Essentials
| Appliance | Running watts | Starting watts | Volts |
|---|
| Refrigerator (modern, Energy Star) | 150 | 1,200 | 120 |
| Refrigerator (older than ~2005) | 700 | 2,200 | 120 |
| Chest freezer | 100 | 800 | 120 |
| Upright freezer | 150 | 1,000 | 120 |
| LED lights (10 bulbs) | 100 | 100 | 120 |
| Wi-Fi router + modem | 20 | 20 | 120 |
| Phone chargers (2) | 20 | 20 | 120 |
| Ceiling fan | 75 | 75 | 120 |
| Box fan | 100 | 100 | 120 |
| Sump pump (1/3 HP) | 800 | 1,300 | 120 |
| Sump pump (1/2 HP) | 1,050 | 2,150 | 120 |
Heating & cooling
| Appliance | Running watts | Starting watts | Volts |
|---|
| Furnace blower fan (gas furnace, 1/2 HP) | 875 | 2,350 | 120 |
| Window AC (5,000 BTU) | 500 | 1,500 | 120 |
| Window AC (8,000 BTU) | 900 | 2,700 | 120 |
| Window AC (12,000 BTU) | 1,400 | 4,200 | 120 |
| Central AC (2 ton) | 2,800 | 8,000 | 240 |
| Central AC (3 ton) | 3,500 | 9,800 | 240 |
| Heat pump (3 ton) | 4,700 | 9,400 | 240 |
| Space heater | 1,500 | 1,500 | 120 |
| Dehumidifier (50 pint) | 650 | 1,000 | 120 |
| Electric blanket | 100 | 100 | 120 |
Kitchen
| Appliance | Running watts | Starting watts | Volts |
|---|
| Microwave (1,000 W cooking power) | 1,500 | 1,500 | 120 |
| Coffee maker | 1,000 | 1,000 | 120 |
| Electric kettle | 1,500 | 1,500 | 120 |
| Air fryer | 1,500 | 1,500 | 120 |
| Slow cooker | 250 | 250 | 120 |
| Toaster | 1,000 | 1,000 | 120 |
| Blender | 400 | 800 | 120 |
| Electric stove (one burner, 240 V range) | 1,500 | 1,500 | 240 |
| Dishwasher (with heated dry) | 1,500 | 1,500 | 120 |
Water & laundry
| Appliance | Running watts | Starting watts | Volts |
|---|
| Well pump (1/2 HP) | 1,000 | 2,100 | 240 |
| Well pump (3/4 HP) | 1,500 | 3,200 | 240 |
| Washing machine | 1,150 | 2,250 | 120 |
| Gas dryer (motor only) | 700 | 1,800 | 120 |
| Electric dryer | 5,400 | 6,750 | 240 |
| Electric water heater (tank) | 4,500 | 4,500 | 240 |
Electronics & medical
| Appliance | Running watts | Starting watts | Volts |
|---|
| TV (50" LED) | 100 | 100 | 120 |
| Laptop | 60 | 60 | 120 |
| Desktop computer + monitor | 250 | 250 | 120 |
| CPAP (no humidifier) | 40 | 40 | 120 |
| CPAP with heated humidifier | 90 | 90 | 120 |
| Home oxygen concentrator (5 L) | 350 | 700 | 120 |
| Game console | 150 | 150 | 120 |
Garage & tools
| Appliance | Running watts | Starting watts | Volts |
|---|
| Garage door opener (1/2 HP) | 875 | 2,350 | 120 |
| Power drill | 600 | 900 | 120 |
| Circular saw (7¼") | 1,400 | 2,300 | 120 |
| Air compressor (1 HP) | 1,600 | 4,500 | 120 |
| EV charger (Level 1) | 1,440 | 1,440 | 120 |
RV
| Appliance | Running watts | Starting watts | Volts |
|---|
| RV air conditioner (13,500 BTU) | 1,300 | 2,750 | 120 |
| RV air conditioner (15,000 BTU) | 1,500 | 3,500 | 120 |
| RV fridge (electric mode) | 300 | 300 | 120 |
| RV converter / battery charger | 300 | 300 | 120 |
How to use this chart
- Pick everything you want to run at the same time and add their running watts.
- Find the single appliance with the biggest difference between starting and running watts, and add that difference once.
- Add 20% as a safety margin. That's the running wattage your generator should have.
Or skip the math: use the planner, which also tells you how long a battery power station would last and which models fit.
Frequently asked questions
How do I find the wattage of an appliance?
Look for the label or nameplate, usually on the back or bottom. If it lists watts, use that number. If it lists volts and amps, multiply them: 120 volts × 5 amps = 600 watts. For motors, the starting watts are often 2 to 3 times the running watts.
Why do some appliances have higher starting watts?
Anything with an electric motor or compressor (refrigerators, freezers, pumps, air conditioners, washers) needs a short burst of extra power to start spinning. Heaters, lights and electronics start at the same wattage they run at.
How many watts does a refrigerator use on a generator?
A modern ENERGY STAR refrigerator runs on about 150 to 200 watts and needs about 1,200 watts for a moment to start. Older refrigerators can run on 700 watts and need 2,000+ watts to start. Because the compressor cycles on and off, the fridge only draws power about 40% of the time.
Typical values from generator manufacturers' wattage guides and ENERGY STAR data. Your appliance may differ: the label on it is always the final word.