Avoiding condensation in cold weather camping

Jay_and_Kat

In a couple weeks I'm going to be taking out our T@B 400 Boondock (2022 model year) and reading that people sometimes have issues with condensation forming inside the camper (especially on the ceiling,) I'm looking to check that what I'm going to do should help prevent / alleviate the issue. The campground I'm going to will probably be 40F or lower during the day and overnight below freezing.

First up, the roof vent will be kept open a bit, and at night especially, the fan on it's lowest speed pulling air out of the camper.

Second, the back window will be kept in the "2nd" lock position, so it's open just a hair, the front window will be in the same position.

Third, I bought a small USB fan suggested on the nuCamp forum, which I'll set up on the shelf under the TV at night, blowing up and towards the front of the camper to keep air circulating.  The fan is this one: https://www.amazon.com/dp/B09WK91TY2/ref=twister_B0BLBYS5D7

During the daytime hours, the windows will still be in the 2nd lock and when I cook, the fan will be running and blowing out the kitchen window (which I'll open a bit more.)

So, should I be good to go, or is there more I can do to alleviate the issue?

PNWtabber

I think venting is about all you can do, sounds like you are prepared.  I would pack an extra towel or two, I usually end up wiping condensation off the ceiling and windows.  I keep an electric dehumidifier in my trailer in winter when I am not camping (my trailer is stored at home and I have it on shore power). 

Jay_and_Kat

I'll keep the towels in mind (going to have a couple anyways)

Debating too, if I should open the bathroom vent and run the fan, at least after using the campground showers and putting the damp towel in there to dry.

dsfdogs

@Jay_and_Kat you may find with all the windows and vents open the Alde can't keep up with heating. The one time I've taken out my 400 this fall was cool and rainy. I had a single USB fan blowing in the back, vent open, and front window cracked. The only place I had condensation over night was the door window and I just wiped it off with a towel. During the day with the shade open, no issues. Have fun! It's all about experimenting. 

BurritoLover

For what it's worth... I recently picked up a 2018 T@B 400. I've only been out two freezing nights so far but haven't experienced any condensation. Once with heat and once without (whoops...empty propane!). No vents open, and no condensation... go figure.

bergger

You'll be fine.  I too have camped in freezing temps, high 20's and with the Alde running and the vent open or MaxxAir fan on low there has been no condensation on the ceiling or windows or walls.  The only place we have found a tiny bit of condensation, frozen, was on the single pane window in the door.  And that was minimal.  The key to keeping condensation down is air movement and keeping temps warm inside the camper.  We usually set the Alde to 55 overnight, sometimes have the MaxxAir fan on low and sometimes we just have it open and turned off.  

Homebodyatheart

@Jay_and_Kat when you do get condensation also check the inside far wall of all your cabinets. I’ve had condensation once and luckily checked them. Three had significant moisture on the back/outer wall which would have caused other problems if not caught. I can’t speak for a 400, but with my 320S all I need to do it lock the front window and one side window cracked open and the vent hatch almost closed but not latched (unless I’m in high winds, then latch.) I’ve been stuck in snow for three days last spring and had no problems! Play with it to see what works, don’t over think it. Enjoy your journey! 

PNWtabber

Good points being made about condensation being more of an issue in the 320 models than the 400 models.  The size difference could be a factor.  I know I have a lot more condensation in my 320 when my golden retriever is with me--the more breathing bodies the more it is an issue.  And a good reminder about condensation in cabinets.  When condensation is an issue, I open all of the cabinets to allow more air circulation, it helps a lot.

bergger

I do agree some with the size of the trailer having an impact but the key is to has some air movement and having the windows and walls warm.  When warm moist breath hits the cold walls it will condense.  Opening cabinets can help.  As another example I truck came with an AT Summit topper on my truck, down to 17 degrees so far have not had any condensation problems even with the tent material.  Again I keep it warm, with a truma heater, and have an insulated liner in the tent portion.  It has composite/carpeted walls, and very little exposed aluminum so minimal thermal bridging.  That is the weakness of the NuCamp products and most travel trailers, lots of thermal bridging due to aluminum studs and poor insulation.  However even with that type of construction I still have been able to keep the condensation to a very minimal in the trailer.  If NuCamp could just put some better insulation in between the interior paneling and the aluminum studs that would help a lot. 

PNWtabber

@bergger -- the first time I took my trailer out in winter, I was baffled at the condensation "stripes" on the ceiling.  I remember laying in bed staring at the ceiling trying to figure out what I was seeing. LOL.

AnOldUR

The hollow rectangular aluminum tubing is the problem. In another post I mentioned filling it with foam insulation at the factory. Is the welded wall and ceiling framing purchased from an outside vendor who could do this?

YanniLazarus

The (only)  "up-side" for the ceiling framing tube condensation lines showing is that you can locate them perfectly if you want to do something crazy like drill the roof to mount something...

Homebodyatheart

@PNWtabber here’s a pic I snagged of someone’s Tab in snow. It’s a great reference if I ever need it! 

PNWtabber

@Homebodyatheart -- wow, I've never seen the roof like that!  I'll have to check next time.

bergger

Wow is right!  No wonder they are hard to heat and cool. It is very clear now why the ceiling gets so so hot in the summer. I guess everyone just needs to understand the limitations of the trailers and accept them.  But I also wish they would just improve the roof a little bit which is not too difficult.  

