RV Air Conditioner – The Rooftop, Slim Add On…

RV Air conditioner is used on recreational vehicles (RVs), or on boat roofs (also known as rooftop air conditioner).

Frankly speaking, it belongs on land, and in water… I mean “on” water.

I park it under Marine ACs, just to give it a home of some sort.

O.K. Let’s get on to the…


One important thing to note about RV air conditioners is, manufacturers hardly give out the details of the EER, and SEER values of the unit.

Maybe because we hardly use it. Yes, that makes sense – at least to the masses of air conditioning users.

However, you can still evaluate the EER value using this simple relationship:


Btu/hour ÷ watts of required electrical power input

That is one of the most important criteria that you have to use in selecting a range of RV air conditioners.

There is more to a rooftop air conditioner;

  • all rooftop air conditioners are air cooled

  • your cooling (and/or heating) option for rooftop ACs ranges from, 5,000 Btu/hour to as large of 15,000 Btu/hour.

    So, you can cool an approximate area of 10 feet by 50 feet of a recreational vehicle, or boat

  • weight of this unit will be around 100 lbs (or 45 kg). So, installation must be performed by least 2 persons

  • the overall design is wide, and short, forming an aerodynamically shaped structure.

    Very useful for lowering air resistance while in motion.

    Manufacturers will have two shroud height types of an RV AC. The normal height, and the slim, or low profile type

  • width and length of these units is normally 14 1/4” by 14 1/4”, to accommodate for standard vent opening of an RV, or boat roof

  • rooftop air conditioners are designed with cooling only, cooling with optional heating through a heat strip, and air conditioner with reverse valve – to act as a heat pump.

    Heat strips are normally sold separately, to the air conditioning unit

  • hang on, you can’t just cool, or heat space using mechanical air conditioners, as there are RV evaporative coolers, useful in dry, and warm climates.

    But that is not the main topic here. It belongs somewhere else. However, it is good to know the options you have for marine air conditioning

  • you will often find manufacturers quote rooftop air conditioners with ducted, or non ducted term.

    Ducted RV air conditioners (or rooftop ACs) have air registers separate to the air conditioning unit.

    Non ducted units have all, in a single shroud unit.

    Choose the former setup if your room is quite large, and the latter for small rooms

  • covers are available for these units, should you wish to store it for a long period

  • rotary, or scroll compressor is used for this air conditioning unit

  • accumulator, will be an almost standard installation to the unit – as you can perform pump down operation easily

  • there is a minor drawback to RV air conditioners, where a substantial number of those, come with a mechanical, or manual thermostat

  • important fittings are made of corrosion resistant material, and the drain pan is made of plastic material.

    I find this feature very useful, especially when exposed in salt-saturated, warm and moist air. The perfect combination for rust :-)

  • if moist air is an issue with air conditioning on water, then bacteria will also be an issue, and hence the need of non organic filters – to prevent “healthy” growth of unwanted neighbours

Over to…

Power supply for RV air conditioners:

You have two options;

  1. using direct power supply if you’re docked at jetty, or parked in a campsite

  2. or using a generator. It is good to oversize the generator by 19% to the actual power requirement of the RV air conditioner


Detailed installation procedure for an RV air conditioner (or rooftop unit), varies from a manufacturer to another, but the general installation techniques should follow the following steps,

  1. make sure that you have provision to place the AC on your roof.

    I don’t think that this should be an issue, as boats, and recreational vehicles come with this feature as standard

  2. sketch, and prepare power supply route (from generator and/or power socket) to the RV air conditioner location

  3. size and select the air conditioner, as per your requirement.

    Make sure your AC can fit in the roof opening

  4. install the air conditioning unit snugly within the available space,

  5. install the generator at designated space in your boat, or RV,

  6. complete the installation through completion of wiring, and testing.

    NOTE: Do not perform wiring tasks if you’re not qualified to do so. All wiring should be performed when power supply is isolated

So, do you need it?

RV air conditioners have a good range of cooling, and heating capacities for marine, and land use. Additionally, these units can cool, or heat, or provide evaporative cooling options – depending on the design.

It is placed on top of the roof, where air supply can be distributed evenly in a small space.

Installation is relatively easy compared to compact marine air conditioner, or 12 volt air conditioners, as it is air cooled.

Please bear in mind that your budget, should also include provision to buy generator. So, the complete unit will cost approximately 2 times more than a home portable air conditioner – size to size.

If you ask me, I would say that RV air conditioner (rooftop AC) is amongst the popular choice for you, if you own an RV, or you go on semi-regular boating trips.

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