What Can a 4000-Watt Generator Run?-Unleashing Its Potential

This article aims to answer your burning question about “What Can a 4000-watt Generator Run?” how many appliances can we run simultaneously and how can we determine our actual needs?

A 4,000-watt generator could run almost every essential of a household, RV, or worksite including space heaters, microwaves, RV Air conditioners, Window Air conditioners, Refrigerators, washing machines, Home theater, Different saws, grinders, etc.

What Can a 4000-Watt Generator Run?

What Can a 4000-Watt Generator Run?

Our DuroMax XP4000S (4kw machine) performed well with the following appliances.

  • Small LED TV (under 50 inches)
  • Laptops
  • Jumbo-sized Refrigerator/Freezer
  • Water Pump
  • Space heater
  • Clothes Iron
  • Desktop Computer
  • Printer
  • Toaster
  • Washing Machine
  • Coffee Maker
  • Vacuum
  • Air conditioner of 1,0000 – 1,4000 Btu
  • Well pump
  • Printer
  • Dishwasher
  • Microwave
  • Circular Saw

Starting and Running Watts

Starting/Peak watts: The number of watts that can a generator produce for a small time to provide the initial startup to the motorized appliance/equipment. Starting wattage will always be higher than running/rated wattages.

Running/Rated watts: The number of wattages that a generator can produce for a long with stability. Running wattage will always be lesser than the starting wattage.

NOTE: You can find both wattage ratings from the specification of the machine.

List of Appliances a 4000 Watt Generator Can Run

ApplianceRunning WattsStarting Watts
Coffee Maker10000
Cell Phone Battery Charger250
Ceiling Fan6070
Deep Freezer5001500
Clock Radio50-2000
Copy Machine16000
Electric Can Opener1700
Electric Mower15000
Common Light Bulb750
Electric Kettle12003000
Electric Strimmer300500
Electric Stove (8″ Element)21000
Furnace Fan Blower (1/2 HP)8002350
Food Dehydrator8000
Garage Door Opener (1/2 HP)8752350
Furnace Fan Blower (1/3 HP)7001400
Outdoor Light String2500
Paper Shredder200220
Humidifier (13 Gal.)1750
Pressure Cooker7000
Space Heater18000
Refrigerator / Freezer7002200
Sump Pump (1/2 HP)10502150
Rice Cooker200500
Security System5000
Sump Pump (1/3 HP)8001300
Well Water Pump (1/2 HP)10002100
Home Internet Router515
Window AC (10,000 BTU)12003600
Home Phone35
Clothes Dryer (Gas)7001800
Curling Iron15000

Recommended Guide: What can a 3,000 watt generator run?

How Many Things Can a 4000-Watt Generator Run at the Same Time?

It depends, if you have an appliance of 3,500 running and 3,800 starting watts you can only run that device at once.

On the other hand, if you have to run multiple appliances, make sure that the sum of their wattages shouldn’t be more than 3,800 running and 4,000 starting wattages.

Below is the guide to calculating your wattage needs.

How to Determine Your Needs?

  • Make a list of your required appliance and write down their starting and running wattages in separate Columns, starting and running wattages could be found in the energy labeling of the product.  If you found the ratings in Amps then you should use the below formula to convert them first.

Watts (W or kW) = Volts (V) x Amps (A)
Amps (A) = Watts (W or kW) / Volts (V)

E.g. An appliance is consuming 9A of running and 10A of starting Amps at the voltage of 220 Volts.

As per the above formula “Watts = Volts X Amps”

Starting Watts: 10×220 = 2,200 watts

Running watts: 9×200 = 1,980

  • Sum up the starting and running wattages, and keep them in a separate Colum.  Compare the total starting and running wattages with the machine you are going to purchase.

Practical Example:

AppliancesStarting WattsRunning Watts
Refrigerator1200 Watts200 Watts
Dishwasher1500 Watts1500 Watts
Washing Machine0 Watts1200 Watts
Microwave0 Watts800 Watts
Laptop0 Watts60 Watts
TOTAL2700 Watts3760 Watts

From the above table, we got 3760 running and 2700 starting watts. A 4,000-watt machine could easily handle that load.

