Dear Dave,
What is a “good” alternative to an RV rooftop air conditioner? The more I look at it, the more confusing it gets. I should have added a second A/C when I ordered my current rig. I am open to any options! Thank you. —Randy, 2022 Flagstaff 8529RLS
Dear Randy,
I don’t know if there is a “good” alternative due to the beating any type of air conditioner on an RV gets while rolling down the road or sitting idle in 100+ degree and -0 degree temperatures.
The traditional RV roof air conditioner works very similar to a residential style by drawing interior air up through the return air vent by the fan/motor. It is pulled over the evaporator coils that have a series of zigzag copper tubing where the refrigerant flashes and pulls heat and moisture out of the air. We have had numerous comments in a recent article about why they can’t be recharged like automotive or residential models can, so we won’t go into that.
Mini split units
I have found several posts recently about mini split units that have been installed by owners, but I don’t have any experience with that myself. From what I have researched, the mini split works the same as a residential or conventional RV air conditioner. It has become popular in residential applications for rooms that need a little boost in cooling. There are many different brands such as LG, Pioneer, and others, and it seems the average size is 9,000 BTU and can go up to 12,000 BTU. You can find them on Amazon here.
The evaporator goes inside and compresses the refrigerant just like a conventional RV roof air conditioner, while the condenser goes outside the rig and is the larger box with the fan. Most of the applications that I found were on trailers, and the condenser was placed on the trailer tongue. I think due to the weight and road vibration it would not hold up so well on a backwall outside, which would need to be the application for a motorhome. There are also models available up to 24,000 BTU; however, they do require 208/230V. The smaller unit weighs an average of 20–40 lbs., while the larger unit is 65–90 lbs.
The downside of these units that I have found is the ductless system has a limited cooling space and a larger rig would most likely need two. However, since you already have one roof air now, it might be an option. And the reviews look good but most, I believe, are not from RV owners.
What about portables
I have tried a few portable units in the past, including a tabletop model, and most are worthless. They simply provide a water mist with a fan and that adds humidity to the room. I see them “hawked” all the time at RV shows, but the same vendor or manufacturer is never back at the show the next year.
Let’s see what our readers have found with the mini splits and portables.
You might also enjoy this from Dave
How can my RV’s roof air conditioner run more efficiently?
Dear Dave,
I’d like to improve the efficiency of our roof air conditioner. The factory shrouds are black. I’d like to paint them white. Second, I’d like to insulate the pipe from the compressor to the evaporator. Thanks. —Joe, 2019 Coachmen Pursuit
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
Read more from Dave here.
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I am a mechanical engineer and formerly ran a custom A/C business that was an early adopter of variable capacity A/C for server room units in 2013. I built and live nearly full time in a custom ‘adventure truck’ (Maximus) with a 9k LG mini-split. I have produced a fairly extensive series of videos comparing types of A/C units for RV use at YouTube.Com/WorkingOnExploring. I also list much of my comparative data on my website at WorkingOnExploring.com/TechDocs.
The good news is that the technological state of the art and equipment exists (variable capacity mini-splits). The bad news is that no one has put it into a RV rooftop package, nor are they likely to any time soon.
The reason is economic incentive. If the majority of RV users are operating on grid power in RV parks which is not billed to them at a metered rate, there is NO INCENTIVE to seek more efficient/better performing equipment.
The residential market is driven by government regulation requiring improved efficiency and that is where the $$ are, providing the industry with incentive. Only when there is a better, direct coupling to cost and performance will there be an RV industry wide demand for A/C improvement.
The most likely near term replacements are ‘window’ of ‘through wall’ units that are starting to be built with some of the variable capacity in min-splits and getting somewhat quieter. RV users should want to have a split system, not a roof mounted one. The roof is lightly built (I am also a former Safari Motor Coaches Plant Engineer) making it an effective ‘sound diaphragm’ to conduct A/C vibration.
The direction of the serious RV manufacturers who are pursuing A/C for other than RV park operation, are heading to 48V electrical systems for which equipment and mini-split units are available (HotSpotEnergy.com). The variable capacity and heat pump capability of refrigerant systems cannot be beat if well done. Unfortunately, most RV roof top units are the worst examples of the refrigeration art.
