What Size Generator Do I Need to Run an RV Air Conditioner?

What Size Generator to Run RV Air Conditioner

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RVers know the importance of an RV air conditioner during summer.

It is one of the most essential RV appliances to keep you and your family comfortable.

You don’t have to worry about powering your AC unit if you’re camping with hookups.

But, what do you do when you’re boondocking or dry camping?

You’ll have to rely on a portable generator for RV.

But you can’t just use any size generator to power your RV air conditioner.

So you ask.

What size generator do I need to run an RV air conditioner?

It’s simple; you need a powerful enough generator to run your RV AC. A 3000-watt portable generator has enough power to run a 13500 BTU air conditioner.

However, it’s rare for RVers to use the air conditioner alone.

In most cases, you’ll have a few other appliances running simultaneously alongside your RV rooftop AC unit.

In this post, you’ll learn everything you need to know to find the right generator size for an RV AC unit. 

In the end, you’ll find my recommendations of the best generator for RV air conditioners to power both rooftop and portable RV AC.

Read More: How to properly size an RV generator for boondocking?

What Size Generator to Run RV AC?

The answer to the question “what size generator to run RV AC?” is anything but straightforward.

A 30 amp RV is small, comes with a single air conditioner and fewer appliances. On the other hand, a 50 amp RV is big, comes with 2 AC units and many appliances.

You need a generator that is powerful enough to run your AC and the appliances you plan on running together without overloading the generator.

A generator with 3800 starting and 3400 running watts can run a 13500 BTU RV air conditioner and a few other appliances together without any issue.

However, this may not be the right size generator for every RVer. It may be overpowered or underpowered for some.

To calculate the right size generator for your RV, you need to find out your total power needs. Let’s start by looking at the power guzzler, your RV air conditioner.

How Many Watts does an RV Air Conditioner Use?

Before finding out what size generator to power your RV AC, you need to know how much power they consume.

An RV air conditioner needs a starting and running wattage to run. 

A starting watt is an initial boost in power required to get the unit started. Whereas, the running watts are the continuous power needed to keep the appliance functioning properly.

Generally, starting wattage is higher compared to running wattage. The starting and running wattage of an air conditioner varies depending on factors like brand, size, and type of RV air conditioner.

Therefore, check your specific model documentation to find out your exact numbers. However, the table below will give you an idea of the starting and running watt of the most common sizes of RV AC units.

BTU RatingStarting WattageRunning Wattage

Note: The wattage ratings of all the appliances mentioned on this page are taken from Honda.

The generator you choose should be able to handle both the starting and running watts of your air conditioner.

Calculating Power Needed to Run other Appliances

By now, you know how big of a generator you need to run your RV air conditioner.

But, you’ll rarely run your ac alone. You most likely will have other appliances running along with your air conditioner. 

As such, you need to calculate the total power required by those appliances to find out what is the best size generator for you. 

Calculating the wattage ratings of the large appliances will make sure you don’t have to turn off one appliance to run the other.

However, make sure you only consider those high draw appliances that you use daily. Appliances such as microwaves, coffee makers, refrigerators, etc. draw the most amount of electricity.

The table below provides rough estimates of the starting and running wattage of a few household appliances. The numbers will vary depending on the brand and size of your appliances.

AppliancesStarting WattageRunning Wattage
Microwave Oven10001000
5200 BTU Space Heater750750
Coffee Maker600600
RV Refrigerator600180

Calculating your Total Power Needs

By now, you should have a list of the starting and running wattages of the appliances you plan on running together.

It’s now time to add them up to figure out your total power needs.

Let’s say, you wake up in the morning and fire up your generator.

The weather is warm and humid, so you turn on your 13500 BTU air conditioner. In the meantime, your wife is heating something in the microwave and brewing your morning coffee in the coffee maker.

Not to mention, your RV refrigerator is sipping juice silently.

At this point, you’re using about 3580 running watts of power approximately. 

Let’s say you fired up all the appliances at once (which is very unlikely).

You’ll need a portable generator that can produce 5000 surge watts.

Wait, there is more.

You can reduce the load on the generator if you are mindful of the appliances you use together.

Let’s take the above scenario and tweak it a bit.

Let’s say, you first heat the food in the microwave and then brew your coffee. Once done, you turn on the ac.

This way you’re using your generator to power your AC and refrigerator, that’s totaling about 3400 starting and 1980 running watts.

Depending on our above scenario, you’ll be good with a generator that comes with 3500 surge watts + 20% extra; i.e. 4200 starting watts.

However, the above scenario is the most simplified situation and will vary on your personal preferences.

It’s just to give you an idea of; how to calculate the total wattage and size of your RV generator correctly.

