what can a 4000 watts generator run

What Can a 4000 Watts Generator Run?

The unforgiving hurricane season is here again. There’s one thing that’s assured – Blackout! 

So you preemptively try to get a generator?  But will a 4000-watt generator run the basic electronic appliances in your home?

Can it give out enough power to keep food in the refrigerator cold, TV, Lamp lights, and a couple of other small gadgets? 

The question is yes, but there’s more; 

To know whether you can run the basic essentials you will need in terms of a power outage like fridge, dishwasher, toaster, ceiling fan, Laptop, Smartphone etc.

  You need to understand the starting and running watts of all the electric appliances you are trying to run with the 4000 watt generator. 

Understanding Starting and Running Watts

The starting watt also known as surge watt is the required amount of power to start the motor of an appliance.  Starting watt is most important on larger appliances, smaller appliances don’t necessarily need it to run.

This bring us to running watt or continuous which is simply the power needed to run your machine over time.  A typical 4000 watt Generator (Running watt) provides about 33 amps from a 120 Volts and about 16.6 amps in 240 volts.

The most important factor when purchasing a 4000-watt generator is to ensure the power rating is the running watt. 

Surge watts are higher than the continuous watt which why it is important that the power rating of your generator is 4000 watt. Per experience, the starting watt is about 4200 to 4500 watt depending on the model.   

Best 4000 Watt Generators in 2020 – Our Top Picks 

The Generators mentioned in our list tick all the boxes of fuel-efficient, dual fuel, silent and durable. 

Frequently Asked Question (FAQs)

In the FAQ section. We will answer a lot of questions that people often ask me via the contact form. And surprisingly, similar questions keep getting asked. So I thought it better to make an FAQ section that outlines most of the already answered questions. 

Another important note you should remember is when using the generator is to make sure the appliances you are running do not exceed the power rating of the generator (Starting and running watt). As recommended by professionals, the generator should not perform above 90% of its power rating. 

What Will a 4000 Watt Generator Run In a Home? 

The table below contains appliances can you can run and the starting and running watt needed to safely run. 

Will a 4000 Watt Generator Run A Space Heater? 

This is an estimated wattage requirement of a space heater. Check-in with the manuals to get the actual wattage rating. 

1800 running watts and 0 starting watts. 

If you remember earlier I mentioned the starting or running watt not exceeding 90% of its power rating. It can run a space heater, and still, have enough power for other smaller appliances easily.  

Will A 4000 Watt Generator Run A Microwave? 

A typical example of the power needed to run a microwave is roughly 1000 running watts. It requires 0 surge watts to power the motor.

 In that case, you can safely run a microwave and clearly get a pass to charge a laptop and smartphone and even plug in a microwave and Tv. 

Will A 4000 Watt Generator Run A Sump Pump? 

Sump pumps are under the category of larger appliances that consume power. If it’s not important I advise you to avoid running the sump pump completely.  However, there are small sump pumps (1/3 horsepower) that require about 800 running watts and 1300 starting watts.

A ½ Horsepower needs 1050 running watts and 2100 starting watts.  The starting Watts as you can see requires considerable power.

You have to ensure the generator starting watts exceed the running watt watts. If you are yet to buy the generator, we have made a list of the best 4000 watts generators on the market. 

For larger appliances like the sump pump, ensure you have a 240 V outlet on the generator. 

Will A 4000 Watt Generator Run A Central Air Conditioning? 

A 4000 watts generator is not efficient to run a standard central air conditioning unit. This is a result of the starting watts which a standard AC will require more than 90% power rating of the generator to run.  If you still ignore the warning, you risk breaking your generator or burning the AC motor completely.

There are generators out there that require less than 4000 watts to run central AC but I recommend you contact the manufacturers to be on the safe side. 

Will A 4000 Watt Generator Require A Transfer Switch? 

Make no mistake of directly connecting your generator to the main electrical system of your house. Larger appliances utilize 200 – 240 volts which could damage appliances or fry your electric lines. 

Use a transfer switch to connect your generator for safe use. A transfer switch is of paramount importance, it’s a matter of life and death if you don’t use it. 

Will A 4000 Watt Generator Run A Refrigerator/Freezer? 

A typical refrigerator/freezer requires a minimum of 1200 surge watts to kick start the motor while it steps down to 200 running watts. This is on the condition your refrigerator does not fit in 10 sized adults inside (Pun intended).  Still, this is a rough estimate.

You can check your refrigerator or freezer’s power rating by reading the manuals or contacting the manufacturers.  Ensure your fridge is plugged into a stabilizer. 

This will help in mitigating the risk of damaging the high total harmonic distortion. A 4000-watt generator will be able to run two refrigerators easily. 

Will A 4000 Watt Run A TV? 

Absolutely! A 4000 watt generator will absolutely run any type of TV.  A Television, no matter how large would consume no more than 400 running watts and 500 starting watts. So there you have it, you can run more than 3 TVs on the generator with little trouble. 

Will a 4000 Watt Generator Run A Welder? 

