MuskokaMudder
World Explorer
What methods are used for dealing with moisture in these rigs? How do you deal with Cold weather travel?
Dehumidifier
Run AC
Live with it?
Thanks
Dehumidifier
Run AC
Live with it?
Thanks
Dealing with moisture
- Thread starter MuskokaMudder
- Start date
fluffyprinceton
Adventurer
Insulation
Heat
Ventilation
The insulation and how it's configured - deals with wall/ceiling/window condensation. Cold paths through window trim and on insulated windows themselves will be an annoying source of condensed water in the camper envelope even in well insulated campers. Also any hatches in the ceiling will drip from condensation so place them accordingly...The amount of nuisance condensed water will depend on the your heat & ventilation.
The more ventilation you have the more heat you'll need. Ventilation is pretty straightforward - open a window - but the type of heating makes a difference. An inexpensive catalytic heater is the worst for condensation - they actually add moisture to air. An outside vented forced air heater is better & a diesel fired hydronic heated with water/air heat exchangers and a radiant floor circuit is probably optimal for cold weather livability.
The overall camper design comes into play as a poorly insulated camper with limited ventilation to the closed storage spaces will become a moldy mess if "put up wet" after a winter camping trip.
In a typical production camper one way to go is heat as little as possible for sleeping (I hope you are happy in a sleeping bag...) and use full heat just for eating & a bit of comfortable hangout time. The idea is to make sure the camper & bedding don't get progressively wetter...Because the condensation in a typical production camper can be astonishing under the worst conditions. My favorite cold weather mod is a blower with a hose from your truck cab to the camper so your engines waste heat goes to heating & drying your camper - with the huge added benefit of supplying enough added air pressure to the camper envelope to keep all that dust from sucking into the camper. Moe
Heat
Ventilation
The insulation and how it's configured - deals with wall/ceiling/window condensation. Cold paths through window trim and on insulated windows themselves will be an annoying source of condensed water in the camper envelope even in well insulated campers. Also any hatches in the ceiling will drip from condensation so place them accordingly...The amount of nuisance condensed water will depend on the your heat & ventilation.
The more ventilation you have the more heat you'll need. Ventilation is pretty straightforward - open a window - but the type of heating makes a difference. An inexpensive catalytic heater is the worst for condensation - they actually add moisture to air. An outside vented forced air heater is better & a diesel fired hydronic heated with water/air heat exchangers and a radiant floor circuit is probably optimal for cold weather livability.
The overall camper design comes into play as a poorly insulated camper with limited ventilation to the closed storage spaces will become a moldy mess if "put up wet" after a winter camping trip.
In a typical production camper one way to go is heat as little as possible for sleeping (I hope you are happy in a sleeping bag...) and use full heat just for eating & a bit of comfortable hangout time. The idea is to make sure the camper & bedding don't get progressively wetter...Because the condensation in a typical production camper can be astonishing under the worst conditions. My favorite cold weather mod is a blower with a hose from your truck cab to the camper so your engines waste heat goes to heating & drying your camper - with the huge added benefit of supplying enough added air pressure to the camper envelope to keep all that dust from sucking into the camper. Moe
MuskokaMudder
World Explorer
Thanks, these are good suggestions.
If you have a larger platform, like a mog 8x14, does adding a dehumidifier make any sense? Has anyone tried this?
In my truck I often run the AC at full temperature in winter to eliminate moisture in the cab, is this feasible in a EV setup?
Thanks
Andre
fluffyprinceton
Adventurer
Andre - Without knowing what kind of camper you have, your budget & your desired comfort level it's pointless to do more than deal with generalities...Judging by your location you have a serious cold weather situation which suggests a serious solution/mitigation. Doesn't have to be expensive but all the solutions/migrations are rig specific...and no rig is mentioned...
"anyone weigh in with additional methods to eliminate thermal bridging?" - post build? No, at least I can't think of any. In the design phase there are many ways to eliminate/mitigate thermal bridging.
and thoughts on vapor barriers?" - A camper isn't a house & it's a rare one that isn't far more "vapor barricaded" than a house. The issue is human produced wet vapor and when it condenses on a cold interior wall, window or metallic window/door frame. A campers small interior volume combined with the inconveniently large breathing mammals within cry out for breathable exterior walls - not vapor barriers... I mention breathable exterior walls only as a...hypothetical solution...at least until an insulated/structural Goretex is invented. Moe
"anyone weigh in with additional methods to eliminate thermal bridging?" - post build? No, at least I can't think of any. In the design phase there are many ways to eliminate/mitigate thermal bridging.
and thoughts on vapor barriers?" - A camper isn't a house & it's a rare one that isn't far more "vapor barricaded" than a house. The issue is human produced wet vapor and when it condenses on a cold interior wall, window or metallic window/door frame. A campers small interior volume combined with the inconveniently large breathing mammals within cry out for breathable exterior walls - not vapor barriers... I mention breathable exterior walls only as a...hypothetical solution...at least until an insulated/structural Goretex is invented. Moe
MuskokaMudder
World Explorer
Thanks Moe
I am in the planning stages of buying/building of a unimog something. Cold weather is part of our planned travel route as is desert. I know this is a consideration so I wanted to see what people do to manage moisture.
