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FAQ: What Will a 4000 Watt Generator Run in a House?

Do you consider getting a 4,000 watt generator but you are not sure what appliances you can run on it? Then you have landed on the right website as our Generatorist team will try to give you every piece of information you are looking for.

There are two main wattage output numbers characterizing the amount of power each portable generator can produce at one time.

The first, smaller number, refers to rated (running) watts – the amount of power your machine can produce over longer periods of time. The second, larger number, refers to the surge (or starting) watts – the maximum power your machine can produce over a short period of time.

By a 4,000 watt generator we refer to a machine that is able to produce 4,000 running watts. Its starting watts will vary depending on the brand and model of each generator, but based on our experience the range is somewhere between 4,300 – 5,250 surge watts.

In layman’s terms, a 4,000 watt generator can run almost any essential household appliance, including:

  1. Small window AC unit
  2. Fridge with a freezer
  3. Microwave oven
  4. TV
  5. Sump pump
  6. Small heating system
  7. Computer
  8. VCR / DVD Player
  9. All smaller electric appliances
  10. A couple of power tools

To learn, whether you can run all these at the same time you need to know the power consumption of each appliance in your home. Also, you need to know whether your generator has the correct number and type of outlets as some higher wattage appliances such as AC units may need different outlets than some low-wattage appliances.

Just don’t expect to run your whole house on this machine simultaneously as this will require a lot more power than any 4,000 generator can provide. If you need an energy backup for your whole house without any limitations, you may consider getting a stand-by unit instead of a portable one.

Usually, these are much more expensive and need to be installed by a professional electrician.

Determining your

wattage requirements

If you want to learn what electronic appliances will a 4,000 generator run, you need to get ready to do some math. Don’t worry, it will be a very simple process of adding up several numbers.

To determine what appliances you can run on this type of generator at the same time, you need to follow these steps:

  1. List all electronic appliances in your home you want to keep running in the case you are out of power (here is a great list full of appliances you might use)
  2. Write information from their name tags on required running and starting watts into a table (see examples below)
  3. Then you need to add up all the running watts required to operate your appliances
  4. The next step is to find the item with the highest additional starting watts
  5. Then add this number to your total running watts
  6. The final number represent the amount of starting watts your generator needs to provide

Here is a good example of calculating wattage needs for a generator.

We have decided that in case of a weather-caused blackout, we would need only essentials such as refrigerator with a freezer so our food will be safe, a lamp that will serve as an emergency light source, a small window AC unit to keep the temperature under control, a toaster, and a laptop.

Selected Appliances Rated (Running) Watts Additional Starting Watts
Toaster 850 W 0 W
Refrigerator / Freezer 700 W 2,200 W
Laptop 300 W 0 W
Lamp (2 Lightbulbs) 150 W 0 W
Window AC (10,000 BTU) 1,200 W 3,600 W
TOTAL 3,200 W
6,800 W

As you can see in our example above, if we add up all running watts of our appliances we get the number 3,200 – so we are well within the 4,000 running watts limit (850 + 700 + 300 + 150 + 1,200 = 3,200).

However, we would need a generator that is capable of producing at least 6,800 surge (starting) watts to power all these appliances (3,200 + 3,600 = 6,800).

Just keep in mind that some electric appliances in your home may not have running watts provided on their data tags. If this is the case, you can estimate the running watts required thanks to the following formula:

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

So, as long as you have required Volts and Amps, you can easily convert them into an estimate of required running watts. Maybe you remember that this equation represents the Ohm’s law from High School physics.

Luckily, there is a device called “appliance load tester” that you can get to determine how many watts each your appliance takes. You can easily get one from Amazon and avoid all that physic´s equation.

If you need general estimates of wattage consumption for the most common electronic appliances, then take a look at our tables below. Just take these numbers as rough estimates. You need to check each appliance / power tool in your home individually to see the precise wattage requirements.

How much can a 4000 watt generator run? Check out the wattage of the most popular appliances below to discover answer to that question.

