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How do RV AC Units Work and What Size of AC do you Need for your RV?

Updated: Jun 27, 2023

Learn how your RV AC keeps your motorhome cool during the hot summer months. Find out what size of AC is perfect for your RV.


The details of an AC unit might not be the first thing on your mind when you are buying an RV. But if you are a devoted RV camper who spends most of their summer on the roads, an AC is a necessity.

Since all RVs and motorhomes operate differently, it is always best to do your homework before you head out on your journey. After all, no one wants a faulty air conditioner in the blazing summers. Of course, it is equally important to maintain your RV appliances so that it keeps running smoothly for a long time. So if you are a newbie summer camper, or are particular about keeping your RV appliances in good shape, read on to know all about RV AC units and how they work.

Types of RV AC Units

Size, space, and parameters are crucial to all RV appliances because of limited space. Before you head out to buy your AC unit, make sure you know how much space you are working with. After that, it is time to determine the best type of unit for your vehicle, of which the main types are ducted and duct-less units.


Ducted RV AC unit

Ducted RV air conditioning systems are used in motorhomes that have multiple ducts in the ceiling. This allows the RV to operate more than one AC unit, distributing cool air through the walls, ceilings, and floor. Because they provide more consistent cooling service throughout your motorhome, ducted units are more expensive. They are also quieter when running.


Ductless RV AC unit

Ductless units are used in smaller RVs. They are usually installed in a window, a wall opening, or on the top of the RV. Ductless units operate by simply blowing the AC's cool air out of the unit's bottom vents to cool a room. Their vents are directional and easy to use. Common ductless units include the under-bench, RV window AC units, or rooftop air conditioning systems. The smallest RV AC units are usually ductless in nature.

Parts of an RV AC Unit

parts of an RV AC unit

An RV AC unit consists of a compressor, condenser, evaporator, wires that connect the parts together, an air moving system, a fan to push the air over the condenser, and another to push air over the evaporator.

How do RV Air Conditioning Units Work?

RV air conditioners operate by removing heat, not by creating cold air. This is done by a closed air conditioning system comprising several parts that work in a precise order.

  • First, the compressor works to circulate, heat, and compress refrigerant vapors in the air conditioning unit. The vapors are pressurized at a high level to give off heat in the condenser.

  • The condenser then takes the heat out of the air and pushes it out of the vehicle. The refrigerant vapors are cooled down in the condenser to be turned back into liquid form.

  • The evaporator welcomes the cool liquid from the condenser and absorbs all the heat from the RV’s warm air. This makes the liquid expand, and once the liquid absorbs enough of the RV’s heat, it becomes vapor again.

  • The overheated vapor will be sucked into the compressor, and the cycle will repeat.

Here is a video explaining the process.

What Do RV Air Conditioners run on?

Just like the RV itself, the air conditioning units also take up a lot of energy to run. Unlike RV refrigerators, it is not easy to run an RV AC unit on propane. While it would be possible, its logistical setup is slightly more complicated and it will also be more expensive. Instead, your best bet is to run your AC unit on a special generator feature called ‘AC power’ from a 120-volt socket in sources like home electricity and portable generators. Another alternative is to run your AC unit on gas generators, but this will be costly to refill time and again. Full-time RVers can also consider investing in solar panels to run their units on solar energy, but it is a hefty up-front investment.

How Well Do RV Air Conditioners Work?

It’s important to have realistic expectations for your RV AC unit because it simply cannot perform as efficiently as a home AC unit. Regardless, it does help in cooling down your motorhome. According to experts, an efficient RV AC unit should output air that is anywhere from 16 to 22 degrees cooler than the air coming into the AC unit.

How Long do RV Air Conditioners Last?

The life expectancy of an RV AC unit is dependent on three factors: how hot the weather is when the AC is running, how often it is used, and how durable your particular unit purchase is. If maintained well, then your AC unit can run for several years comfortably. Read on to find out how you can maintain your RV AC unit.

RV AC Unit Maintenance Tips

RV AC maintenance tips

Clean the Filters:

Proper airflow is key to your ACs running efficiently. The filters in air conditioners help in removing particles from entering the condenser. If your filters are dirty, then the airflow to the condenser will be slowed down, and the cooling process too


Clean the Exterior Air Exchanger:

The exterior air exchanger is a set of cooling fins outside that a fan blows air through to reject heat. If these become clogged, the AC becomes less efficient. It is ideal to check the exterior once a year.

Insulate the Doors and Windows:

Doors and windows are the number one source of letting heat into your RV during the summer. Be sure to keep both closed and install window curtains.

Block the Sun with Shades and Awning:

Shading is a great way to reduce the heat and temperature inside your RV. During peak sun hours, use your RV’s awning to shade the exterior. You can also use Reflectix material on doors or windows or RV window sunshades to prevent any heat from entering the RV.

What Size of AC do you Need for your RV?

The size of your air conditioning unit will depend on the size of your RV. The measuring unit for air conditioning is BTU, and the more the BTUs, the greater the power of the AC. RV air conditioners usually fall between 11,000 to 15,000 BTUs. Therefore, the longer the RV, the more BTUs needed to cool down. This is why longer RVs that are over 32 feet use two AC units to combat summers. An even larger RV, such as a toy hauler, may need a third AC unit.

Can I run my AC all Night?

Sure, you can run your RV AC all night. You can even use it all day if it’s very hot. However, keep in mind that your AC will use up quite an amount of energy, and running an AC for a long time, or multiple ACs, will hook you up to a pretty gas bill too.

Keep Cool!

There you have it, a full guide on RV air conditioning units just in time for the summer! The warmer months are peak traveling season and intense heat can make any trip go south quickly. Use this guide to choose the best AC for your RV and maintain it for years to come, so that all your warmer holidays go by in a breeze!



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