NOTE: Don’t ever operate a machine at 100% capacity (full capacity), make sure to keep a margin of 10% – 20%, this will not only saves the fuel cost and keep the voltage in stable condition but also makes sure to that the repairing cost should be minimum down the road.

Recommended Guide: What Can a 3500 Watt Generator Run?

Will a 4000 Watt Generator Run a Refrigerator?

Yes, a jumbo-sized refrigerator with a freezer is consuming about 1,200 running and 2,000 – 2,200 starting watts; however, a 4kw generator has the capacity to produce even double power than that.

Can a 4000 Watt Generator Run a Furnace?

It depends, a normal household has a furnace of 400 – 800 wattages; however some large furnaces have 7,000 – 10,000 watts which isn’t practically possible to run with a 4kw unit.

Will a 4000 Watt Generator Run an AC?

It depends; a small RV or window Ac couldn’t be a big deal for a 4kw machine, however, if you are going to run a central air conditioner you may have to consider a bigger one.

Below is the list of window ACs with sizes and wattage ratings.

  • 11,000 window AC units consume almost 1100 to 1200 running watts and 1600 – 1700 starting watts.
  • 12000 window AC units consume 1200 to 1350 running watts and 2000 to 2200 starting watts.
  • 15000 window AC units consume 1600 – 1800 running watts and 2500 to 2700 starting watts.

How Long Will a 4000-Watt Generator Run on a Gallon of Gas?

On average a generator provides 3– 3.5 hours depending on the load, if you are stretching your generator to its full capacity (100% load) you may get very less runtime, however with 25% – 50% load your generator will provide optimum efficiency with desired runtime.

Recommended Guide: What Can a 5000-Watt Generator Run?

Final Words

Though 4kw is an ideal size for a small to medium household, Rv, or Job site, still an extensive calculation should be done before making a buying decision.

The calculation will not only save your one-time cost but also save the ongoing cost of fuel, maintenance, etc.

FAQs – Frequently Asked Questions

Will a 4000 Watt Generator Run a Welder?

No, an average welder consumes about 4500 watts.

Will a 4000 Watt Generator Run a House?

Yes, a 4kw generator runs almost everything in the house including microwave, refrigerator, air conditioner, space heater, lighting, fans, home theater, etc., however, if you are looking for a machine that can also power your extremely power-hungry appliances like tankless water heaters, heavy heating system, and air conditioners, etc. you should consider a bigger unit of 8kw – 10kw.

How Long Will a 4000-Watt Generator Run on Propane?

As per our tests, a 4,000-watt dual fuel generator provides 9 – 10 hours of runtime with propane at 25% load, however, if you increase the load the runtime will surely decrease.

Will a 4000 Watt Generator Run an Air Compressor?

Yes, a normal air compressor of 1hp consumes about 1,200 – 1,500 running and 2,500 – 3,000 starting watts.

Will a 4000 Watt Generator Run a Circular Saw?

Yes, a circular saw consumes about 1500 – 2000 watts which isn’t a big deal for a 4,000-watt machine.

Will a 4000 Watt Generator Run a Space Heater?

Yes, a normal household space heater consumes about 1500 – 2000

Will a 4000 Watt Generator Run a Microwave?

Yes, a normal microwave needs about 1,000 – 1,500 watts, a 4k could run 2 of them at the same time.

How Many Amps Does a 4000-Watt Generator Provide?

As per the calculations at 220V a 4kw unit generates about 18.18 amps, however, at 120V you will get 33.33 amps.

Note: we have used Ohm’s law.

Watts (W or kW) = Volts (V) x Amps (A)
Amps (A) = Watts (W or kW) / Volts (V)



Kashif has been a valuable asset to the electric generator industry for over 5 years. Now, As a skilled energy engineer, he’s been on the front lines of diagnosing problems, fixing broken parts, and performing routine maintenance tasks to keep generators running smoothly.

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