Essential Appliances

Estimated wattage
Household Appliances Rated (Running) Watts Additional Surge Watts
Heat Pump 4,700 W 4,500 W
Humidifier (13 Gal.) 175 W 0 W
Electric Water Heater 4,000 W 0 W
Well Water Pump (1/2 HP) 1,000 W 2,100 W
Window AC (10,000 BTU) 1,200 W 3,600 W
Window AC (12,000 BTU) 3,250 W 9,750 W
Central AC (10,000 BTU) 1,500 W 4,500 W
Central AC (24,000 BTU) 3,800 W 11,400 W
Sump Pump (1/3 HP) 800 W 1,300 W
Sump Pump (1/2 HP) 1,050 W 2,150 W
Furnace Fan Blower (1/3 HP) 700 W 1,400 W
Furnace Fan Blower (1/2 HP) 800 W 2,350 W
Garage Door Opener (1/2 HP) 875 W 2,350 W
Common Light Bulb 75 W 0 W
Space Heater 1,800 W 0 W
Ceiling Fan 60 W 70 W

Kitchen Appliances

Estimated wattage
Household Appliances Rated (Running) Watts Additional Surge Watts
Toaster 850 W 0 W
Microwave 1,000 W 0 W
Refrigerator / Freezer 700 W 2,200 W
Coffee Maker 1,000 W 0 W
Electric Stove (8" Element) 2,100 W 0 W
Deep Freezer 500 W 1,500 W
Electric Can Opener 170 W 0 W
Dishwasher 1,500 W 1,500 W
Food Processor 400 W 0 W
Electric Kettle 1,200 W 3,000 W
Food Dehydrator 800 W 0 W
Fryer 1,000 W 0 W
Pressure Cooker 700 W 0 W
Rice Cooker 200 W 500 W

Laundry Appliances

Estimated wattage
Household Appliances Rated (Running) Watts Additional Surge Watts
Clothes Dryer (Gas) 700 W 1,800 W
Clothes Dryer (Electric) 5,400 W 6,750 W
Hair Dryer 1,250 W 0 W
Iron 1,200 W 0 W
Washing Machine 1,150 W 2,250 W
Curling Iron 1,500 W 0 W
Electric Shaver 15 W 20 W
Vacuum Cleaner 200 W 700 W

Entertainment Appliances

Estimated wattage
Household Appliances Rated (Running) Watts Additional Surge Watts
Laptop 300 W 0 W
Stereo 450 W 0 W
Television 500 W 0 W
VCR / DVD Player 100 W 0 W
Video Game System 40 W 0 W
Monitor 200 - 250 W 0 W
Home Internet Router 5 W 15 W
Home Phone 3 W 5 W

Other Appliances

Estimated wattage
Household Appliances Rated (Running) Watts Additional Surge Watts
Clock Radio 50 - 200 W 0 W
Fax 60 - 80 W 0 W
Printer 400 - 600 W 0 W
Security System 500 W 0 W
Garage Door Opener (1/2 HP) 875 W 2,350 W
Copy Machine 1,600 W 0 W
Cell Phone Battery Charger 25 W 0 W
Outdoor Light String 250 W 0 W
Electric Mower 1,500 W 0 W
Paper Shredder 200 W 220 W
Projector 220 W 270 W
Scanner 10 W 18 W
Electric Strimmer 300 W 500 W
Treadmill 280 W 900 W