Iain_U1250
Explorer
I looked a insulation, condensation etc when building my truck, like everyone has said, main cause of moisture is people ( unless you are boiling lots of water for tea constantly. The only way to reduce condensation is through ventilation. If it is very cold outside, then you need to heat up the air coming in and let it out somewhere. All the insulation in the world won't help is you have created your own sauna. .
As an example, I used to run a concrete lab, inside it was around 90-100% humidity, 26 degrees C. If someone opened the big outside door in winter ( 5-10 degrees C), cold air would form "clouds" and it would rain inside our lab
I have a number of cold bridges which I could not avoid, the main one being the legs of the rear seats, which needed to be steel and part of the overall frame in order to get the certification for the seat belts for rear passengers here in Australia. It will be covered with a wood trim, but I expect it will be the main source of condensation but we will just have to live with it. In cold weather we will have block of the crawl through, otherwise the cab windows and windscree will be constantly dripping, nothing we can do to insulate them
We have a 9kW diesel heater, and out camper internal dimensions are 1.9m H x 2.0m W x 3.3m L. so 12m3, with about 20% taken up by furniture, so lets say around 10m3 of air space. Our 4 fans are capable of putting 200m3 per hour through the heat exchangers, so we could be changing the air around 20 times in an hour if the heaters are capable of keeping up with that volume, 9kW is a fair bit of heat. I used this graph http://www.chromalox.com/catalog/resources/technical-information/Heat-Loss-Calculations-and-Heater-Selection-Air-and-Gas.pdf to work out that we needed 5kW of heat to heat up the 100cfm approximately from -20 C to + 25C .
Probably not the right way to do it, but should be close enough. It looks like if the camper is warm, from driving around, we should be able to keep it warm, and fairly dry as well. Like all things time will tell if I got it right.
As an example, I used to run a concrete lab, inside it was around 90-100% humidity, 26 degrees C. If someone opened the big outside door in winter ( 5-10 degrees C), cold air would form "clouds" and it would rain inside our lab
I have a number of cold bridges which I could not avoid, the main one being the legs of the rear seats, which needed to be steel and part of the overall frame in order to get the certification for the seat belts for rear passengers here in Australia. It will be covered with a wood trim, but I expect it will be the main source of condensation but we will just have to live with it. In cold weather we will have block of the crawl through, otherwise the cab windows and windscree will be constantly dripping, nothing we can do to insulate them
We have a 9kW diesel heater, and out camper internal dimensions are 1.9m H x 2.0m W x 3.3m L. so 12m3, with about 20% taken up by furniture, so lets say around 10m3 of air space. Our 4 fans are capable of putting 200m3 per hour through the heat exchangers, so we could be changing the air around 20 times in an hour if the heaters are capable of keeping up with that volume, 9kW is a fair bit of heat. I used this graph http://www.chromalox.com/catalog/resources/technical-information/Heat-Loss-Calculations-and-Heater-Selection-Air-and-Gas.pdf to work out that we needed 5kW of heat to heat up the 100cfm approximately from -20 C to + 25C .
Probably not the right way to do it, but should be close enough. It looks like if the camper is warm, from driving around, we should be able to keep it warm, and fairly dry as well. Like all things time will tell if I got it right.
southpier
Expedition Leader
this seems a bit confusing. my understanding is that a vapor barrier controls where the moisture is allowed. wouldn't a vapor barrier applied to the heated side of the insulation contain moisture so it could be actively disposed? (in theory - fan/ open window)
if moisture is allowed into the wall cavity, what happens when it reaches the inside surface of the vehicle's outer skin? and on a hot day parked in the sun, is this contained moisture driven back into the cavity only to condensate on the wrong side of the vapor barrier? molding, and eventually rusting out the rocker panels (in the case of a van)?
MuskokaMudder
World Explorer
Very helpful, IanI looked a insulation, condensation etc when building my truck, like everyone has said, main cause of moisture is people ( unless you are boiling lots of water for tea constantly. The only way to reduce condensation is through ventilation. If it is very cold outside, then you need to heat up the air coming in and let it out somewhere. All the insulation in the world won't help is you have created your own sauna. .
