The most common generator question I hear is “what can I actually power with this thing?” The answer lives in two numbers: running watts and starting watts. Every appliance has a running wattage (the power it needs to operate continuously) and many have a starting wattage (the brief power surge needed to start motors and compressors). Understanding these numbers is the difference between a generator that handles your needs and one that trips its breaker every time the fridge kicks on.
This guide provides real-world wattage data for common household appliances and shows you exactly what different generator sizes can handle.
Understanding Running Watts vs Starting Watts
Running Watts (Continuous Watts)
Running watts is the continuous power an appliance draws during normal operation. A 100W light bulb draws 100 running watts. A refrigerator draws 100-200 running watts while the compressor is cycling. This is the steady-state power consumption you’ll see on the appliance’s nameplate or in its manual.
Starting Watts (Surge Watts)
Starting watts is the brief power spike that motor-driven appliances need to start up. Electric motors draw 2-3x their running wattage for a fraction of a second (typically 0.5-3 seconds) when they first turn on. A refrigerator that runs at 150W may need 1,200W to start its compressor. An air conditioner running at 1,500W may need 4,500W to start. Your generator must be able to handle the highest single starting surge while also powering everything else that’s already running.
How to Read Your Generator’s Rating
Generators are rated with two numbers: running watts and starting (peak/surge) watts. A “5,000/6,250W” generator delivers 5,000 watts continuously and can handle a 6,250W surge for starting motors. The running watts number is your budget for total continuous load. The starting watts number is your budget for the highest single startup surge plus all running loads.
Complete Appliance Wattage Chart
Kitchen Appliances
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Refrigerator (standard) | 100-200 | 800-1,200 |
| Refrigerator (large side-by-side) | 150-250 | 1,000-1,500 |
| Chest Freezer | 50-100 | 500-1,000 |
| Microwave (1,000W) | 1,000-1,500 | 1,000-1,500 |
| Coffee Maker | 600-1,200 | 600-1,200 |
| Toaster (2-slice) | 800-1,200 | 800-1,200 |
| Electric Kettle | 1,200-1,500 | 1,200-1,500 |
| Blender | 300-700 | 600-1,400 |
| Slow Cooker | 150-300 | 150-300 |
| Instant Pot | 700-1,000 | 700-1,000 |
| Dishwasher | 1,200-1,800 | 1,400-2,200 |
| Electric Stove (single burner) | 1,500-2,500 | 1,500-2,500 |
| Electric Oven | 2,000-5,000 | 2,000-5,000 |
Note: Heating appliances (toasters, kettles, coffee makers, ovens) don’t have starting surges because they use resistive heating elements, not motors. Their running watts equal their starting watts.
Heating and Cooling
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Window AC (5,000 BTU) | 400-600 | 1,200-1,800 |
| Window AC (8,000 BTU) | 700-1,000 | 2,100-3,000 |
| Window AC (12,000 BTU) | 1,000-1,400 | 3,000-4,200 |
| Portable AC (8,000-12,000 BTU) | 900-1,400 | 2,700-4,200 |
| Central AC (2-ton) | 2,500-3,000 | 5,000-7,000 |
| Central AC (3-ton) | 3,000-3,800 | 6,000-9,000 |
| Central AC (5-ton) | 5,000-6,000 | 10,000-15,000 |
| Furnace Fan (gas furnace) | 500-800 | 1,000-1,600 |
| Space Heater (electric) | 750-1,500 | 750-1,500 |
| Portable Fan | 50-120 | 50-120 |
| Ceiling Fan | 60-120 | 60-120 |
Water and Plumbing
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Sump Pump (1/3 HP) | 600-800 | 1,200-1,800 |
| Sump Pump (1/2 HP) | 800-1,050 | 1,800-2,400 |
| Well Pump (1/2 HP) | 750-1,000 | 1,500-2,400 |
| Well Pump (1 HP) | 1,500-2,000 | 3,000-4,500 |
| Electric Water Heater (40-50 gal) | 4,000-5,500 | 4,000-5,500 |
| Tankless Water Heater (electric) | 8,000-18,000 | 8,000-18,000 |
Lighting and Electronics
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| LED Light Bulb (60W equivalent) | 8-12 | 8-12 |
| CFL Light Bulb (60W equivalent) | 13-15 | 13-15 |
| Incandescent Light Bulb (60W) | 60 | 60 |
| LED TV (55″) | 60-100 | 60-100 |
| Desktop Computer + Monitor | 200-500 | 200-500 |
| Laptop | 30-100 | 30-100 |
| WiFi Router | 10-20 | 10-20 |
| Cable/Satellite Box | 20-35 | 20-35 |
| Phone Charger | 5-20 | 5-20 |
| Gaming Console | 100-200 | 100-200 |
Laundry
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Washing Machine | 400-600 | 1,200-1,800 |
| Electric Dryer | 2,000-5,000 | 2,000-6,000 |
| Gas Dryer (electric ignition) | 300-600 | 600-1,200 |
Power Tools
| Tool | Running Watts | Starting Watts |
|---|---|---|
| Circular Saw | 1,200-1,800 | 2,400-3,600 |
| Miter Saw (10″) | 1,200-1,800 | 2,400-3,600 |
| Table Saw | 1,500-2,000 | 3,000-4,500 |
| Drill (1/2″) | 500-900 | 500-1,200 |
| Air Compressor (1 HP) | 1,000-1,500 | 3,000-4,500 |
| Shop Vacuum | 600-1,400 | 1,200-2,800 |
What Can Each Generator Size Power?
