How Do RV Air Conditioners Work?

The vast majority of vacationing RV enthusiasts hit the road in search of sun, fun and adventure, with an emphasis on the sun. Some hardy souls do enjoy heading old in their rig when the temperatures are lower, and those who choose to make an RV their permanent home may have no choice but to endure some cooler temperatures, but most of us prefer RVing in warmer locales. This does mean that an RV air conditioner is something of a must. But just how do RV air conditioners work?

In basic, but technical terms, an RV air conditioner removes heat from the air inside your RV. The air conditioner pulls in hot air, expels it outside the RV, and then pushes cool air back in through air vents.

How Does an Air Conditioning System Work in an RV?

How Do RV Air Conditioners Work
RV maintenance is vital if you want to remain cool all summer long.

The RV air conditioning system is a closed system, unlike the air conditioning in your home. This means that the refrigerant fluids are sealed inside the tubing with no way out. They cycle through the system on a regular basis, expelling hot air and pushing cool air back into your RV.

Inside the AC unit, the compressor circulates, heats, and compresses refrigerant vapors. The vapors will give off heat in the condenser when they are pressurized to a high enough pressure.

The condenser extracts heat from the air and expels it from the RV. The refrigerant vapors are cooled and turned back into a liquid inside the condenser.

This cool liquid makes its way to the evaporator, which absorbs heat from the hot air inside the RV. The temperature of the air drops as the hot air is washed over the cool evaporator coils. This cool air is then blown back into the RV, cooling it – and you – down as it does so.

Most RVs come with an air conditioner mounted on the roof as standard. Longer vehicles – over 32ft – usually have two units, as one is usually not enough to get the job done efficiently. If your RV is an older model and did not come with a roof A/C you may be able to get one installed. Alternatively you might choose to make use of a portable air conditioner designed for home use, which is not the best option by far but would work in a pinch, as we’ll discuss later.

5 Tips To Help Run Your RV AC More Efficiently

The one thing that you do need to understand is that no RV air conditioner is going to work as well as that big unit you might have at home, or even the powerful A/C you might have in your car. Most do a decent job in temperatures under 100 degrees though.

You also need to be aware of the fact that running your RV’s air conditioning system is going to use a significant amount of energy, something that’s true of all air conditioners. There are, however, some things you can do to help save energy – and therefore money – and help your RV air conditioner run more efficiently at the same time. Here’s a look at five of the most effective:

Keep Your RV Air Conditioner’s Filters Clean

As is the case for your home HVAC system, it’s crucial that you keep your RV air conditioner’s filters clean and lint free by keeping them clean and replacing them on a regular basis.

A dirty air filter will not only make your unit work a lot harder to get its job done, thus using more energy and reducing its useful life, but it will also mean that the filtered air is not as clean as it could be, resulting in poorer air quality inside the RV itself, something that can be bad for you and your family’s health.

Ideally you should check, and clean, your RV air conditioner’s filter after every trip, and replace them according to the manufacturer’s instructions, usually every 6-12 months.

Don’t Leave the Doors Open

If you leave any of the doors – or windows – to your RV open when using its air conditioning system you will only make it work harder, and significantly decrease its efficiency, by letting in hot air that need not be there.

In addition to keeping doors and windows closed when the A/C is on, consider improving the insulation around the doors and windows – simple weather-stripping usually suffices – to keep more of that nice cooled air inside where it belongs.

Make Use of Fans

The air in front of the vent in an RV air conditioner tends to be the coldest, creating a pocket of cool air. Ceiling fans, or even simple freestanding fans, can assist in dispersing that cool air throughout the space and lowering the temperature faster, meaning you’ll stay cooler and your air conditioner won’t have to work as hard to achieve that goal.

Keep Heat Creating Activities Indoors to a Minimum

The more heat you introduce into the interior of your RV the harder your AC will need to work to cool things down. If you cook indoors – even if you are only using the microwave – you’ll introduce hot air, and the same is true of taking a steamy shower.

When it’s hot enough that you need to run your air conditioner try to limit cooking activities to outdoors – BBQs are more fun anyway – and take cool showers, which will help keep you cooler anyway. And when you can, park in the shade.

Consider an Energy Efficient Portable A/C

If there are areas of your RV that the air conditioning just does not seem to cool you could consider occasionally running an energy efficient portable A/C unit instead. Just be aware that this is best done only when you are able to hook up to shore power, as these units will quickly drain your battery if you are not.

Energy Star rated portable air conditioners are getting cheaper, and as long as you have a window that it can be vented through you can make use of one almost anywhere in your RV.

RV Air Conditioning FAQs

What do RV Air Conditioners Run On?

It does depend on the type of RV air conditioner you have. The vast majority of rooftop RV air conditioners contain a refrigerant and operate in a very similar way to your fridge. They are powered by electricity, from a separate circuit in your RV called A/C power.

This means that they can be operated in the same way as any other electrical component in your RV: via shore power, generator or straight from your vehicle’s battery. The former is the cheapest and most efficient of course.

RV Air Conditioner Not Blowing Cold Air

If your RV AC unit isn’t blowing  cold air, check the RV thermostat and the electric system powering it.

Things like a loose wire or a low battery might be the cause behind the thermostat turning the system off.

If there is no noise coming from the RV AC unit, it could be that the controls are not receiving enough power.

The capacitors of the fan may need replacement if the compressor starts slowly, blows out air weakly or blows only warm air or if lights dim when it runs.

Other common reasons why your RV AC’s isn’t giving you enough cool air:

  • Low Freon levels
  • A dirty compressor
  • Problems with the fan.

Can I Run My RV AC All Night?

You could, and if you are on shore power it might be tempting to do so. However, as these units are energy guzzlers that may not be popular – or even allowed – at certain campgrounds, or it may cost you more. If you are using a generator, an A/C will deplete it very quickly. And it will flatten your battery quickly too, if it will even work on battery power, as many RV air conditioners just draw too much power for that to be possible.

Try to make use of fans at night instead, and take care to seal in as much cool air as you can in the day that they can circulate at night.

Do RV Air Conditioners Need to be Recharged?

If your RV air conditioning unit makes use of a refrigerant like Freon – and many do – it will eventually need that recharged. If your A/C is not working as well as it used to, the refrigerant level is the first thing you should check. When you do need a ‘top up’ that can be done relatively easily in most cases, either by doing it yourself using a prepurchased bottle or having an auto shop do it for you.

Can You Run an RV Air Conditioner While Driving?

It’s doubtful that it will even be possible for you to do so. As we mentioned earlier most RV air conditioners are just too powerful to run on battery power. And even if you could, you might not get too far before your RV’s battery is drained, and you come to a grinding halt.

Some newer RVs do have a dashboard A/C very similar to a car’s and those can be operated while you are driving. Doing so will increase your gas consumption though, just like it does in your car.

Is It Better to Keep Doors Open or Closed for Air Conditioning?

Always keep doors and windows closed when you are running your RV air conditioner, without exception. As we mentioned earlier, if you don’t, you will be defeating the point of having it running if you don’t, by inviting all that nasty hot air in.


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