Matt Johnson

What Size Generator Do I Need for my RV?

Author: Matt JohnsonPhotos/Graphics: Mike HawthornePublished: Jul 21, 2022Updated: Dec 13, 2023

While most trailers, motorhomes, or RV owners install solar panels and battery systems to produce their electricity to run microwaves, refrigerators, and ACs, a decent-sized RV generator comes in handy during emergencies or when there are clouds and solar is not working correctly.

Even the most advanced and luxurious recreational vehicles need generators for emergencies and to run high-load appliances. However, if you have access to shore power, you should have more than enough power and shouldn’t necessarily need an inverter generator.

But before buying a generator, you might be wondering what size generator I need for RV? What size generator is big enough to run AC in my RV? How much power do I need to run my fridge? Can I power my entire with it? 

Let’s find out some answers.

Let’s start by discussing wattage.

Generator size for an RV depends on the size of your vehicle, the number of appliances you want to run, and starting and running watts of those appliances. 

A typical class C RV with 1 AC unit requires a 2500 to 3500-watt generator, a class A RV with two AC units requires a 6000 to 8000-watt generator, and a fifth wheel with two AC units requires a 5500 to 7000-watt generator.

Sure, it would be nice if there were a RV generator size calculator, but the truth is that every camper is different and with that the RV generators will be different as well.

Common generator sizes for different RVs.

These vehicle sizes can change based on your needs, but I have mentioned the most common types that most campers are using, including me. 

RV TypeAC UnitsGenerator Size in Watts
  Class B Van  One  2,500 to 3,500
  Class C RV  One  6,000 to 8,000
  Class A RV  Two  5,500 to 7,500
  Class A RV  Three  10,000 to 12,000
  Fifth Wheel  Two  5,500 to 7,500

How do you calculate wattage for RV Generator?

To calculate the wattage of your appliances, you need to multiply volts into amperes. 

Watt = Volts x Amps

Most information on watts, volts, and amps is mentioned on the sticker inside your fridge. For example, for an old fridge, 115V and 6.5 amps are standard.

Volts x Amps

115 x 6.5 = 747.5

What wattage to typical appliances use in an RV?

Many appliances energy consumption is rated in BTU.

BTU stands for British Thermal Unit, which is the unit of energy used to measure power and heat output from different sources.

A BTU is the amount of heat required to raise one pound of water one degree Fahrenheit at sea level. This unit is often used when looking at efficiency ratings for appliances such as air conditioners or furnaces, or when calculating energy consumption in a building or home.

ApplianceRunning wattsSurge watts
RV AC Unit (10,000 BTU)16001000
RV AC UNIT (15,000 BTU)33002000
RV FRIDGE600180 to 190
Incandescent lights6060
A standard fridge1200200
Microwave oven10001000
Coffee maker600600
AC (10,000) BTU44003000
Electric blanket200200
Incandescent lights300300
Electric Stove10001500 to 2000
Curling Iron001500

Before diving into the topic, learn the difference between starting and running watts.

What is the difference between starting and running watts?

Starting, peak or surge watts means a brief surge in power required to start a motor-driven device. Running or rated watts refer to continuous power necessary to run a device.

Motor-driven devices such as a refrigerator require a brief surge in power to overcome inertia and start. Shortly after it is started, the refrigerator settles down to its original power requirement (running watts).

What is the difference between 30 amp and 50 amp in an RV?

A 50-amp plug can handle a bit more power than a 30-amp service. A 50 amp plug has four prongs, two 120V hot wires, a neutral wire, and a ground wire that supply two separate 50amp, 120V feeds. A 50-amp service can handle as high as 12,000 watts. 

A 30-amp plug is used for lower load requirements. It has one 120V hot wire, a neutral wire, and a ground wire. It can handle as high as 3600 watts. Even with an adapter, a 30-amp service is limited to 3600 watts.

What size of generator do I need for a 30 amp and 50 amp RV?

A 30-amp connection with 120V equipment can handle up to 3600 watts. A 4000 – 4500-watt generator would be an ideal choice.

A 50-amp RV plug can handle up to 12000 watts with its two separate 50 amp feeds, but it doesn’t mean we have to lug around a huge 12000 to 15000-watt portable generator with us. That’s the size of a generator for fifth wheels that have multiple air conditioning units and plenty of appliances.

You’ll need plenty of power output to handle all of that.

A typical 6,000 to 7,500-watt portable inverter generator will do the job because we have to save space and reduce weight in our vehicle.

What size of generator is needed to power an RV’s AC unit?

ACRunning wattsStarting wattsGenerator
  7000 BTU  600  1700  2000 watt
  10,000 BTU  700  2000  2500 watt
  13,500 BTU  1250  2700  3000 watt
  15,000 BTU  1500  3500  4000 watt

So, what is the best generator for an RV?

Based on my expertise and experience, I would suggest getting a Portable RV Generator with inverter technology over a conventional generator based on the following reasons:

  • Inverter generators are significantly quieter.
  • They provide clean power with minimum harmonic distortion. You can charge and power your sensitive appliances like laptops, drones, cellphones, coffee makers, etc. 
  • They are built to be highly compact and portable, so campers and RV users can lug them around without any problem.
  • Inverter generators have excellent fuel efficiency.
  • 90% of the inverter generators have eco-mode to increase fuel efficiency and reduce noise when not in use.

The best part of inverter generators is that they are very quiet, which is one of the essential things for camping. Make sure you look at the portable RV generator options to get the best one for your needs.

Some of the quietest portable generators for RV are:

  • Honda EU2200i = 1800 running watts, 2200 starting watts.
  • Westinghouse iGen 4500 = 3700 running watts, 4500 starting watts.
  • Champion 4500W = 3500 running watts, 4500 starting watts. 
  • Generac GP3000i = 2300 running watts, 3000 starting watts. 

Many of these RV generators we listed are small enough that you should have no problem coming up with generator storage ideas. Keep in mind, you’ll have to have a place to store it while it’s running and while you’re on the road.


Matt Johnson

Senior Content Writer

Matt is an experienced camper and glamping enthusiast with a Master's degree in Wildlife Science from Texas A&M University. Authoring posts for GlamperGear, he shares his wealth of knowledge on picturesque campsites, luxurious accommodations, and the best gear for outdoor adventures. His passion for nature and knack for comfort in the wilderness make him an expert guide for your next camping endeavor.

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