Printable Chart

power tools & machines

Estimated wattage
Power tools Rated (Running) Watts Additional Surge Watts
Concrete Vibrator (2 HP) 1,800 W 3,600 W
Concrete Vibrator (1 HP) 1,100 W 2,500 W
Concrete Vibrator (0.75 HP) 850 W 1,900 W
Radial Arm Saw 2,000 W 2,000 W
Circular Saw (7.25") 1,400 W 4,200 W
Air Compressor (0.25 HP) 975 W 1,600 W
Air Compressor (0.5 HP) 1,000 W 2,000 W
Air Compressor (1.5 HP) 2,200 W 6,000 W
Air Compressor (2 HP) 2,800 W 7,700 W
Air Compressor (1 HP) 1,600 W 4,500 W
Miter Saw (10") 1,800 W 1,800 W
Reciprocating Saw 960 W 0 W
Electric Drill 600 W 900 W
Belt Sander 1,200 W 2,400 W
Bench Grinder 1,400 W 2,500 W
Chain Saw 12” (1.5 HP) 900 W 0 W
Jig Saw 300 W 300 W
Pressure Washer (1 HP) 1,200 W 3,600 W
Rebar Cutter (1") 2,800 W 0 W
Disk Sander 1,200 W 2,600 W
Orbital Sander 1,200 W 2,600 W
Impact Wrench (1") 1,200 W 1,400 W

Essential Equipment

Estimated wattage
Power tools Rated (Running) Watts Additional Surge Watts
Floodlight 1,000 W 0 W
Heater (Liquid Fuel 50,000 BTU) 225 W 675 W
Heater (Liquid Fuel 100,000 BTU) 420 W 1,260 W
Heater (Liquid Fuel 150,000 BTU) 625 W 1,875 W
Sump Pump (1 HP / 230 V) 715 W 7,200 W
Sump Pump (1 HP / 115 V) 1,440 W 7,500 W

Farm Equipment

Estimated wattage
Power tools Rated (Running) Watts Additional Surge Watts
Electric Fence (25 Miles) 250 W 250 W
Milk Cooler 1,100 W 1,800 W
Milker / Vacuum Pump (2 HP) 1,000 W 2,300 W

Gardening Power Tools

Estimated wattage
Power Tools Rated (Running) Watts Additional Surge Watts
Electric Strimmer 300 W 500 W
Electric Mower 1,500 W 0 W
Hedge Trimmer 600 W 450 W
Weed Cutter 600 W 500 W
Chain Saw 12” (1.5 HP) 900 W 0 W
Cultivator (1/3 HP) 700 W 1,400 W

Printable Chart

Essential Appliances

Estimated wattage
Camping / RV Appliance Rated (Running) Watts Additional Surge Watts
Space Heater 1,800 W 1,800 W
4 Light Bulbs (75W) 300 W 300 W
Heating Pad 250 W 250 W
RV Roof-Top AC (13,500 BTU) 1,500 W 2,000 W
Furnace Fan (1/3 HP) 700 W 1,400 W
Electric Blanket 80 W 1,250 W
Fan 200 W 200 W
Electric Water Heater (6 Gal.) 1,440 W 1,440 W
Dehumidifier 785 W 1250 W

Washing Appliances

Estimated wattage
Camping / RV Appliance Rated (Running) Watts Additional Surge Watts
Vacuum 1,100 W 1,100 W
Curling Iron 800 W 800 W
Shaver 35 W 35 W
Blow Drier (Hair) 1,250 W 1,250 W
Iron 1,200 W 1,200 W
Clothes Washer 1,150 W 2,300 W

Kitchen Appliances

Estimated wattage
Camping / RV Appliance Rated (Running) Watts Additional Surge Watts
Electric Can Opener 170 W 0 W
Hot Plate 1,200 W 1,725 W
Waffle Iron 1,200 W 1,725 W
Electric Grill 1,650 W 1,650 W
Deep Fryer 1,200 W 1,200 W
Chest Freezer 450 W 900 W
Slow Cooker 170 W 270 W
Toaster 850 - 1,250 W 850 - 1,250 W
Toaster Oven 1,200 W 1,200 W
Dorm Size Refrigerator 350 W 500 W
Microwave (635W Cooking Power) 635 W 800 W
Electric Fry Pan 1,200 W 1,200 W
Coffee Maker 800 W 800 W
Corn Popper 275 W 275 W
Crockpot 250 W 250 W
Blender 350 W 500 W

Entertainment Appliances

Estimated wattage
Camping / RV Appliance Rated (Running) Watts Additional Surge Watts
Inflator Pump 50 W 50 W
AM/FM Cassette 10 W 10 W
Stereo 450 W 450 W
VCR 100 W 100 W
Satellite Dish & Receiver 30 W 250 W
Radio 2-Way 360 W 960 W
27" Color TV 500 W 500 W
19" Color TV 160 W 160 W
12" B&W TV 30 W 30 W
Desktop Computer 600 W 800 W
Laptop 200 W 250 W
Printer 500 W 500 W
CD/DVD Player 50 W 200 W
Clock Radio 100 W 100 W

Printable Chart

Looking for a 4000 watt generator?

