13500 BTU vs 15000 BTU: Differences Between 13500 And 15000

Trying to stay cool... It is a struggle to stay cool at times when the temperatures reach 110 degrees F. But a more powerful AC unit can help with that struggle. They do not use that much more power but the extra cooling may be a welcome relief.

There is about a 1500 BTU difference between the two cooling units. You get that much more help on a hot day. However, on really hot days, the 13,500 BTU unit will not work that well if the 15,000 BTU unit is struggling to keep the RV cool. That is the main difference between the two.

To learn more about this topic just continue to read our article. It has the information you want to know about so you can pick the right AC unit for your RV situation. Keep in mind that unless otherwise noted, we are only talking about AC units.

13500 BTU vs 15000 BTU

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The difference between 13500 BTU and 15000 BTUIt is a known fact that you will get more cooling power with the latter unit. The good news is that you may not draw more power with the upgrade. Some owners have reported only 1 amp more usage while others have said they draw the same amount of amperage.

The key difference between the two is that the 15,000 BTU unit will have a little more cooling power than the 13,500 BTU unit. That means that on those very hot days, your RV should not be too warm.

What is the situation that gives you a clear view of the difference is that if the 15,000 BTU unit is having a hard time keeping your RV, etc., cool, the 13,500 certainly won’t do the job.

You have to take into consideration the number of hot days you will have to endure and their temperature levels. If the 15,000 BTU keeps you cool on those days, there is no guarantee the 13,500 won’t struggle. It may handle the job but you never know.

How Much Space Will a 13500 BTU Cool?

The charts all say different figures but they are also very close to one another. The lower boundary marker is anything under 400 square feet. It will handle all small trailers and RVs for you with ease and may be overkill.

The 13,500 BTU AC unit is rated for between 500 square feet and roughly 700 square feet. If your RV or trailer is 30 feet long and 8 feet wide, this AC unit should be more than enough to keep your trailer cool.

However, when you experience extremely hot days, even that size of the trailer may get too hot for your AC unit to cool. This has been the experience of many owners and they have often upgraded to a 15,000 BTU AC unit to handle the extra heat.

How well your 13,500 unit works will also depend on how well your RV or trailer is insulated. A badly insulated RV lets the cold air out quicker than you can put it in. Just make sure your RV or trailer, etc., is well insulated.

What Size Room Will a 15000 BTU Air Conditioner Cool?


This type of AC unit will handle roughly 700 square feet and under. It would definitely be overkill if you put this unit in a very small RV or trailer. To give you some idea of the difference between AC units, a 17,000 BTU AC unit handles 800 square feet and under.

But these are all ballpark figures as every chart seems to have a different rating for these AC units. The thing to do is talk to the dealer specializing in RV AC units and get their actual rating.

You shouldn’t have much trouble with either of these AC units as the average size of an RV or trailer is around 500 square feet approx. Many of these units come with 2 AC units so you should be covered no matter how hot it gets outside.

The key is to make sure you can draw the appropriate amount of power to run both at the same time when needed. The start-up power will be your main problem running both at the same time.

Quick Comparison Cart

The following table will give you an idea of how big your RV or trailer has to be to use either the 13,500 or 15,000 BTU AC units:

Square footage BTUs
100 5,000
200 7,000
300 9,000
400 10,500
500 11,500
800 17,000
1000 21,000

Keep in mind that all charts are approx. And this is placed here to get you started thinking in the right direction. There will be a difference in square footage coverage so keep that in mind as well.

Also, make sure you factor in where you will be camping. There is a difference between using a generator, 30 amp power, and 50 amp service.

How Big Of a Generator Do I Need To Run a 13500 BTU Air Conditioner?


This is a very important question as when you are out boondocking, you do not want to run short of power when it gets hot. The approx. Starting power for this type of unit is 3,800 watts.

The approx. running power needed is 1300 watts (this depends on the make, brand, and model). Your generator has to be strong enough to handle both demands and put out the power needed.

Some units say the starting wattage is only 2000 watts and the running wattage is 1500. Either figure means that you would need about a 3000-watt generator to handle the two demands safely.

Keep in mind that your generator may not be able to handle the start-up wattage for 2 AC units. If you try, your generator may throw a breaker or blow a fuse. Also, when you are running your AC unit, you may not be able to run other electrical devices and appliances.

When shopping for a generator, you need to keep those facts and figures in mind. Get one that is too small and you will only be able to run the AC unit or the microwave but not both at once.

How Much Power Does a 15000 BTU Air Conditioner Use?

The biggest difference between the 13,500 BTU unit and the 15,000 BTU unit will be in start-up power. The latter option requires 3500 watts to start and that is about 800 more than the former unit (we told you the charts were all different).

For running power, the 15,000 BTU unit requires about 1500 watts, which is, as you can see, a slight difference between the lower BTU model. Some owners have stated, that the 15,000 BTU AC unit only uses 1 amp more than the 13,500 BTU unit.

What that tells you is that not only are the charts approximations but that different brands, models, and makes need different levels of power. They are not all going to be rated for the same power draw.

You have to compare the different brands, makes, and models to make sure your generator will produce the power the device needs to work at optimum levels.

Should I Upgrade My 13500 BTU AC For a 15000?


This decision is really up to you. When you are camping in the summertime in the Southern states, temperatures can get quite high. That situation requires a powerful AC unit or two to make sure your RV or trailer’s interior does not get overly hot.

The difference between states like Florida, etc., and Texas and New Mexico, etc., will be the humidity levels. The humidity adds to the heat index so your AC unit needs to be powerful enough to handle that part of the summer heat.

If your 13,500 BTU unit struggles at 80 to 90 degrees F then yes, you should upgrade. A struggling AC unit is not providing you with relief from the heat. Also, check your budget.

The 15,000 BTU unit will use up more energy. Not much more by some people’s calculations but more none-the-less. Your budget will have to absorb that extra cost plus the cost of the upgrade.

Do some comparisons, check to see when and where you will be camping as well as the size of your RV. You may not need to upgrade because your RV is too small, you are not camping in hot weather or in locations that really require an AC unit to be on.

Some Final Words

Finding the right air conditioning unit for you will take a little research. You need to know the square footage of your RV, etc., and you need to know what the AC unit is rated for.

Also, watch the temperatures as the larger unit will be better in higher temperatures. You just have to make sure your budget can handle the increased costs associated with the bigger AC unit. Bigger is not always better in some circumstances.

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