2,000W Generator
A 2,000W inverter generator handles basic essentials for one or two people:
Cannot power: window AC, microwave, space heater, power tools, sump pump
3,500W Generator
A 3,500W generator adds small comfort appliances:
Load management required — can’t run AC and microwave at the same time
5,000W Generator
A 5,000W generator is the sweet spot for most homes during outages:
Can also handle a microwave or coffee maker one at a time, but not while the sump pump is starting
7,500W Generator
A 7,500W generator adds well pumps and window AC:
10,000W+ Generator
A 10,000W generator handles most home circuits except central AC and electric heating:
14,000W+ (Standby Generator Territory)
At 14,000W and above, you’re in standby generator territory:
How to Calculate Your Total Wattage Needs
Follow this process to determine what generator size you need:
- List every appliance you want to power during an outage
- Find the running watts for each (check the nameplate, manual, or use the charts above)
- Add up all running watts — this is your continuous load
- Identify the appliance with the highest starting watts
- Add that starting wattage to your continuous load total
- Add 20-30% buffer for safety margin
- The result is your minimum generator size
Example calculation:
| Appliance | Running W | Starting W |
|---|---|---|
| Refrigerator | 150 | 1,200 |
| Sump Pump | 800 | 2,150 |
| Furnace Fan | 700 | 1,400 |
| LED Lights (8) | 80 | 80 |
| WiFi Router | 15 | 15 |
| TV | 80 | 80 |
| Phone Charging | 20 | 20 |
Total running watts: 1,845W. Highest starting surge: 2,150W (sump pump). Combined: 1,845 + 2,150 = 3,995W. With 25% buffer: ~5,000W generator recommended.
Tips for Staying Within Your Generator’s Capacity
Frequently Asked Questions
Q: Where do I find my appliance’s wattage?
Check the nameplate sticker on the back or bottom of the appliance — it lists watts, amps, and volts. If it only shows amps, multiply by voltage: Amps × 120V = Watts (for standard outlets) or Amps × 240V = Watts (for large appliances like dryers and AC units). You can also use a plug-in watt meter like the Kill-A-Watt ($20-30) to measure actual power consumption, which is often lower than the nameplate maximum.
Q: Can I run a central AC on a portable generator?
A small central AC (2-ton) requires approximately 2,500-3,000 running watts and 5,000-7,000 starting watts. You’d need at least a 7,500-10,000W generator, and you’d have limited capacity for other appliances. A 3-ton or larger central AC is impractical on a portable generator — it requires a standby generator (14kW+) or a very large portable unit. Window AC units are a much more practical option for portable generator cooling.
Q: What happens if I overload my generator?
Most generators have built-in overload protection — a circuit breaker that trips when the load exceeds the rated capacity. The generator shuts off, protecting itself and your appliances. Reset the breaker, reduce your load, and restart. Repeatedly overloading a generator without tripping the breaker (running at 90-100% continuously) causes overheating, voltage fluctuations, and premature wear on the engine and alternator.
The Bottom Line
For most homes, a 5,000-7,500W generator covers essential circuits during an outage: refrigerator, sump pump, furnace fan, lights, and basic electronics. Adding window AC or a well pump pushes the requirement to 7,500-10,000W. Whole-house coverage including central AC requires 14,000W+ or a standby generator. Use the wattage charts above to calculate your specific needs, add a 20-30% buffer, and buy accordingly.
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