4,000 Generator FAQ

Frequently asked questions

Because we got a lot of questions over time with regards to 4,000-watt generators, we have decided to add this FAQ section where you can look for helpful information.

If you have questions that are not answered here, feel free to contact us or leave your question in the comments section available at the end of this article.

In general, this type of machine can run almost any essential household appliance, including:

  1. A small window AC unit
  2. Fridge with a freezer
  3. Sump pump
  4. Medium radiant heater
  5. All smaller electric appliances
  6. A couple of power tools

Whether you can run all these at the same time you need to know the power consumption of each appliance in your home. Also, you need to know whether your generator has the correct number and type of outlets as some higher wattage appliances such as AC units may need different outlets than other low-wattage appliances.

Just don’t expect to run your whole house on this machine simultaneously as any 4,000-watt generator will have too little power to do so. We have provided tables with rough estimates for individual electric appliances in this article.

If you need to provide an energy backup for your whole house without any limitations, you may consider getting a standby unit instead of a portable one.

Usually, these are much more expensive and need to be installed by a professional electrician.

In general, a 4,000 running watts generator doesn’t provide enough power to run a heat pump or electric furnace. However, answering this question is really hard without knowing the exact running and starting watts required by your electric appliance.

Please, contact a manufacturer of your pump or furnace to learn more info on its wattage requirements. Also, we have discovered a forum thread where this question is answered in more details so don’t forget to check it out.

Sadly, there is not a single answer to this question. To learn, whether you can run your welder on a 4,000-watt portable generator you need to know the power requirements of your welder (see the data tag or user manual you got to your welder).

However, based on the information we were able to learn, the best option is to get a special generator that has been manufactured for welding purposes such as LIFAN AXQ-200A to be able to harness the full potential of your welder.

You can see some good options on Home Depot.

In general, a 4,000 – 4,300 running watts generator should provide enough power to run a small air compressor without any issues. However, answering this question is really hard without knowing the exact running and starting watts required by your air compressor.

I have found rough estimates for different types of compressors:

  • 1/2 Horse Power – It takes 975 running watts and 1,600 starting watts.
  • 1 Horse Power – It takes 1,600 running watts and 4,500 starting watts.

As you can see in the estimates above, the issue is not running watts but starting watts. To get the precise numbers, you will need to find the voltage, amperage, and horsepower information on the info-plate of your compressor.

Then, all it takes to learn required wattage is to apply this equation:

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

In general, a 4,000 – 4,300 running watts generator should provide enough power to run a small RV AC unit (11000 BTU) without any issues. However, answering this question is really hard without knowing the exact running and starting watts required by your AC unit.

I have found rough estimates for different types of RV air conditioning units:

  • 11000 BTU – It takes 1,050 running watts and 1,600 starting watts.
  • 13000 BTU – It takes 1,800 running watts and 2,800 starting watts.
  • 15000 BTU – It takes 2,000 running watts and 3,300 starting watts.

As you can see in the estimates above, the issue is not running watts but starting watts. To get the precise numbers, you will need to find the voltage and amperage information on the info-plate of your RV AC unit.

Then, all it takes to learn required wattage is to apply this equation:

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

In general, a 4,000 generator should provide enough power to run a circular saw. A rough estimate of power requirements of a heavy-duty 7.25″ circular saw is as follows:

  • 1,400 running watts
  • 2,300 starting watts

So, as long as your generator offers at least 2,500 starting watts (we recommend getting slightly more power than needed), you should be able to run your machine on this type of generator.