BrianZ

The pattern in the photo above reminds me of the rear window electric defroster in our Sienna van.

MarkAl

The pic is interesting but is to be expected with a trailer design not specifically for winter use. The bracing, if made of aluminum will always conduct heat more quickly than the insulation. When more snow falls, it ALL gets covered. Cost and use case determine how extreme they design these. It would be interesting to see a model that was designed for winter use.

Also, an observation for the two of us at mid 20s (F) as low as we've camped. When we leave to explore I shut the windows down and lower the roof vent to just open. Unless we'll be gone all day also leave the heat up for in and out use. But at night and when we are in the trailer front and one side window is cracked to the 1st open with the vent open about 2 inches. If we cook the vent is higher and the fan is on. We don't have condensation issues. The problem is how often do you open the door and how many bodies are expiring moist air. The heater is relevant only because it raises the temp for the air to hold more moisture which then possibly condenses on the colder surfaces.

Simmons

We experienced condensation in our T@B 320-CSS at the end of September 2022 in Maine.  It had been a few cool rainy days, and cold nights.  So we were running the heater and had the windows cracked, could not crack the roof vent because of rain. In the CSS, there is an outside liftgate kitchen, and the bed is a small double, so we sleep cross wise with our feet to one window (on the door-side) of the T@b, and our heads to the other.  Both nights, the 2 blankets at our feet were quite wet over our toes where the blankets tucked in against the wall.  I believe it was the condensation on the door-side wall contacting with the warmer blankets. On the opposite wall, the head of the bed and pillows were okay.  We took the blankets to the laundromat to dry them and it happened again the next night.  We do run the heater at night, and the windows provided some cross air flow, but it was fairly still, not windy.  (The door-side of the T@B also has an awning that may cut off the air flow to the window).  Perhaps our fan would have helped?  I am going to pack an 18" tall x 48" sheet of closed cell insulation, that we can just tuck against the foot of the bed when we have cold wet weather.  We have had our T@B 5 years and this is the first trip this has happened.  .. Sure hope we find a solution.  

YanniLazarus

We always leave our factory original ceiling fan open about 1/2" in heavy winds, rain and snow - with the front (320) window in locked one- click open mode- when camping to provide circulation. Never any water leak at the roof fan. 

Slackers

@Simmons I believe it would have gone better for you if the roof vent could have been cracked open. Because we added a vent cover on our '19 CSS we can always crack the roof vent along with the front window. Sometimes we still have condensation that neatly forms on the aluminum framing of the roof and brads that tack the overhead trim in place. We have never suffered so much condensation that it couldn't be wiped off with a dish towel in the morning.

techietab

I did a cheap and dirty '4 season' mod on my 320S (involving a lot of heat pads and 12v wiring), and we've spent a ton of time over this winter camping in near-freezing or freezing weather. Never had any issue with humidity build up/condensation at all. Even when camping in near-freezing rain!

If we're camping, no matter the season - we at minimum either have the front window slightly open OR both side windows cracked the bare minimum with our Maxxair fan blowing out on one of its two lowest speeds. This keeps CO2 levels in the cabin acceptable (they can get CRAZY high if you don't have the fan on, especially with the window shades up or when there's little breeze), and seems to eliminate any humidity concerns. Both the Alde heater and the Air8 AC don't have any problem keeping up with the fan suction pulling in a constant small amount of outside air. We've even cooked pasta indoors during freezing weather without humidity buildup problems, though we opened up the front window and cranked up the fan while the stove was on.

Mickerly

Simmons, In our 2018 CS we have wetness on the driver side of the bed as well. I figured out the aluminum frame in the AC cabinet is welded to the outside frame and conducts heat. The edges of the cabinet collect moisture and it drips on our feet.

The air between the cabin and the kitchen exchanges through the under sink cabinet and the aft radiator. Don't forget to wipe down the kitchen at least once per day.... 

GregChris

Haven't to use it but, there is a dehumidifier setting on the air8, could you possibly run air8(dehumidify) and heat at the same time? We hardly ever camp below 40f and haven't a condensation issue yet. I always leave the front window in locked vent position no matter the time of day or season.

Mickerly

You have the newer air conditioner. We have no dehumidifier setting (2018 320CS). I think you can heat and dehumidify at the same time.

We recently spend a week with lows approximately 30 and highs around 38F. All the pressurized water lines are in heated parts of the trailer. All three holding tanks are outside, to include both sewer lines. We put gray water in a bin and dumped it each night. Disconnected the exterior water each night. The toilet is kind of heated by the cabin. We used a jug to hold water to flush with. During the day we were hooked into external water. One last thing, leave the lavatory door open at night. If you don't, the lavatory becomes a closet of very cold air. Not a pleasant surprise. I think you have a heater under the cassette.

The trailer in comfortable. Just keep in mind what is warm and what is outside.  ; )

I don't think this design is meant for much colder. I think the newer trailers have the dump valves remote at the bottom of the tank. The advantage is the ability to camp colder. The disadvantage is the extra volume in the waste tank from the line going to the trailer dump connection.