Note: Get a generator slightly bigger than your air conditioner power needs. I would suggest adding 20% to your total power needs.

This will make sure you have room to run other appliances along with the AC. Plus, prevent your generator from running on full load, increasing working life, and reducing noise and fuel consumption.

Other Factors to Consider when Choosing a Portable Generator for RV AC

Now you know what size generator is needed to run an RV air conditioner plus other appliances together. It’s time to look at the other deciding factors to consider before making a purchase.

Noise Level

Decibel Comparison Chart (Scale)

Going boondocking with a loud generator may prevent you from using the generator either due to campground restrictions or disturbed neighbors.

You need a portable generator that meets your power needs and be as quiet as possible. Though, generators designed for camping are very quiet. 

There are various ways to quiet your portable generator if you have a noisy one.

Choose an inverter generator and make sure to size your portable generator correctly.

In our reviews of the best generator for RV air conditioners, all the generators we recommend are quiet for their power output.

Fuel Efficiency

Knowing how much fuel your RV generator uses is an important deciding factor. You don’t want to go dry camping with a generator that needs to be refueled multiple times a day or hit the gas station to refuel.

Look for a portable generator that has the longest run time on a single tank of fuel. You can also opt for a dual fuel portable generator that will give you the versatility to use two different types of fuel.

Below you’ll find our recommendations of a few portable generators for RV AC that are very fuel-efficient in their respective power output.


Most RVers carry their portable generator on the back of their truck, which means you have to load and unload it physically. And buying a heavy generator will mean difficulty loading and unloading plus increasing the chance of back injury.

Therefore, size your generator correctly as an increase in the power output increases the physical weight of the generator.

If you need a bigger RV generator, then mounting the generator on your RV bumper will be a wise option.

All the portable generators we recommended to run your RV air conditioner come in the right weight to power ratio. Plus, they all have wheels and handle for easy towing.


The price of your generator is the ultimate deciding factor. Whether it’s the best generator for your RV air conditioner, it won’t go home until it meets your budget range.

One thing to note, however, is that the price of a generator is the direct indicator of its quality. 

Buy the most expensive unit you can afford if you’re a full-time RVer or go camping frequently. Seasoned dry campers will do fine with a budget generator.

One thing worth noting is that the price of your generator is not just what’s on the price tag. It will also include how much fuel it consumes and the overall maintenance cost.

The portable RV generator we have reviewed comes with a budget range from inexpensive to a premium budget range.

The 4 Best Generator for RV Air Conditioners

In this section, I’ll reveal why these are the best portable generator for RV air conditioners.

They will work well in any camping application. But, we’ll talk about how they perform with various size RV air conditioners and other appliances.

The generators reviewed below come in various price points, power different sized air conditioners, and are reliable.

Read on to find out reviews and ratings.

01. Best Budget: Champion 3800-Watt Dual Fuel RV Ready Portable Generator

Champion 3800 Dual Fuel Generator
Powerful enough to run a 15000 BTU AC and room for more
Runs on both LPG and gas, giving you versatility to choose between fuel type
Can keep you powered all night long with a single tank of fuel
The weight makes it unsafe to load and unload alone

Buying a powerful generator to run your RV air conditioner doesn’t mean you have to spend thousands of dollars. A budget-friendly option like the Champion 76533 Dual Fuel Generator can power your ac without breaking your bank.

To begin with, this portable generator produces 4750 watts of starting and 3800 watts of running power when run on gasoline. This is enough power to run a 15000 BTU RV air conditioner and still have room to run a few smaller appliances.

The option to choose between gasoline and propane hands you the freedom to use the type of fuel available to you. Moreover, propane burns cleaner has a longer shelf life, is cheaper, and requires less maintenance.

On a 3.4-gallon fuel tank, you’re looking at 9 hours of run time at 50% load and 10.5 hours on a 20 lb propane tank. The longer run time allows you to run your AC overnight without having to wake up to refuel in the middle of the night.

The noise level and weight are on a higher side, than what I would expect from a portable generator for camping. The unit comes with a variety of outlets, including a 120V 30A RV receptacle allowing you to plug in your RV without an adapter.

Other features worth mentioning on this budget portable generator are its built-in surge protector, a small display, and cold start technology. Plus, the generator is equipped with a low oil shutdown feature and is CARB compliant.

The downside to this budget generator is mainly its weight. With a dry weight of 119 lb, it may not be safe to load and unload alone. However, once on the ground, the wheels and handle allow easy tow around the campsite.

Overall, the Champion 3800 Watt Dual Fuel Generator is the most affordable camping generator on this list. It is powerful enough to power your RV, including an AC unit.