One of the reasons I opted for a 16’ Casita TT was the AC was a through-the-wall type Window Unit. Located in the front closet. So simple ,quiet (you can barely hear it running from outside) and efficient. Both the 16s and 13s had these but alas neither of these trailers are made anymore, only the 17’ with the Haybale type Roof AC.
I’ve seen a couple of entry level small trailers with these Window type ACs incorporated into one of the closets but not very many. Seems like a glaringly simple solution to the small trailer AC problem instead of that ugly inefficient Haybale that seems to be the Industry’s solution.
My first RV began life as an army shop van, an insulated box sitting on the frame of a 2.5 ton truck frame, essentially a 6 wheel drive vehicle. I installed 2 beds, cabinets, a fridge, sink, shower/toilet, fold-down table and benches, cabinets, 2 water heaters, 125 gallon stainless steel water tank, and waste water collection tanks. I fabricated space for a 30 Amp generator and fuel storage and installed a 9000 btu heat pump I found on line. There were several options for mounting the exterior unit and only one for the interior one. My small generator easily funs it as it draws 7 amps and 117 vac. The efficiency is amazing as it deals easily with Texas summers keeping the interior cool. But, it also manages to warm the interior during sub-freezing temperatures we have experienced. A small 8″ box heater will also heat the interior. I have 2 banks of gel cell batteries that are wired for 24 vdc. The batteries are chargeable from shore, the generator, the truck’s engine, or solar panels on the roof allowing flexibility. The 6 wheel drive can pull the rig anywhere including a 45 degree incline and can do so pulling my 1951 jeep or a 1.5 ton military trailer filled with supplies. I am not the first guy with the idea of such projects, Gen. George Patton had the first 2 built for him during WWII. Every 2 years, a convoy of similar military vehicles can be seen driving a stretch of historic highway in a convoy. We will drive the length of the Jefferson Highway in October 2024, Winnipeg to New Orleans. Check for the MVPA on social media and come see how some old guys with common sense figured out hot to easily heat and cool RVs and how they work. My 2022 Jayco 5th wheel looks pretty behind my big Ford and has more room and features, but its cooling system is a loud energy hog and it sure will not boondocks in the real back country like my deuce and a half.
What we need is a mini split unit that will bolt in place of the rooftop unit. That way it is easy to install and uses existing duct work.
I’ve found three portable (under 60 lbs), compressor-type (not swamp cooler), dual hose (doesn’t pull in dirty outside air) air conditioners suitable for class B vans or other small spaces.
ZeroBreeze Mark 2
EENOUR pa600
Ecoflow Wave 2
After watching youtube reviews and waiting for deals, we just bought the Ecoflow Wave 2 with battery for $1700 on Amazon.
My son put a minisplit on his homebuilt F550 cab-over… he has enough solar and lithium battery capacity that he can run it all day in the desert heat, and its very quiet. I’m not sure how big the cabover is, maybe 24′ overall length? The camper is all alumimum, mig welded 2″ square aircraft style tube frame with 6061 sheet metal skin, and plenty of insulation.
I live in the coastal southwest and while a renter for many years I had to resort to using temporary window AC units as most rental units did not have AC built in. Most of the year didn’t need them, but sometimes you do. I believe I used to pay around $125 for a small 5,000-8,000 btu model which I just hoisted into a small outside temporary 1×4 shelf. This worked very well and efficiently. Now that I’m an owner of a ’09 Winnebago View which seems to have a terrible time in over 90° keeping us cool (brand new 13,500btu). I often think maybe a little add on unit would help a lot. Doesn’t have to be permanent install.They’re quit small like a counter top microwave although heavy. Not sure of the amp draw tho?
Thank you, Dave!
I added a 110 volt 9000 btu inverter mini split with A/C and heat to my campervan for about $700 and I did the installation myself. It’s quiet and will cool the interior down in less than five minutes. It uses about 650 watts for about five minutes at startup and then about 250 watts to maintain. I have 650 watts of rooftop solar and 400 ah of lithium batteries so I can run the mini split and still be charging the batteries during the day. One of the best additions I ever made. I honestly don’t know why the industry hasn’t moved toward the mini-split. We love it so much I added a 220 volt 12k btu unit to my house bedroom and now sleep cool in the summer and warm in the winter and it’s whisper quiet.
