Excessive Heat in Fifth Wheel

[jsteward1976]

This is a 4 part question. I have a Columbus Palamino 5th wheel and went camping this week in Texas. The temperature was only 91, but I was in full sun. I have 2 A/C units. A 15,000 btu Ducted Air Conditioning - Living Room and a 13,500 btu Ducted Air Conditioning - Bedroom, but my trailer got up to 88 degrees inside. I even had the fan on and window shades down.

1.) Is this normal being in full sun?
2.) If I tinted the windows would it help alleviate the heat coming in?
3.) I’ve seen the awnings that go over the slides. Are those worth it to help keep the heat out?
4.) The trailer is a mid bunk. The 2nd bedroom got up to 95 degrees. There was barely any air coming out of the air vent. I took the cover off and felt around but did not feel any obstruction. Is this normal for a 2nd bedroom to not get good airflow?

Thanks - Jeff

[Lexx]

Two ac units should handle 91°. Here's what we did to our trailer to help:
1) I added 20% ceramic window film to all our windows. I applied a double layer of film to the biggest window over the dinette in the kitchen. I did all of this myself using Concord ceramic automobile film from Windowfilm.com
2) On our Coleman ac units, there is a divider bar that separates the exhaust air from the return air. This divider bar was improperly positioned, allowing the cooled conditioned air to mix with the return air, greatly decreasing the efficiency of the ac unit. I moved the divider bar to the correct position and used hvac foil tape to secure it in place.
3) I pulled all the vent covers off and felt inside around the ducting. I found that some of the vents were improperly taped to the ducting system that runs around the trailer. This allowed cooled air to vent into the space between the duct and the ceiling material instead of into the room. So I used that same foil tape to make sure all the vents were sealed to the ducting with no obstructions.

Making these 3 changes has greatly improved the performance of our ac system. We were in Las Vegas where it was 100° plus, and we had no problem keeping the trailer in the mid-70° range.

Mid-bunk designs typically have but one small vent into that room with pitiful airflow. One person took apart the wall in which the vent was run only to find that there was only framing with no ducting at all. At the very least, I would investigate adding a duct booster fan. This will massively boost the flow of conditioned air into that mid-bunk room.

Oh and last thing. If your trailer door/s have any kind of window, get some ReflectX insulated foil to cover the window. That was another source of heat entry into our RV.

One more thing. If you don't have a foam insert for the roof vents, get one. They really help to block out the heat from entering through the roof vents.

jsteward1976 wrote:
This is a 4 part question. I have a Columbus Palamino 5th wheel and went camping this week in Texas. The temperature was only 91, but I was in full sun. I have 2 A/C units. A 15,000 btu Ducted Air Conditioning - Living Room and a 13,500 btu Ducted Air Conditioning - Bedroom, but my trailer got up to 88 degrees inside. I even had the fan on and window shades down.

1.) Is this normal being in full sun?
2.) If I tinted the windows would it help alleviate the heat coming in?
3.) I’ve seen the awnings that go over the slides. Are those worth it to help keep the heat out?
4.) The trailer is a mid bunk. The 2nd bedroom got up to 95 degrees. There was barely any air coming out of the air vent. I took the cover off and felt around but did not feel any obstruction. Is this normal for a 2nd bedroom to not get good airflow?

Thanks - Jeff

[Ron_Nielson]

One very useful tool to have to help evaluate and fix your HVAC problem is a simple USB borescope. This is a small device which has a camera and light on on end, a cable (you decide which length but 20 ft or so works fine)which plugs into a USB port of your laptop computer. There is generic USB camera software available for free if you don't get it with your borescope, and that should cost in the neighborhood of $20.

Now with the borescope, you can remove one of your vents and with your borescope attached/taped to a stiffener ( a length of 14 ga elec wire will do, or coat hanger, etc), probe the ducts of your trailer. You will likely find that there are holes or voids in the duct that let your cool air escape into the attic above the ceiling. How you patch the hole depends on where it is, access, etc. But I have done this on several trailers and found problems on each of them. After the first vent, go to the next vent, and the next, and the next until as much of your system has been scoped as possible and repaired.

You will be surprised at what a difference this makes.

[rhagfo]

ACZL wrote:
Do you by chance have slide toppers? They would help as well.

This makes a big difference in direct sunlight! place your hand on the slide cieling on a sunny day it will be very warm. We added slide toppers and it made a big difference. Also check the seal of the vents both at the A/C unit and the outlets. Use the foil duct tape.

[jsteward1976]

ford truck guy wrote:

jsteward1976 wrote:
This is a 4 part question. I have a Columbus Palamino 5th wheel and went camping this week in Texas. The temperature was only 91, but I was in full sun. I have 2 A/C units. A 15,000 btu Ducted Air Conditioning - Living Room and a 13,500 btu Ducted Air Conditioning - Bedroom, but my trailer got up to 88 degrees inside. I even had the fan on and window shades down.

1.) Is this normal being in full sun?
2.) If I tinted the windows would it help alleviate the heat coming in?
3.) I’ve seen the awnings that go over the slides. Are those worth it to help keep the heat out?
4.) The trailer is a mid bunk. The 2nd bedroom got up to 95 degrees. There was barely any air coming out of the air vent. I took the cover off and felt around but did not feel any obstruction. Is this normal for a 2nd bedroom to not get good airflow?

