Dometic vs. Coleman: Which RV Air Conditioner is Better?

dometic coleman ac lg

RV air conditioners are not cheap, and if you are thinking of replacing an old one, it is essential that you get it right. Let’s compare the 2 best-known brands of RV air conditioners and see which is better: Dometic vs. Coleman RV air conditioner.

Dometic air conditioners are better for smaller RVs that are up to 22 feet long, whereas Coleman air conditioners are better suited for RVs that are more than 23 feet long. Dometic air conditioners also have a lower profile than Coleman air conditioners.

So if you have a class A motorhome, you will want to get a Coleman AC.

There are some subtle differences between the performance levels of Dometic and Coleman products, so let’s have a look at the pros and cons of both brands.

Can you replace a Dometic with a Coleman RV AC?

It is possible to replace a Dometic with a Coleman RV AC. However, you will need to use a conversion kit. The conversion kit will allow you to convert the Dometic AC to a Coleman air conditioner.

The conversion kit you need to use is called the Coleman Mach Air-Vantage conversion kit. The great thing about the conversion kit is that it allows you to use your existing Dometic thermostat with the new Coleman AC.

Most RV air conditioners last between 3-5 years, depending on how much they are used and the weather conditions your RV is kept in. However, there are some RV AC units that are incredibly durable, and when properly maintained, they can last up to 10 years.

But how do you know when to replace your RV AC?

If you have had your air conditioner for more than 10 years, it’s time to replace it. Over time, your air conditioning system will become less and less efficient.

Also, older air conditioners were made to use R22 freon – which is a refrigerant that is terrible for the environment. Air conditioning systems that use R22 are being phased out over the next few years in some countries.

The second sign that you need to replace your RC air conditioner is if your expenses are increasing.

If your RV is using more electricity than usual, it is a sign that your AC is not working correctly. All other devices and appliances in your RV, from your refrigerator to your TV, all use a small amount of energy compared to your AC.

If your energy prices go up, it is a huge sign your AC is inefficient, and you may want to check it out or replace it.

The third thing to look out for is noise and dust. If your AC has leaks in the ductwork, then your air conditioner will push out dust. This is a big problem if you have children in the RV.

If you buy a new RV and use an old AC, and it is noisy in the new RV, you need to make sure the duct system in the AC system is large enough for the square footage of your RV.

The final sign you should replace your AC is when you notice inconsistent performance. If you have had the AC for less than 5 years, you might just want to get it checked out and repaired. If you have had the AC for 10 years or more, it’s time to upgrade.

When you replace an AC unit on your RV, you have to make sure your roof is sealed properly. 

Check out this recent article on my site where I tell you what the single best RV roof sealant is and how to do it quickly and easily yourself. You should be resealing your RV ceiling on an annual basis to keep your investment in tip-top condition.

Just click that link to read it on my site.

What is the highest-rated RV air conditioner?

The cooling capacity of an air conditioner is measured in BTU- British Thermal Units. If an AC has a high BTU, it means it can cool the air down quicker than an AC that has a low BTU.

When it comes to AC systems, a ton does not refer to the weight of anything. A ton refers to how much heat an AC unit can remove from your RV in one hour. Here is a list of tonnage to BTU:

  • 1 ton – 12,000 BTUs of air per hour
  • 2 tons – 24,000 BTUs of air per hour
  • 3 tons – 36,000 BTUs of air per hour
  • 4 tons – 48,000BTUs of air per hour

To help put things into perspective, 12000 BTU/hrs is the amount of heat required to melt one ton of ice in 24 hours. So, if your RV AC is rated at one ton, it can remove all that heat from your RV in an hour! That’s incredibly powerful, even for low-end AC systems.

Your RV will need one ton of air conditioning for every 300-600 square feet of space.

A higher tonnage air conditioner will cost more to run than a lower tonnage one, so if you are okay with waiting for 10-20 minutes for your RV to cool down, I recommend you get a lower tonnage air conditioner.

Nevertheless, the highest tonnage ACs from Coleman are the AC21 SEER Variable Capacity Air Conditioner and the AC19 19 SEER Two-Stage Air Conditioner. The AC21 is as low as 53 dB of noise, and the AC 19 is as low as 67 dB. The highest tonnage AC from Dometic is the Dometic Fresh Jet 3000.

Now when you’re connected to shore power, your AC can go indefinitely? But what about a generator? And will an RV’s AC even work on batteries?

If you want to find out how long you can run your RV air conditioner, check out this recent article on my site. I get into how much gas in a generator they go through, and whether they will even work at all if you just have battery power.

Just click that link to read it on my site.

Will a Dometic thermostat work with a Coleman AC?

You can use a Dometic thermostat with a Coleman AC If you have installed a Coleman Mach Air-Vantage conversion kit. This conversion kit will allow you to use your Dometic thermostat, control box, and ducted ceiling plenum with your new Coleman AC.

If you have an RV air conditioner, it is essential that you are connected to shore power powerful enough to handle it.

But while many campgrounds have 50-amp breakers, sometimes it’s only a 30-amp breaker, and a few ancient ones might only have a standard 15 or 20-amp breaker on a household outlet.

Will your AC work like that?

Check out this recent article on my site where I talk about whether you can use the common 20-amp breaker with an air conditioner. I get into how to know, what happens if you try it (will it blow the breaker or damage your AC) and a common work-around.

Just click that link to read it on my site.

Dometic RV air conditioners – pros and cons

The pros of Dometic RV air conditioners:

  • Dometic is one of the most well-established brands in the RV space
  • Dometic air conditioners are low-profile
  • They are a neutral color – white and look good on all RVs
  • They are relatively energy-efficient and are only as powerful as you need them to be

The cons of Dometic RV air conditioners:

  • They are not powerful enough for large, class A motorhomes more than 30 feet in length
  • They can be a little loud
  • Customers say that their customer service is not great

Coleman RV air conditioners – pros and cons

Pros of Coleman RV air conditioners:

  • Very powerful – suitable for RVs and residential use
  • Quiet

Cons of Coleman RV air conditioners:

  • Bulky
  • Expensive
  • Customers complain of poor customer service

When I searched online on YouTube, forums, and review sites, I found that both brands had customers complaining of poor customer service. If you want to get around this, try and buy your products from a retailer of the products, as opposed to directly from the brand itself. Maybe they will take better care of you.

Reviewing Dometic and Coleman Mach Air Conditioners


In conclusion, Dometic ACs are good for small RVs, and Coleman ACs are good for larger RVs over 7 meters in length. You need to have a power output of one ton per 300-600 square feet of living space.

The higher the power rating of your AC unit, the faster your RV will cool down; however, it will also take up much more power. You should replace your AC every 5-10 years.

You can use a Dometic thermostat with a Coleman AC if you use a Coleman Mach Air-Vantage conversion kit. If you replace your AC in your RV, make sure the ceiling is properly sealed after the work is done.

Photo by Mariakray:

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