| Sump pump, 1/2 HP | 1,050 | 1,100 |
| Microwave, 1,000 W | 1,500 | 0 |
| TV, 46 inch | 190 | 0 |
| Garage door opener | 720 | 700 |
| Total | 4,527 | Biggest single: 1,475 |
Peak = 4,527 + 1,475 = 6,002 watts. That calls for at least about 4,600 running and 6,000 starting watts, so a 4,500 running watt generator is just short. Skip the microwave while the garage door runs, or step up to a 6,500 to 7,600 running watt model.
Match your total to a generator
| Your running total | Generator | Starting / running watts | Price |
|---|---|---|---|
| Up to about 4,000 W | DuroMax XP5500HX | 5,500 / 4,500 | $629 |
| Up to about 6,000 W | DuroStar DS8000iX | 8,000 / 6,500 | $999 |
| Up to about 6,500 W | DuroMax XP8500EH | 8,500 / 7,000 | $1,075.99 |
| Up to about 7,000 W, inverter power | DuroMax XP9500iH | 9,500 / 7,600 | $1,999 |
| Up to about 10,000 W | DuroMax XP13000EH | 13,000 / 10,500 | $1,299 |
| Up to about 11,500 W | DuroMax XP15500HX | 15,500 / 12,000 | $2,299 |
Running and starting watts are gasoline ratings from each product page. The "your running total" column is our suggestion, leaving roughly 10% headroom. For whole-house planning, read What Size Generator Do You Need to Run a House?, or see What Will a 5,000 Watt Generator Run? and What Will a 3,500 Watt Generator Run?
Want us to check your list? Call 1-888-855-7286. Send the running and starting watts from your appliance labels, and we will size the generator and hookup for you.
Generator wattage FAQ
How do I calculate what size generator I need? Add the running watts of everything that runs at once, then add the biggest single extra starting surge.
What is the difference between running and starting watts? Running watts are continuous power. Starting watts are a short burst motors need to start, which Briggs and Stratton describes as lasting two to three seconds.
How many watts does a refrigerator need on a generator? 132 to 192 running and 1,200 starting watts per Honda, or 150 to 400 running and 800 to 1,200 starting per Champion.
Do heaters and microwaves need starting watts? Champion's chart lists no extra starting watts for space heaters, microwaves, water heaters, and electronics.
What if my appliance only lists amps? Multiply amps by 120 volts for a 120V appliance, per Generac's worksheet.