View the Champion 76533 PDF product manual here.

Noise Level: 68 dB(A) @ 50% Load | Dry Weight: 119 lbs | Output Wattage: 4750/4275W Starting, 3800/3420W Running | Fuel Tank Capacity: 3.4 gallons | Run Time/Tank: 9 Hours @ ½ Load

Read More: Here I have reviewed a few top-rated dual fuel camping generators that run on both gas and propane out of the box.

02. Best for 13500 BTU Air Conditioner: WEN 3800 Watt Inverter Generator

WEN 3800 Watt Inverter Generator
Can run a 13500 BTU RV AC unit comfortably with room for more
Extremely fuel efficient with a runtime of 8.5 hours or more depending on load
Super quiet operation allows you to run in the most congested campground
Difficult to lift in and out especially for elderly campers

Running a 13500 BTU RV AC unit means you’re looking at around 2800 surge and 1800 running watts. To make sure you have constant juice flowing, you need a powerful generator like the WEN 56380i Portable Inverter Generator.

This gas-powered inverter generator produces 3800 starting and 3400 running wattages. This means you have sufficient power to keep your AC unit running and room to run other appliances.

The generator with a full gas tank will run about 8.5 hours at 50% load making it very fuel-efficient. The eco-mode controls the motor speed depending on the load, thus preventing unnecessary fuel use and lowering noise levels.

This portable generator is especially loved by RVers and campers due to its quiet operation. At 57 decibels, you can confidently run it overnight, even in the most congested campgrounds.

This RV generator comes with features that are designed to reduce maintenance costs and frequency heavily. The fuel shutoff dries the carburetor and fuel line preventing fuel gumming. The overload protection, low oil, and fuel shutoff extend engine life.

This inverter generator produces clean power (THD < 1.2%), protecting your sensitive electronics from damage. This RV-ready generator comes with a 120V 30A receptacle and a digital fuel and loads display.

This is a parallel ready generator which means you can double the power by connecting two WEN generators. All you need is to buy the WEN GNA50i parallel kit.

Also, get the WEN 55201 magnetic dipstick to help extend the engine’s life. Additionally, make sure to follow the user manual to break in the generator correctly.

The downside to this generator is that it is on the heavy side for one person to lift it up and down alone. However, you have wheels and a foldable handle for easy roll around once on the ground.

Overall, the WEN 3800 Inverter Generator is a great choice for RV owners looking for a powerful generator to run a 13500 BTU AC unit plus more.

View the WEN 56380i PDF product manual here.

Noise Level: 57 dB(A) @ ¼ Load | Dry Weight: 99.2 lbs | Output Wattage: 3800W Starting, 3400W Running | Fuel Tank Capacity: 2.2 gallons | Run Time/Tank: 8.5 Hours @ ½ Load

03. Best for 15000 BTU AC Unit: Briggs & Stratton P4500 PowerSmart Series Inverter Generator

Briggs and Stratton P4500 Inverter Generator
Designed to power a 15K BTU RV AC unit and still has room to run other appliances
Can power your RV for up to 16 hours on a single tank at 25% load
The noise level is at an acceptable level
The weight can make loading and unloading it difficult

If you’re looking for a reliable source to power your 15000 BTU RV air conditioner then have a look at the P4500 PowerSmart Series from Briggs & Stratton.

This powerful inverter generator produces sufficient surge and rated watts to power your AC unit. Moreover, once the unit is up and running, you’re left with the power to run a microwave, refrigerator, and a few small items.

This portable generator can keep you powered for up to 16 hours at a 25% load on a single tank (3.4 gallons) of gasoline. This means fewer visits to the gas station and less fuel to carry for your trip.

The unit can be started either using the electric or recoil start. The electric start provides an easy start with a push of a button. However, the recoil starter hands you a guarantee that the unit can be started if ever the electric start fails.

The noise level on this inverter generator is at an acceptable level. The economy mode further subsides the sound and increases fuel economy by throttling the motor speed depending on the load.

Other features worth mentioning are its CO guard that shuts down the generator if the carbon monoxide level rises. Plus, a multi-functional display that shows the power usage, fuel level, and run time.

Additionally, this portable inverter generator comes with multiple outlets, including a 30A RV outlet.

The only downside, in my opinion, is its weight. However, the unit has wheels and a telescopic handle for easy towing.

Overall, if you’re looking for a powerful inverter generator that will keep your RV powered, including a 15K BTU AC unit, then the Briggs and Stratton P4500 is a good option.

View the Briggs & Stratton P4500 PDF product manual here.

