18000 BTU RV Air Conditioner: How Many Sq Ft And Generator

Some owners have not heard of a rooftop 18,000 BTU AC unit for an RV. That may be because the units we saw were all window installed. They can cover a large area but given the number of walls inside an RV, you may need fans to share the cool air.

Running time watts for this unit will be 1800 but start-up watts are going to be huge. You need a generator that can handle 4500 watts of starting power when you turn this unit on. More power means you need to have a generator with lots of power.

To learn more about this air conditioner size, just continue to read our article. It has the information you need to make sure you buy the right AC unit for your RV or trailer. Sometimes more power is not the best option

18000 BTU RV Air Conditioner


We did not find a rooftop AC unit for RVs that measured 18,000 BTUs. We did find those new model designs that go on a wall. The majority of these units are window designed.

We did not find a rooftop model at all but there may be some available. The average square foot rating for this size of the air conditioner is 1000 square feet. That would cover most RVs made today if you could disperse the cool air easily.

Different appliance manufacturing companies make this size of the air conditioner. But just about every model we saw was window installed. There were no rooftop options available so you would lose a little light to accommodate this unit.

All the ones made for rooftops stop at 15,000 BTU. 13,500 and 15,000 BTU units seem to be the standard size for RV rooftops. The window size you will need to hold these units will average about 20 inches by about 31 to 42 inches.

Shopping around will help you find the right price as well as find one that is small enough for your RV or trailer’s windows. Just watch the depth of the unit as you do not want it sticking out too far.

How Many Sq ft Does An 18000 BTU AC Cool?


The average room rating is 700 to 1000 square feet. When you compare this rating with the size of most RVs or trailers, then it is easy to conclude that they will cool every nook and cranny in your RV.

How much coverage you get will depend on the floor plan of your RV or trailer. Many are one room but there are also many with several walls and doors to consider. This unit will keep certain areas inside your RV nice and cool but other areas may need a little fan assistance to spread that cool air around.

The rating and power are there for an 18,000 BTU AC unit. The practical use may not be there. You may be better off with 2 13,500 BTU rooftop units or 2 15,000 BTU rooftop AC units than 1 18,000 BTU AC unit.

More power does not necessarily mean you get better coverage or even coverage. There was a television show called Home Improvement where the star always wanted more power.

That desire works in the t.v. world but not in the real world. Think this through carefully as you have to consider the power demand and if you can use the other features at the same time you use the larger more powerful air conditioner.

How Many Amps Does An 18000 BTU Air Conditioner Pull?

Depending on fan speed and cooling temperature, this unit can pull between 13 to 20 amps approx. This rating is for the window, portable, and split versions of this type of air conditioner.

The equation you need to use to find the number of amps it will use is BTUs divided by watts = amps. Or if you want to find the number of watts it will use then the equation is volts x amps = watts.

At any rate, you will need a powerful generator to make sure there are no hiccups when you turn that big AC unit on. When you go shopping, compare these stats with the lower-producing AC units and see if this is the best option for you.

Here is a little chart to help you when you do this comparison:

AC Unit Capacity Number of Amps Type of AC Unit
5000 BTUs 3.62 – 5.43 Window
6000 BTUs 4.35 – 6.52 Window
8000 BTUs 5.80 – 8.70 Window & portable
10,000 BTUs 7.25 – 10.87 Window & portable
12000 BTUs 8.70 – 13.04 Window AC, Portable AC, Mini-Split
13,500 BTUS 12 to 14 Rooftop
15000 BTUs 10.87 – 16.30 Window & portable
18,000 BTUs 13.04 – 19.57 Window AC, Portable AC, Mini-Split AC

Information for this chart came from https://learnmetrics.com/how-many-amps-does-do-air-conditioners-draw/ & https://thecampingadvisor.com/how-many-amps-on-a-13500-btu-air-conditioner/

What Size Generator Do I Need To Run An 18000 BTU Air Conditioner?


The starting amps are the biggest concern you will have. It is said that this size of AC unit will need 1800 watts of power to run efficiently. If that was all you would need to worry about then you could get away with using a 3000-watt generator.

However, starting power is the main concern, and to get this big AC unit up and running, you would need 4500 watts. But a 4500-watt generator may not be large enough as you probably have other electrical items running at the same time.

It would be best to go with at least a 5000-watt generator or larger. It is not just the air conditioner you have to worry about. You have to factor in your toaster, hair dryer, lights, radio, television set, and more.

Once you have added up all their start-up and running watt demands, then you can pick out a large enough generator to handle the load. Don’t forget, if this generator is not built-in, you will need storage space to hold it when the generator is not in use.

RV Air Conditioner 18000 BTU Options


Here is a list of different manufacturers and their best models for this size of the air conditioner. Keep in mind that these are going to need at least 230 volts to run properly.

1. LG 18000 BTU 230V- this is a Korean company and it comes with a stellar reputation. The unit can cool 1000 square feet and it saves you money. The energy star rating makes sure this unit uses 25% less power than normal. A built-in inverter is an added plus.

2. Amana AMAP182BW- This is said to be a very reliable AC unit, one that will last a long time. It is a heavy-duty model that handles almost every imaginable weather condition you run into. The unit comes with a universal window attachment system making it easy to install in your RV.

3. OLMO Mini Split AC- best for those smaller RVs that don’t have a lot of space. The unit is easy to control as it comes with remote operation. Plus, it is supposed to be very quiet so you can get some rest at night.

4. Frigidaire FHWW183WC2 - The slide-out chassis gives you a more cooling option. Plus, it is designed as a smart air conditioner giving you lots of freedom when you want to change the settings or turn the device on or off.

What is The Largest RV Air Conditioner?


RecPro 12V RV Air Conditioner is said to be 20,000 BTUs and that seems to be the largest option you can buy. This is a rooftop model that only weighs 90 pounds. It is also supposed to be very quiet when it is turned on.

Keystone is said to make a 25,000 BTU unit but like the 18,000 BTU option, it is a window-only installation. This unit is rated to cool 1500 square feet and has a built-in thermostat.

While it is perfect for homes and apartments, you may need to do some special upgrading to get it to work in your RV or trailer.

The Friedrich KCM18A30A is a 20,000 BTU model and it is a window installation only as well. Finally, there is the Cooper & Hunter 24,000 BTU, SEER Ductless Mini Split AC/Heating System.

You do have your choices but in many cases, these larger units may be overkill.

Some Final Words

When you do not feel like your current air conditioner is doing its job. You can look at these more powerful units. They are designed to cool large areas which makes them ideal for mid to larger-sized RVs or trailers.

But do some comparisons as most owners are content with their 2 13,500 or 2 15,000 BTU units that provide very even cooling on hot days. The demand for that extra power will raise your electrical costs so consider all factors before leaping to a more powerful AC unit.

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