How many watts should the generator be to run RV AC?

In this blog post, we will answer the following question: How many watts should the generator be to run RV AC? We will explain how an RV generator works and how much power you need to operate an RV air conditioner. 

How many watts should the generator be to run RV AC?

You should have at least a 2000 watt capacity  (preferably a 4000-watt capacity generator to run an RV AC. Of course, the capacity of your generator will greatly depend on the size and type of the RV, and on the size and type of the AC. 

To understand what generator you need to run an RV AC, you also need to know about BTU. What is BTU? BTU stands for British Thermal Unit which is a unit measuring the amount of heat used to raise the temperature by one degree F ° of a volume of water: 3414 BTU = 1000 W (1 kW).

Here is a simplified table to help you understand the sizes and types of RVs, what is the best AC for a specific model and how much Watts should the generator be: 

Vehicle typeVehicle length Air conditioner power in WProduct example
Converted van Up to 19 ft1000 to 1800W Dometic FreshJet 1100
Converted van 21 ft or more2000 to 2500W Webasto Cool Top Trail 20;
Dometic FreshJet 2200
Motorhome Up to 19 ft1000 to 1800WDometic FreshJet 1100
MotorhomeFrom 19 ft to 23 ft2000 to 2300W Webasto Cool Top Trail 20; 
Dometic FreshJet 2200; 
Dometic FreshLight 2200
MotorhomeFrom 23 ft to 26 ft2400 to 3000W Webasto Cool Top Trail 24
MotorhomeMore than 26 ftMore than 3000WDometic FreshJet 3200; 
Webasto Cool Top Trail 34
Travel Trailer Up to 19 ft1000 to 1800W Dometic FreshJet 1100
Travel TrailerFrom 19 ft to 23 ft2000 to 2300W Webasto Cool Top Trail 20; 
Dometic FreshJet 2200; 
Dometic FreshLight 2200
Travel TrailerFrom 23 ft to 26 ft2400 to 3000W Webasto Cool Top Trail 24
Travel TrailerMore than 26 ftMore than 3000WDometic FreshJet 3200; 
Webasto Cool Top Trail 34

How does the RV generator work?

The generator in an RV basically consists of an electric winding driven by an internal combustion engine, diesel, gasoline or gas, capable of producing alternating current. The type of fuel will be determined primarily by the fuel used in your vehicle’s main engine. In the case of caravans, a very popular option is those fueled by propane gas.

If you have a 30 amp electrical system in your motorhome you can basically use 3,600 watts before exceeding the capacity of the electrical system. 30 amps x 120 volts = 3,600 watts. This is why manufacturers of motorhomes with 30-amp electrical systems equip them with 4,000-watt generators. RVs with 50 amp electrical systems are equipped with larger generators.

Motorhomes with 2 air conditioners up to 15000 BTU can be equipped with an 8000-watt generator to supply all the consumption on board, although it is true that the dryer or the washing machine cannot be used with both breaths of air on. RVs with three air conditioners typically have a 10,000-watt generator.

How to choose a generator for an RV?

When choosing a generator for your RV, you need to think about the type and size of the vehicle, but also on how many appliances are on board. For example, teardrop trailers and pop-up campers may not require a generator at all, relying on tow vehicles to power devices and run the pump.

However, for RVs with few devices such as microwaves and coffee makers, or with an AC unit, a generator is a must. But how do you know what size generator you need for your RV? Let’s take a closer look and find out.

How much electricity can an RV use?

Individual automobiles have different requirements, depending on their size, insulation, year and horsepower demand. The normal RV uses around 20 kWh per day and 608 kWh per month.

The biggest decision regarding the size of generator you need for the motorhome is your air conditioner energy requirements if you have one. Air conditioners have huge starting power requirements, which can consume all the energy available from your own generator for a short time.

  • Many popular RV generators have been listed for 3000 or 3000+ watts. These generators will start an air conditioner and, after it starts, allow you to run some low energy products.
  • Large container generators are generally rated for 4500-6000 watts. These generators will allow you to start an air conditioner when you are using different things and provide a lot of energy for cooking and cleaning.
  • You can also consider choosing two small generators, rated at 2000-2200 watts each. When connected in parallel, they allow you to start a huge air conditioner, as well as remaining electricity for different devices. The practical thing about this alternative is that it allows you to eliminate one generator and travel lighter during the seasons once the air conditioner is not needed.

RV AC: How does it work?

All RVs air conditioners on the market operate on 230 V and use the same technology as domestic refrigerators: the compressor. To put it simply, a gas (refrigerant) is compressed (a compressed gas heats up) then sent to a copper network. The gas will relax there and therefore cool down: it’s done, we’re cold! 

A fan system will “push” air which, passing over the pipes, will cool before entering the passenger compartment. Compressor technology offers the advantage of being very reliable and very efficient.

What types of air conditioning for RVs and how to choose?

There are two types of air conditioners on the motorhome market: roof air conditioning and trunk air conditioning. Their performances are identical, their mode of operation also; what changes is the installation. The vast majority of air conditioning in motorhomes is installed on the roof: it is simpler and more economical.

Choose the trunk air conditioner when there is no space on the roof or unnecessary large storage boxes (rather rare in a recreational vehicle).

  • Reversible air conditioners for winter use: If you go on vacation to the mountains in winter with your motorhome, some models are “reversible” and work as a heat pump to act as heating inside your vehicle. This is the case with the DOMETIC Freshjet 2200 for example, it works well and it is perfect for winter camping.
  • Battery-powered motorhome air conditioning: Does a 12 V battery-powered air conditioner for motorhomes exist? No, an air conditioner is a very powerful electrical equipment (from 1000 to 4000 W on average) and the operation on 12V is in fact very complicated. 

Also, it is not possible to use an air conditioner when stopped via the 12 V batteries of the motorhome, even with lithium, the autonomy would be a maximum of one hour; not enough to be effective.

On the other hand, some manufacturers offer 12 – 230 V current transformation solutions to use the air conditioning of the motorhome while driving, this is possible because the engine alternator can cover the consumption of the device. This is the case with DOMETIC, which offers DC KIT DSP-T 12 kits that allow its air conditioning to be supplied with 12 V.

So it’s clear, your air conditioner will only work with 230 V so when your vehicle is connected to a 230 V terminal or socket.

The bottom line

Choosing your RV generator is not complicated at all. You just have to estimate the daily consumption of your appliances and multiply it by the number of days you plan on traveling. If you want to know more about RV ACs or RV generators, check our other articles on the same subject!

If you have any questions or comments on this content, please feel free to get in contact. 

FAQ on How many Watt should the generator be to run RV AC?

How long does an RV AC last?

An RV AC can last up to five years, all depending on how often you use it, how well you maintain it, and whether you recharged it with Freon or not. To make sure that your RV AC lasts for as long as possible, you must maintain it well. 

What air conditioning to choose for an RV?

When choosing air conditioning for an RV, take into consideration the following:

  • Telair Air Conditioner Silent 500H.
  • Aventa Comfort.
  • Airva 12V & 24V.
  • Dometic Freshlight 1600 & 2200 air conditioner.
  • Portable air conditioning SW Cube.
  • Kronings Rooftop Air Conditioner K2400.
  • Euromac AC2400 Split System.
  • Telair Silent 220V-8400H.

Can I run my RV generator all night?

Yes, it is possible to run your RV generator all night, but the type of generator you have will determine how long the fuel will last. On average, an RV generator can last from 8 to 20 hours.


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