Welding can consume ample power. A 4000 watt generator to run a welding setup might be insufficient. In this case, you should contact your brand’s manufacturer.  There’s an article where we discussed the best generators for welding activities.

The products mentioned in the article have been tested first hand by welders, a guarantee that you have the best generator for the job. 

Will A 4000 Watt Generator Run An Air Compressor?

 Well, it depends on the Air compressor’s horsepower. A ¼ would efficiently run on a 4000 running watts generator. But if compressors are different and you must check the manual to know the running and start watt of the appliance. 

But you can expect a rough estimate of wattage from the following horsepower;  ½ horsepower – Requires 980 running watts and 1600 starting watts  1 horsepower – requires 1600 running watts and 4500 starting watts. 

From the above, you can see that if the Air compressor is less than one horse then it can run the generator. 4500 starting watts is enough but would likely make your generator perform at more than 90% its capacity.  

Most Quiet 4000 Watt Generators? 

The table of the top 4000 watts generators is judged on quiet function, dual fuel options, running time, and efficiency. So if you looking for the quietest generators, you can’t go wrong with any from the list.

Will a 4000 Watt generator Run My Rv?

Yes, a 4000-watt generator is a good option and an affordable option for your RV. However, you have to deal with noise. If you are irked by the noise produced then you will need a quieter option in an Inverter. Check our top inverter generator reviews.

How long does a 4000 Watt Generator Last? 

The life of your generator depends on how you manage it. How well do you service it? Does it have an enclosure to protect it against harsh weather? These are questions you need to ask yourself. If you can manage your generator well enough, then you can use it for a decade.

What power tools will a 4000-watt generator run?

A 4000-watt generator can power the following power tools;

Work Appliance(s)Running (Continuous Watts)Additional Starting (Surge Watts)
Quartz Halogen Work Light300 300
Quartz Halocen Work l.iqht, 500 500
Quartz Halogen Work Light, 1000 1000
Airless Sprayer - 1/3 HP 600 1200
Reciorocatinq Saw 960 0
Electric Drill-3/8 ", 4 Amps 440 600
Electric Drill-1/2 ", 5.4 Amps 600 900
Hammer Drill 1000 3000
Circular Saw - 7 1/4 1400 2300
Miter Saw - 101800 1800
Planer/Jointer - 61800 1800
Table Saw/Radial Arm Saw 102000 2000
Belt Sander 1200 2400
Air Compressor - 1/4 HP 975 1600
Air Compressor 1 HP 1600 4500

How Many Amps Can A 4000 Watt Generator Handle?

A 4000-watt generator provides about 16 amps, in case of 120 volts or 8 amps in case of 240 volts

How To Determine Your Wattage Requirements 

Determining your wattage requirement is not rocket science. I know most people would love to skip this part but please don’t. It’s simple as adding your fingers together, well it’s not that easy but you get the point.  I will make this into a step by step list to ease you into the whole process of estimating how much watts you will need. 

  1. Make a list of all the appliances you want to run. You can check the list of wattage estimates below or check your manual. 
  2. Write down the starting and running watts into a table 
  3. Add the running watt required to run the electronics on one side and the starting watts on the other. 
  4. The total number of starting watts and running watts from each side will determine the size of the generator you should buy. 

I hope you find it helpful. If unclear, please you can use the contact page to reach out. I will be glad to help you the best I can.


Estimated Wattage

Kitchen Electronic applianceRunning (Contiguous Watts)Additional Starting (Surge Watts)
Coffee Maker10000
Electric Can Opener1700
Deep Freezer5001500
Food Processor4000
Electric Stove (8" Element)21000

EntertainmentRunning (Rated Watts)Additional Starting (Surge Watts)
Video Game System400
VCR/DVD player1000
Security System5000

Heating/Cooling Appliances Running (Rated Watts) Additional Starting (Surge Watts)
Light Bulb 60 Watt600
Space heater18000
Furnace Fan Blower 1/2 HP8002350
Furnace Fan Blower 1/3 HP7001400
Window AC 10,000 BTU1200 3600
Window AC 12,000 BTU 32509750
Central AC 10,000 BTU15004500
Central AC 24,000 BTU380011400
Central AC 40,000 BTU 600018000
Heat Pump45004700
Well Water Pump 1/2 HP 1000 2100
Garage Door Opener (1/2 HP) 875 2350

Laundry Appliance(s)Running (Continuous Watts)Additional Starting (Surge Watts)
Iron 12000
Curling Iron 1500 0
Washing Machine 1150 2250


Wattage Estimate

Tailgating/Camping ApliancesRunning (Surge Watts)Additional Starting (Surge watts)
Electric Grill 1650 0
AM/FM Radio 100 0
CD/DVD Player 100 0
Box Fan - 20" 200 0


Wattage Estimate

Office AppliancesRunning (Continuous Watts)Additional Starting (Surge Watts)
Personal Computer w/17" Monitor 800 0
Fax Machine 65 0
Laser Printer 950 0
Inkjet Printer 80 0
Copy Machine 1600 0


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