Noise Level: 61 dB(A) | Dry Weight: 114.9 lbs | Output Wattage: 4500W Starting, 3700W Running | Fuel Tank Capacity: 3.4 gallons | Run Time/Tank: 16 Hours @ ¼ Load

04. Best for 2 AC Units: Westinghouse WGen7500DF Dual Fuel Portable Generator

Westinghouse WGen7500DF Dual Fuel Portable Generator
Enough power for bigger rigs with multiple air conditioners
Its fuel efficient whether you run on gas or propane
The key fob hands you the flexibility to operate it from the comfort of your camper
The sound and weight are what i don’t like about this unit

Bigger rigs need multiple air conditioners, and powering them simultaneously means you need a powerful generator. A portable generator like the Westinghouse WGen7500DF will make sure you have sufficient power to run both AC units along with other appliances.

To begin with, with a starting and running wattage of 9500 and 7500 when run on gasoline, you have enough power to run anything in your rig.

This is a dual fuel model that gives you the freedom to choose between gasoline and propane, depending on the availability. The easy fuel selector knob enables an easy switch between fuel types on the fly without shutting off the generator.

This generator is pretty fuel-efficient for the power it produces. It provides a run time of 11 hours on a single tank (6.6 gallons) and 8 hours on a 20 lb propane tank. This will ensure you can run both the AC units overnight without worrying about refilling.

Apart from the traditional ignition methods (recoil and electric), this generator comes with a key fob that enables wireless operation. This is especially important for those cold or hot days when you don’t want to get out of your camper to turn on the generator.

This generator comes with a few types of outlets but is not RV-ready. You need an L14-30R to a 14-50R adapter to connect to your RV.

At 72 decibels, the noise level of this generator is less for the power it produces. However, the noise level may be considered high for some campgrounds, especially if it is congested.

The downside of this generator is its weight and should be mounted on your RV.

Overall, the Westinghouse 7500 Dual Fuel Generator is a powerful machine designed to power the most demanding RVs with multiple air conditioners.

View the Westinghouse WGen9500DF PDF product manual here.

Noise Level: 72 dB(A) @ Load | Dry Weight: 192 lbs | Output Wattage: 9500/8550W Starting, 7500/6750W Running | Fuel Tank Capacity: 6.6 gallons | Run Time/Tank: 11 Hours @ ½ Load

How to Make Your AC Unit Generator Friendly?

It’s not about getting the biggest generator to run an RV air conditioner. It’s more about getting the right size generator and using it efficiently.

How efficient your generator runs while powering your AC unit depends on a variety of factors. 

Let’s briefly talk about them.

Before anything, add a soft start to your rooftop RV air conditioner. It will significantly reduce the energy needed to start the compressor, thus putting less stress on the generator.
Clean the air filters and the AC unit regularly. With time, the accumulation of dust in the air conditioner parts makes it run less efficiently.
Turn off all other appliances running on your generator before firing up your air conditioner. This will tax the generator less.
Don’t blast the air conditioner for short periods on full power to cool your coach quickly. This is bad for both your AC and the generator.
Use solar power to run other appliances during the day when your air conditioner is running. This will ensure you’re running your generator on lower loads, increasing fuel efficiency and overall life.

Being mindful of how and what appliances you use when you’re running your RV air conditioner will determine how efficient your generator runs. 

Running your RV generator at full load will not only reduce its working life but also increase fuel consumption and noise level.

Frequently Asked Questions

By now you know what size generator to run an RV AC unit. You have also seen my recommendation of the best generator for an RV air conditioner.

Now, let’s take a look at some of the most common questions regarding running RV air conditioners with a generator.

Will a 2000 watt generator run a rv air conditioner?

Yes, a 2000 watt inverter generator will run an RV AC unit. Not just any size, but it can comfortably run a 5000 BTU air conditioner.

However, the smooth running of a 5000 BTU AC unit on a 2000 watt generator depends on factors like altitude and temperature.

Your generator will perform poorly as the altitude increases. The same is true for temperature. As the temperature increases, your AC unit will need more power to maintain the desired temperature.

Read More: Is a 2000-watt generator enough for my RV?

Can you run an RV Air Conditioner on 15 amps?

Yes, you can run an RV air conditioner on 15 amps, but you need to have the right size AC unit and right gauge wire.

According to Watts Law, the total wattage produced by a 15 amp outlet is about 1800 watts (watt= amps * volts). Now you need to have an air conditioner that uses less than that.

On the other hand, running an AC unit on a 15 amp connection with a lower gauge or quality may increase the risk of fire.


There are many types, sizes, and brands of generators and RV air conditioners on the market. What size generator you need will depend on the size of your air conditioner and other appliances you wish to use simultaneously. 

My advice would be to find out your total power needs accurately and then settle on a generator.