As an example, I used to run a concrete lab, inside it was around 90-100% humidity, 26 degrees C. If someone opened the big outside door in winter ( 5-10 degrees C), cold air would form "clouds" and it would rain inside our lab
I have a number of cold bridges which I could not avoid, the main one being the legs of the rear seats, which needed to be steel and part of the overall frame in order to get the certification for the seat belts for rear passengers here in Australia. It will be covered with a wood trim, but I expect it will be the main source of condensation but we will just have to live with it. In cold weather we will have block of the crawl through, otherwise the cab windows and windscree will be constantly dripping, nothing we can do to insulate them
We have a 9kW diesel heater, and out camper internal dimensions are 1.9m H x 2.0m W x 3.3m L. so 12m3, with about 20% taken up by furniture, so lets say around 10m3 of air space. Our 4 fans are capable of putting 200m3 per hour through the heat exchangers, so we could be changing the air around 20 times in an hour if the heaters are capable of keeping up with that volume, 9kW is a fair bit of heat. I used this graph http://www.chromalox.com/catalog/resources/technical-information/Heat-Loss-Calculations-and-Heater-Selection-Air-and-Gas.pdf to work out that we needed 5kW of heat to heat up the 100cfm approximately from -20 C to + 25C .
Probably not the right way to do it, but should be close enough. It looks like if the camper is warm, from driving around, we should be able to keep it warm, and fairly dry as well. Like all things time will tell if I got it right.
pugslyyy
Expedition Vehicle Engineer Guy
NeverEnough
Adventurer
I think this is the most important concept in a small spaces, like a camper. Air always seeks equalization (pressure, temp, humidity), so give it someplace to go.
Of course, we're reluctant to let all that precious warmth out after working so hard to create it and keep it in. That's one of the main reasons I like radiant heat. If your living space is designed to heat THINGS (especially the heavy stuff) in stead of AIR, then you don't worry so much about letting some hot air escape, along with all the moisture it carries. I used the same principles in my camper that I learned when I built my last house- overkill on insulation, radiant barriers, reflective insulation, and ventilation. An extreme example is my garage. It's huge, almost 1600 square feet, concrete floors (w hydronic tubing), walls, and roof (patio above), and very well insulated (even the doors). We have plenty of sub-zero temps at our elevation, and it always amazes me how quickly the space "feels" warm again after closing one of the doors if it's been open for a few minutes. All that heated concrete warms up the air almost instantly.
One of the challenges in a mobile situation is that you've got limited mass in order to keep things light, so reflective insulation plays an even bigger role, to bounce the radiant energy back into the living space. I've had zero condensation issues in my rig, even with 8 bodies in there all night in subzero outside temps.
fluffyprinceton
Adventurer
Good point - especially in stick built campers where the inner skin isn't bonded to a core material or is of a material that passes vapor easily. A vapor barrier is necessary to prevent inter wall condensation - thanks for bringing that up. It won't help with the nuisance of condensation getting into your bedding but it's essential - as a general rule any structural composite panel will likely be a vapor barrier due to the way the core is bonded to the skins but it's worth thinking about as I'm sure there are exceptions. In the marine applications I'm most familiar with the moisture gets into the core through unsealed penetrations - but that's another problem.
If you are serious about cold weather comfort floor radiant is best. You can blow hot air around all you want but if your 2-3 inch well insulated floor has sub-zero weather on the other side it's just not going to ever be warm. Nothing wrong with down booties but having your main source of heat rising evenly from your floor, well - it's just very nice...A hydronic system run off your diesel supply with loops to your engine, domestic h2o heat & a mix of radiant & water/air exchangers solves a lot of cold weather issues elegantly but it's a complex & expensive bugger to design & install. For me the ability to run house heat on battery power & diesel alone for a couple of days was essential. My experience with floor hydronic radiant in campers is that they are (or should be...) a different animal than the typical building type where the tubes or wires are imbedded in a concrete mass which takes time to heat up. I've only used copper tubing with the floor material basically in contact with the copper - it heats up fast - well 15 to 20 minutes anyway from a cold start. As long as your flooring & glue systems are up to the temps it's a good system although I'd like a budget that allows a copper sheet to go over the tubing with the flooring material on the sheet - aluminum sheet might work- I've been meaning to test it. In the real world a Webasto heats the floor (after manifold & run losses) to 115 F.
NeverEnough's approach to the problem is well worth study - http://www.expeditionportal.com/forum/threads/45835-C5500-TopKick-4x4-Crew-Cab-Build
He used electric radiant in his floors I think...certainly easier than hydronic. Moe
HY,
breathing, heating with propane creates moisture, in the winter is more evident due to cold surfaces and closed windows which traps the humidity inside. This is very bad for wood, matress, all other components. the only thing i've found is a mini dehumidifier on ebay, amazon. works on 12v , 3Amps and is thermoelectric(Peltier) like the 12v coolers. this could help absorbing the excess moisture
hope this helps
incognito
breathing, heating with propane creates moisture, in the winter is more evident due to cold surfaces and closed windows which traps the humidity inside. This is very bad for wood, matress, all other components. the only thing i've found is a mini dehumidifier on ebay, amazon. works on 12v , 3Amps and is thermoelectric(Peltier) like the 12v coolers. this could help absorbing the excess moisture
hope this helps
incognito