Thanks - Jeff

Is this a new trailer? Have you run the AC's in the past with no issues? A little more info could help us help you.

Yes, I bought it 8 months ago. I took it out last month, but the temps were only in the low 80’s. The mid bunk are was still warm and never cooled off.

[jsteward1976]

Bionic Man wrote:
What is the temperature of the air blowing out your AC vents?

I’m not sure. I didn’t have a temp gun with me. It did not feel that cold when I put my hand in front of it. I’m getting a temp gun to test it.

[amxpress]

Open the closet in your bedroom. Remove the shoe storage box mounted on the wall, it's secured by screws. Take a look inside the area behind the closet which is your front cap. You might see a few strips of fiberglass insulation. If you install additional installation inside the front cap, you can make a huge difference in the temperature inside the bedroom and trailer. If you keep the shades closed that's about the best you're going to get. We had a Columbus 320RS and when staying in Boulder City in August, it got over 100 degrees outside. Both units were kicking out max but couldn't get inside down below the low 80's. We did have a small fan we moved around inside.
When we arrived back home, I discovered the area behind the front cap barely had insulation!
After getting insulation from Lowes and spray adhesive, I increased the insulation and it really helped, especially in the bedroom at night.

[Allworth]

A long reply, but stay with me.


In 16 we left Yosemite in mid July to return to Florida by the southern route. Bartow, Tucson, Bisbee, Sonoma, etc. You get the idea. 35 foot fiver with 15K BTU ducted in the main area and 13K non-ducted in the bedroom. Double paine tinted windows. White roof and slide toppers on all three slides. The desert in July is not your friend.

In Tucson we went to Home Depot and got two rolls of Reflectix brand insulation foil and some blue painter's tape. This stuff is like aluminum foil bubble wrap and is also available, I think, at Camping World.

Cover the inside of every window you can reach. (That makes seeing out a little difficult, but heat comming in is the problem.) Cover skylights and vents also.

That made about a 15 degree difference in 105 degree heat. It is never going to get "cold" inside, but it was far better than 88.

Good luck.

[lenr]

On a prior trailer I found cool air leakage into the roof assembly at each duct outlet. I pulled each down and added foil tape to seal off.

[schlep1967]

You may also want to check the voltage coming into the fifthwheel. If everybody in the park is running two or three A/C units you may be getting low voltage and therefore poor performance from your units.

[TXiceman]

The trailer you have is poorly insulated to start with. If your two units are checking with the outlet air 18 to 20 degF colder than the inlet, the unit si a fine and you need to find shade.

DO NOT use an infrared temp gun to measure air temperature. They only measure the temperature from a solid surface.

Ken

[Cummins12V98]

Leave the fan in the ON position.

[BB_TX]

Our 5er does better than that. Also being in Texas we have been out in temps over 100 degrees and, for the most part, once the trailer is cooled the rear 15K A/C will keep it cool except for maybe the hottest part of the day.

I would guess either the A/C is not cooling properly or the trailer insulation is not adequate.

[ford_truck_guy]

jsteward1976 wrote:
This is a 4 part question. I have a Columbus Palamino 5th wheel and went camping this week in Texas. The temperature was only 91, but I was in full sun. I have 2 A/C units. A 15,000 btu Ducted Air Conditioning - Living Room and a 13,500 btu Ducted Air Conditioning - Bedroom, but my trailer got up to 88 degrees inside. I even had the fan on and window shades down.

1.) Is this normal being in full sun?
2.) If I tinted the windows would it help alleviate the heat coming in?
3.) I’ve seen the awnings that go over the slides. Are those worth it to help keep the heat out?
4.) The trailer is a mid bunk. The 2nd bedroom got up to 95 degrees. There was barely any air coming out of the air vent. I took the cover off and felt around but did not feel any obstruction. Is this normal for a 2nd bedroom to not get good airflow?

Thanks - Jeff

Is this a new trailer? Have you run the AC's in the past with no issues? A little more info could help us help you.

[pcm1959]

Doesn't sound right to me. Check the temperature of the a/c air going into the return vs the the temperature coming out. There should be at least a 20 degree difference. Then if the filters are not blocked and the condenser on the roof is not clogged then there is probably nothing wrong with the a/c units.
Window shades (white shades) will help keep out the heat. Window tinting is questionable because the dark color in tinted windows absorbs heat which transfer heat. I had an Outback fiver with single pane non-tinted windows and I tinted them with 3M reflective tint which helped with interior temps.
Walk around with an infrared temperature gun and check various areas of the rig to find out areas of excessive heat transfer. You may be surprised at the differences due to dark colors on the exterior, improper insulation installation, etc. Of course, not much of anything can be done about those factors.
Awnings and slide toppers may help but not black. My awning is black and the amount of heat that accumulates under it is unreal. White would be harder to keep clean but would reflect much more heat.
If you have a clear "storm door" it will allow a lot of heat inside so keep the solid door closed.
Finally, a 3rd a/c unit OR moving the bedroom air to the middle of the coach would help. The bedroom is much less volume to cool than the high ceilings of the main level.
Good luck.