A rough estimate of energy requirements of a space heater is as follows:

  • 1,800 running watts
  • 1,800 starting watts

As you can see, you can easily run your space heater with a 4,000 – 4,300 running watts generator. Just don’t forget to double-check the name tag on your appliance to learn the precise wattage requirements.

In general, a common microwave needs around 1000 watts to operate. A 4000-watt generator has at least 4,000 running and 4300 starting watts so you can run your microwave pretty easily.

Just don’t forget to check the nameplate on your appliance to learn the precise wattage requirements.

In general, a refrigerator takes around 1200 surge watts at the beginning while the compressor kicks in and then it gradually drops down to around 200 running watts. As you can see, each and every generator in this article could run a mid-sized refrigerator.

However, you shouldn’t rely on these general estimates and you have to check the nameplate and data tag on your fridge to learn the precise numbers.

Also, if your generator has a high total harmonic distortion, your fridge (especially if you have a modern type) may get damaged (that is why we recommend getting an inverter type of generator).

Definitely. As long as your generator is an inverter with a low total harmonic distortion, then you can run your TV safely on a 4,000-watt generator.

Here are some rough estimates of wattage requirements of various TVs:

  • Tube type – It takes 300 running watts and 300 starting watts.
  • Flat Screen (20”) – It takes 120 running watts and 120 starting watts.
  • Flat Screen (46″) –  It takes 190 running watts and 190 starting watts.

As you can see, you will have enough spare power to run your DVD player that takes approximately 350 running and 350 starting watts as well.

Usually, a 4,000 – 4,300 running watts generator should provide enough power to run a small sump pump without any issues. However, answering this question is really hard without knowing the exact running and starting watts required by your pump.

I have found rough estimates for different types of sump pumps:

  • 1/3 Horse Power – It takes 800 running watts and 1,300 starting watts.
  • 1/2 Horse Power – It takes 1,050 running watts and 2,150 starting watts.

As you can see in the estimates above, the issue is not running watts but starting watts. To get the precise numbers, you will need to find the voltage, amperage, and horsepower information on the info-plate of your pump.

Then, all it takes to learn required wattage is to apply this equation:

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

Just keep in mind that your sump pump will probably require a 240V outlet on your generator.

In general, a 4,000 – 4,300 running watts generator should provide enough power to run a small well pump without any issues. However, answering this question is really hard without knowing the exact running and starting watts required by your water pump.

I have found rough estimates for different types of pumps:

  • 1/3 Horse Power – It takes 750 running watts and 1,500 starting watts.
  • 1/2 Horse Power – It takes 1,000 running watts and 2,100 starting watts.
  • 3/4 Horse Power – It takes 1,500 running watts and 3,000 starting watts.
  • 1 Horse Power – It takes 2,000 running watts and 4,000 starting watts.
  • 1 & 1/2 Horse Power – It takes 2,500 running watts and 5,000 starting watts.

As you can see in the estimates above, the issue is not running watts but starting watts. To get the precise numbers, you will need to find the voltage, amperage, and horsepower information on the info-plate of your pump.

Then, all it takes to learn required wattage is to apply this equation:

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

We have serious doubts that a 4000-watt generator would provide enough power to run a central AC unit. We would rather go for a very small emergency window AC unit as 4,000-watt generators may have too little starting power.

However, the answer to this question really depends on the number of running and starting watts your AC unit requires.

Obviously, these numbers vary from one unit to another and are based on the cooling ability of individual models and brands. That is why you need to look for the following data at the name tag of your central AC unit:

  1. LRA (Locked Rotor Amps) – This number represents the current you can expect under starting conditions when you apply full voltage.
  2. RLA (Rated Load Amps) – This number represents the maximum current a compressor should draw under any operating conditions.
  3. FLA (Full Load Amps) – This number represents the same as the Rated Load Amps.

You need to take into consideration the amps for both the compressor and the fan unit. To determine, if your 4,000-watt generator can run a central AC, please consult its manufacturer or a professional electrician.

