What Can a 4000 Watt Generator Run? TOP 3 4000 Watt Generators

In this guide, we will cover what can a 4000 watt generator run, the top 3 best 4000 watt generators, the most searched questions about this, and helpful tips.

Due to the growing number of natural disasters and power outages, the sales volume of portable generators has exponentially increased.

A 4000-watt generator is the most popular choice for backup power, camping, and RV because it is not too big, and not too small in terms of size and power. (checkout our buying guide about the portable Rv generators)

Usually, a 4000-watt generator approximately provides 33.4 amps for 120v and 16.7 amps for 240v. In simple terms, it should run the following appliances:

  • Ac unit small – 1000 to 1200 watts
  • Fridge with a freezer – 600 to 700 watts
  • Well pump small – ½ HP 1000 watts
  • Washing machine – 1150 to 1200 watts
  • Microwave oven – 800 to 1000 watts
  • Pressure cooker – 700 to 800 watts
  • Standard dishwasher – 1300 to 1500 watts
  • Toaster – 700 to 850 watts
  • Ceiling fan – 40 to 60 watts
  • Heating system small – 500 to 600 watts
  • Power tools (a couple of small power tools) – 800 to 1000 watts
  • Hammer drill – 800 to 1000 watts
  • Bench grinder – 1300 to 1400 watts
  • Electric water heater – 3500 to 4000 watts
  • Steam iron – 1800 to 2200 watts

Above mentioned appliances and their wattage levels are a rough estimation. Before we break it down, you would need to understand peak/surge watts, and running watts.

What are Starting Watts and Running Watts?

Starting/peak watts: The surge of maximum power the generator can provide for a few seconds to start motor-driven appliances.

Motor-driven appliances need a few extra watts from their original capacity to overcome inertia and start. Later, these appliances settle down to their rated capacity.  

Rated/running watts: The amount of power the generator can provide constantly for hours. Rated or running watts are always less than the starting watts. Not all appliances need an initial push to start.

Before purchasing a generator, check its starting and running watts, then calculate starting and running watts of appliances you need to run.

Sometimes people purchase 4000-watt generators without even knowing the rated and surge watts of devices they need to start and they later complain about the generator.

What Can A 4000 Watt Generator Run?

What Can a 4000 Watt Generator Run

A 4000-watt generator provides enough power to run the following appliances:

ApplianceQuantityPeak wattsRunning watts
A standard fridge11200200
Microwave oven110001000
Coffee maker1600600
AC (10,000) BTU144003000
Electric blanket1200200
Computer1250250
Incandescent lights5300300
Sump Pump18001500 to 300
Well pump110002000

Suppose a generator is rated at 3800 watts, and 4000 peak watts. If you need to run 4 appliances together whose running watts collectively are 3600 watts, and 3900 starting watts, so in theory, your generator should provide enough power to run all four appliances at once.

But, you shouldn’t push it to its peak because not all generators provide as much power as they advertised. So be careful.

Checkout our guide about what can a 3500 watt generator run?

Can A 4000-Watt Generator Run A Central Air Conditioner?

Yes. It can surely run a central AC system of 10,000 BTU.

AC UNITPeak wattsRunning watts
10,000 BTU22001500

Will A 4000 Watt Generator Run Space Heaters?

Absolutely. Normal space heaters take 1750 to 1800 running watts, and 1800 starting watts. You can easily run 2 space heaters if you want. Nowadays, there are even more efficient space heaters in the market.

Will A 4000-Watt Generator Run A Microwave, Fridge?

It should easily run both without any problem. A standard microwave takes about 1000 running watts, a fridge takes 1200 to 1000 surge watts, and 200 running watts (check out our guide about is it safe to run a refrigerator on a generator?).  Run some other low-wattage appliances with these two at a time as well.

Can A 4000 Watt Generator Run A Circular Saw?

YES. A circular saw takes about 1400 running watts, and 2300 starting watts. It will run two circular saws at once if they are energy efficient.

What Will A 4000-Watt Generator Run For A Work Site?

Below is an estimated power requirement of various tools on a site. Calculate the surge and running watts of each appliance, then compare it with your generator.

Mostly, 10000-watt generators are preferred for work sites, but a 4000 should do the job if there is no other option available.

Checkout our guide about best 5000 watt generators?

ApplianceRunning wattsSurge watts
Circular saw14002300
Electric drill600 watts600 watts
Portable air compressor ½ HP10001600
Chainsaw15001500
Bench grinder14002500

How To Safely Run A 4000-Watt Generator?

  • Before refueling, turn off the generator. Let it cool for a couple of minutes.
  • Don’t plug the generator in a wall outlet if you don’t know how to do it. Only licensed electricians should plug the generator into a main electrical panel or wall outlet.
  • Plug your equipment directly into the generator using a heavy-duty outdoor extension cord that handles high loads if your generator is not plugged into the main electrical panel.
  • Operate your generator in a dry place where plenty of ventilation is available.
  • Don’t sit near the generator. They release CO (carbon monoxide) which is an odorless poisonous gas. If proper ventilation is not available, CO can be accumulated in one place and can harm you in a bad way.
  • Change the oil and spark plug when it is due. Don’t be clumsy. Using the same oil for a longer period can cause internal friction and potential damage.

I am a passionate environment engineer, who has been in the solar, and inverter generator industry for years. I have been a part of multiple safety and environment-related courses such as IOSH, Fire Safety, Solid Waste Management, etc. I have been installing solar plants for residential purposes since 2018.

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