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Air conditioner not keeping up in 5th wheel

jeff__h
Explorer
Explorer
The 5th wheel is a 35QSIK with 4 slides.

Is it normal for the single air conditioner to struggle to cool the 5th wheel when the temp is only in the mid to upper 80s?

The air conditioner finally won, but it took hours to do so. The next day was much better because we left the air on all day so the RV was never allowed to heat up.

Doesn't bode well for later this summer with temps in the mid 90s.

If this is normal, what are my option to help keep the RV cool? I would rather not have to run out and buy a second AC unit if I can avoid it.
44 REPLIES 44

FlatBroke
Explorer II
Explorer II
We stay AZ in the winter but it can get into to 90's before we leave. Only 30 amp in the park. All the neighbors have a little longer rv's, none over 36', and vary from a Mobile Suite to a Monaco to a Sansabar to a Montana. All of them complain about their AC not keeping them cool. We only have one 15000 AC and you could hang meat in it when running, even shuts down when it reaches our selected temp. Not sure how it would do when it gets to a100, but we that are what the wheels are for.
On edit: bet 80% of the units are not blowing enough air. That is what the "tent in the vent" mod is for. increased air flow by about 50% in our prior 40' rv made a world of difference.

Hitch Hiker
"08" 29.5 FKTG LS

excelrvguy
Explorer
Explorer
A 15M A/C is designed to cool approximately 300 sq ft. With a very well insulated unit, they will do a little better than that but you can basically do the math and see how many sq ft your unit has with the rooms extended.

A triple slide 31' is usually around 350 sq ft and a 37' 3-slide unit will push 400 sq ft.

JamesBr
Explorer
Explorer
I could never expect 1 AC to keep my 3 slide 5er cool, but given how horribly inefficient RVs are up until the mid to upper 80's as long as I leave the AC on, usually only the main AC runs/cycles. Above that both ACs are running.
2006 Ford F350 6.0
2014 Primetime Sanibel 3600
Enough other vehicles to not bother listing.

Previous RV: 2001 Monaco Knight

ddschuman
Explorer
Explorer
Ours came with 2 AC's. Of course it was a dealer added option but was installed before we ever saw it. Come to think of it, I did not see one FW on that lot without 2 AC's. I assume maybe it was because they are a TX dealer and with the heat/humidity we get in TX, it is nearly a must to have 2 AC's on larger units. Regardless, I believe 2 AC's really help. We have camped before where we only had 30amp and could only run one AC at a time. Even though the BR is ducted to the downstairs AC, it never got very cool during the day. At night, we would turn off the downstairs and turn on the BR. Also, we have found that when you do have 50amp service and running both units, if you close the vents to the BR, it helps keeps the downstairs cooler and the BR AC is more than sufficient enough to keep the upstairs cool by itself.
Escaping the real world in our "home away from home"
2016 Cedar Creek 36CKTS
2016 Chevrolet 3500 High Country Duramax Dually

taken
Explorer
Explorer
We added a second unit this spring. It's inexpensive and easy to do yourself. (Under $600 delivered for a 13.5.) Our's came with a single 15k that was fine most times but not enough every time. When we know it's going to be hot we also run our generator while traveling to the CG and leave the AC on. Then it's nice and cool when we arrive. This is another great reason to have a generator.
Regards, Rodney
TV - 2017 F350 SRW CC SB 4X4 6.7
TH - 2015 FR XLR 395AMP

jalichty
Explorer
Explorer
Two years ago we went to Zion Canyon and it was around 95 degrees. We didn't turn the AC on when we left for the day and paid for it later as the trailer had gotten very hot and the AC didn't want to turn off and ran all the time. This year we stopped in Palm Desert and the temperature was 108 while we were away, but we had set the AC at 80 when we left and the FW was comfortable when we returned that afternoon. Then turned it down to 75 to cool off for sleeping and the AC cooled the FW off very nicely and it was comfortable sleeping. However, our FW is a lot small than yours, only 30' overall. With a FW as big as yours, two ACs might be the only way to go.
John A. Lichty

GPG52_
Explorer II
Explorer II
When we shopped around for our new 5th wheel we looked at
1- R insulation factor, ceiling, walls and floor
2- window configuration

Then we added
I) second AC in the bedroom
II) toppers over the slide, to both keep the slides clean and 2nd hopefully help keep them a little cooler

We plan on much southern RV'ing... so next step if needed will be the window awnigns.
GPG
GPG 🙂
2014 Ford F250, 6.2L, 4.30 Ratio, 6 speed
2014 Cougar (by Keystone) 327 RES

pennysmom09
Explorer
Explorer
We had the same problem this past winter in Florida. The few days we had in the upper 80's, the AC struggled. Our new unit, on order, has 2...a 15k btu and a 13k btu in the bedroom. We could not travel in hot weather with just the one.
Nancy and Doug
2015 KZ Durango 325RL FW

time2roll
Nomad
Nomad
Could have some install issues. Get up inside and look for ducting issues where visible. Also check the plenum is separated properly between the in and the out. Otherwise let it run.

nylyon
Explorer
Explorer
I added a second A/C to mine as well. The single 13.5K worked okay, but the second really cools the unit down quickly. Both of mine are fully ducted which gives added bonus. Say you're in the living room, turn on the bedroom A/C to keep the camper cool and it's almost silent in the living room. Visa versa for the bedroom.