I have a 30 foot Class A that has one roof air and a 30amp service – The one roof air did not cool the motorhome sufficiently even with a new Coleman Mach 15. I added a portable AC unit that vents like a dryer in the bedroom and vented it out a small window, you have to look very close to see any sign of the vent from the outside. Running both units I am able to keep the motor home very cool in 100 degree weather. The best part is i am able to run both units using the 30amp service or the 4kw generator.
A couple decades back, roof A/C units were less common. I’ve seen a number of travel trailers equipped with a form of through the wall A/C units. Typically the unit protruded through the wall just far enough so the condensation didn’t run down the side of the trailer and the rest of the unit was inside in some form of cabinetry. I’ve noticed the current models of window A/C units are increasingly smaller for the number of BTUs they handle. If your RV can give up the wall space, I’m pretty sure they would do a better job than many of the current roof mounted units.
I’ve seen several mini split units installed in home built utility trailers conversions to campers and no one complains about any of them. We lived in FL for a year in a park model style RV with a FL Room addition. The standard 21,000 BTU heat pump did a halfway job of cooling the main part of the unit but couldn’t keep the FL room anywhere close to cool. We installed a mini split unit with 2 inside units(one in each section of the unit) and it immediately cooled both sides, plus this last winter we got down below freezing for a couple days we stayed toasty warm. It convinced me on mini split units, if I had a rooftop unit failed or I was buy a new RV I’d use one of these instead.
The primary difference between a mini-split and a conventional unit is the compressor and the lack of ducts. The mini-split uses an inverter and the compressor is DC and infinitely variable. The smallest units are available in 120V. The maximum size appears to be ~ 12k BTU and would require a 15 amp minimum branch circuit. The current crop of RV units are pretty rudimentary and are not particularly efficient. There are add on electronic controls that help alleviate some of the issues.
All about rv’s has a good vid about topic.
https://youtu.be/1g2EKArdokM
I put a Mr.Cool 12k mini split from Costco on my 20’ TT two-plus years ago. As Dave said, I put the condenser on the A-frame and mounted the air handler on the cabinets above the bed at the front of the trailer (after adding more bracing). My trailer is one room so it works great for heat and A/C and is barely noticeable for noise.
I just saw that Mr.Cool and others have the option of a ‘ceiling cassette’ for the inside unit which might be an option. My trailer did not have a vent fan in the cabin, only the BR, from the factory so the roof A/C hole now has a vent fan.
I’m not an HVAC person so the install took a while. Getting it serviced is a challenge. RV techs are like, “what’s a mini split?” HVAC techs say, “If it moves we won’t touch it.” It’s fun to talk about the mini split but at some point there needs to be a 12v RV HVAC unit that is not a modified home unit. IMHO
Oops! Hole, not whole. Please forgive me it’s early.
Dave,
You missed the fact that mini splits are heat pump/ AC’s. We have a factory installed rear cargo carrier so it provided more than sufficient capacity to carry the weight of the outside unit. I ran the tubing and electrical down under in the underfloor space, up into the rear corner, and into the rear cabinet. On 90+ degree days it will cool the inside to 65 degrees. On 22 degree nights it warms us to 72 degrees. Added bonuses: 1) 2X the Seer rating compared to the roof unit. 2) It’s whisper quiet, compared to the jet-roar of the roof unit. 3) It takes the weight off the roof and lowers the center of gravity. 4) It lowers the 5th wheel height by 10 inches. 5) We use very little propane in the winter (we don’t boondock but because it uses 1/2 the wattage of the roof unit, it would be a better option for those who want to combine solar with AC). 6) No more jet roar from that inefficient RV furnace.
So why can’t the RV industry change to this new technology. It’s rechargable. It’s cheaper. It doesn’t require ducting below the floor and above the ceiling? Two units could heat and cool an RV for the same electric required to run one roof AC.
It’s definitely my first choice if our roaring roof unit fails. Check out Youtube and see it is a popular choice. I would even consider cutting a whole in a sidewall and bracing it for a cheap window unit that slides in when the RV is moving. I wouldn’t hold my breath for the industry to such bold step into the 21st century.
Oops! Hole, not whole. Please forgive me it’s early.