Generator Wattage Chart

How to Use This Wattage Chart for Generator Sizing

This chart gives you the running and surge wattage for every common household appliance. Here's how to use it to size your generator:

1. Find each appliance you want to power in the chart above.
2. Note the running watts for each appliance.
3. For motor-driven appliances (AC units, pumps, compressors), note the surge watts.
4. Add all running watts together — this is your total continuous load.
5. Find the single appliance with the highest surge watts.
6. Divide total running watts by 0.8 to get your minimum generator running wattage.
7. Verify your chosen generator's starting watts exceed the highest surge load.

Or simply use our generator size calculator to do all of this automatically.

Why Surge Watts Matter More Than Running Watts

Most people focus on running watts when sizing a generator, but surge (starting) watts are often the real limiting factor. A common scenario: you buy a 3,500-watt generator, hook up your refrigerator and sump pump, and the generator immediately shuts down on overload.

What happened? Your refrigerator and sump pump together might only draw 950 watts continuously — well within the 3,500-watt rating. But if the sump pump motor tried to start while the refrigerator compressor was also starting, the combined surge could hit 4,500–5,000 watts, tripping the generator's overload protection.

The solution is twofold: (1) Size your generator with surge headroom — don't plan to run at 100% continuous load. (2) Stagger the startup of large motors — don't start the refrigerator and AC unit simultaneously. Modern smart generators can handle some load sequencing, but manual awareness is important.

Surge Multiplier Explained

The surge multiplier column in the chart above shows how many times the running watts a motor needs to start. Here's what the colors mean:

• 3.5–4× (Red): Very high surge load. Central AC units, air compressors, and heavy pumps. Requires significant generator headroom above running load.
• 2.5–3.5× (Orange): High surge. Refrigerators, window AC units, sump pumps. Must be accounted for in generator sizing.
• 1.1–2.5× (Yellow): Moderate surge. Some power tools, smaller motors. Typically manageable with normal safety margins.
• 1× (Gray): No meaningful surge. Resistive loads like heaters, lights, and most electronics. Size purely on running watts.