The initial cost is a little high, but if your 5th is prepped, you can likely install it your self. Mine was getting warranty work done on it, and they cut me a break on the installation so I had it done! Don't be discouraged, those of us with 2 will almost always say it's money well spent and you will too!
Karl, Liz, 3-kids and Pepper the puppy

2011 Jayco Eagle Super Lite 30.5 BHLT
2003 F-250 FX4 6.0 Powerstroke

mdamerell
Explorer
Explorer
Palomino Sabre 35QSIK, which I'm guessing you have, is a 40' 5er (39'4" according to what I found). That's a lot of space to cool off with one AC unit. Everyone has a different comfort level. Some are happy at 80 degrees. Due to health issues we found we needed the 2nd AC unit to maintain the doctor recommend 70 degrees.

Dealers tend to order RV's prepped for 2nd AC to keep the advertised price down. We added a heat pump in the master bedroom instead of a straight AC unit for $1000 installed. I thing it was like $700 for just a 2nd AC unit installed. Ours is a non-ducted unit. It's not hard to install one but getting the unit on the roof can be tricky.
2012 Sundance 3100RB w/Reese Goose Box
2004 Ford F350 6.0 L PSD, CC, DRW, long bed, B&W drop ball hitch, Firestone Ride-rite air bags.

tvman44
Explorer
Explorer
Sounds par for the course, especially around here.
Papa Bob
1* 2008 Brookside by Sunnybrook 32'
1* 2002 F250 Super Duty 7.3L PSD
Husky 16K hitch, Tekonsha P3,
Firestone Ride Rite Air Springs, Trailair Equa-Flex, Champion C46540
"A bad day camping is better than a good day at work!"

laknox
Nomad
Nomad
jeff h wrote:
HappyKayakers wrote:
I have a single AC with 4 slide 5er. Have you tried the Quick Cool feature on your AC? On mine, it's a vent that opens directly below the AC unit and dumps lots of cool air into the RV very quickly, more than you can get through the ductwork.


Yes we did. It is loud as heck but does a good job in the main room. Unfortunately , at the expense of the bedroom.


Sounds like a 2nd A/C is what it might take. Not news I really wanted but it is what it is.

Some other good tips of things to check next time I head out. Thanks folks. Keep the advice coming.


A couple of small fans, as others have said, are an excellent short-term (and inexpensive) solution.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

jeff__h
Explorer
Explorer
HappyKayakers wrote:
I have a single AC with 4 slide 5er. Have you tried the Quick Cool feature on your AC? On mine, it's a vent that opens directly below the AC unit and dumps lots of cool air into the RV very quickly, more than you can get through the ductwork.


Yes we did. It is loud as heck but does a good job in the main room. Unfortunately , at the expense of the bedroom.


Sounds like a 2nd A/C is what it might take. Not news I really wanted but it is what it is.

Some other good tips of things to check next time I head out. Thanks folks. Keep the advice coming.

TXiceman
Explorer II
Explorer II
In the south, anything over 30' needs two A/C units, unless you can keep the trailer in total shade from a bout noon until dusk.

You should pull down the A/C trim to make sure it is all properly sealed and no holes where the wires go back into the ceiling. The manufacturers do a poor job of installing the units. Also make sure there are no leaks between the inlet and the outlet side of the unit.

You can see if the unit is doing all it can do by running the unit on high fan for 10 minutes or more and then take readings as close to the unit as possible. Use a thermometer and not an infrared temperature gun as it will not measure air temp, but it will measure the temperature of the plastic. The leaving air should be 18 to 20 degF lower than the inlet air. More or less means you probably have a problem.


Say what?------------------------------------------------------
4.Turn the thermostat to just above the lowest setting. Ours works better at just above the lowest setting for some reason.

This baffles me as that is not how a unit works. It produces as much cooling as possible right up until the thermostat shuts down the unit. When the thermostat warms about 1 degree above set point it comes on again.

Ken
Amateur Radio Operator.
2023 Cougar 22MLS, toted with a 2022, F150, 3.5L EcoBoost, Crewcab, Max Tow, FORMER Full Time RVer. Travel with a standard schnauzer and a Timneh African Gray parrot