Keep in mind that a typical central air unit runs on 208/240 volts and is often permanently mounted and hardwired into the electrical system of your house. That is why to safely run this electronic appliance you need to connect your generator through a transfer switch.

Actually, you should always connect your generator through a transfer switch if you don’t want to damage your appliances or endanger people who may be working on electric lines in your neighborhood.

In general, a 4000 watt gasoline generator has a 4-stroke engine. If this is the case, you will need to use either SAE 30 (if you live in a warmer climate) or a SAE 10W-30 if you are going to use it in a colder climate (do not forget to double-check with your owner´s manual).

However, there are several things you need to consider while choosing the oil for your machine:

  • Whether you got a 2-stroke or a 4-stroke engine
  • Starting and operating temperatures
  • Type of fuel your machine runs on
  • Certifications and classifications of the oil
  • Reputation of the brand and company producing the oil

If you need to learn more information on how to choose the best oil for your generator, then consult our guide that is available right here. We provide you also with a list of best brands in various categories of oil.

In general, a 4,000-watt generator provides approximately 33.3 amps, in case of 120 volts or 16.6 amps in case of 240 volts. To learn more, you should check out the owner´s manual to the machine you want to buy.

Actually, identifying how many amps there are in a 4000 running watt generator is a very simple process. All you have to do is to apply the following formula:

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

You need to divide the wattage by the voltage. So, in this case, you need to divide 4000 by 120 or 240 to get the correct numbers.

Although this question doesn’t have an universal answer as each generator has unique fuel consumption and capacity of the fuel tank, based on our database, an average 4,000 – 4,300 generator runs for approximately 10.2 hours on a 50% load.

This number is a median that we got after looking at the run time of over 13 generators that provide 4,000 – 4,300 running watts.

There is not a single correct answer to this question. Actually, there are several features of your 4,000-watt generator you need to consider while choosing your transfer switch.

We will be doing a guide on choosing the best transfer switches soon but in the meantime, consider this guide from Electric Generators Direct.

If you are looking for an RV generator, our advice is to choose a machine that is powerful but still quiet. Ideally, go for an inverter.

There are only two inverters in this category of generators that are also quiet at the same time:

  1. Yamaha EF4500iSE
  2. Wanco WI4300

There is also one RV ready generator in this category – the Pulsar PG5250B. If you want to get any other unit from this list, then you need to get a necessary set of adapters (also called dogbones) to easily connect your RV through either a 20 or a 30 amp outlets.

So pick a generator that fits your needs the most and if it is not RV ready, don’t forget to get the correct adapter.

Finding reliable information on the “noisiness” of generators is a tough job to do. However, based on our findings, we can list the following machines as “quietest”:

  1. Yamaha EF4500iSE
  2. Wanco WI4300

In general, if you want a portable generator that is powerful but also quiet at the same time, then go for an inverter. Sadly, these machines are much more expensive than regular generators.

If you are looking for a 4,000 -4,300 running watts generator that offers the most comfortable electric start, then we have only two options that stand out:

  1. Yamaha EF4500iSE (4,000 running / 4,500 starting watts)
  2. Wanco WI4300 (4,000 running / 4,300 starting watts)

Both machines are inverters and provide clean power. So choose one according to the maximum starting and running watts you actually require.

There are two 4,000 generators that are able to run on propane as well:

Both of these machines provide a good quality-vs-price ratio.

If you are looking for the best inverter generator that provides 4,000 – 4,300 running watts, then there are two options for you to choose from.

Based on our research, the best inverters in this category are:

  1. Yamaha EF4500iSE (4,000 running / 4,500 starting watts)
  2. Wanco WI4300 (4,000 running / 4,300 starting watts)

Just keep in mind that although inverters are running quietly, they are on the more expensive side.

recommended readings

About the author

Hands behind everything you see around. Matthew is the main workforce that puts all ideas into realization. So, do not feed him bad ideas.

Matthew

handyman, loves science

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