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01-28-2013, 11:49 AM
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#1
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4 Rivet Member
2017 23' International
Ridgefield
, Washington
Join Date: Oct 2010
Posts: 306
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Condensation / Humidity Woes!
Condensation and Humidity! The scourge of Airstreams.
How to control condensation and humidity in this beautiful aluminum cocoon?
In storage, we use Damp Rid units. On the road we use an electric powered dehumidifier. We rarely shower in our unit. However when the temps dip outside--only into the 40's e.g., we always experience window condensation which we perceive as a threat because of the volume of accumulated moisture and where it might drain! ....behind the insulation!
When we have camped in much lower temps, the condensation / moisture problems are compounded. How do winter campers handle these problems?
Thanks to all who can enlighten us. Zigi
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01-28-2013, 12:31 PM
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#2
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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Any Rv that has a watertight shell will have condensation problems, as well as many stick built houses. Modern houses solve the problem with air exchangers, which may not be practical for small RV's such as Airstream
But you must ventilate, even though there will be heat loss. Ventilate according to the activity and number of people. For example cooking produces lots of moisture, showers some, and of course breathing some.
We find by cracking the bedroom roof vent an inch at night and opening the shower and toilet vents, we have no moisture problems (in the dry Southwest). Using the range vent whenever cooking, plus a roof vent or two will do the trick.
Experiment, but ventilation is the answer.
doug k
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01-28-2013, 12:42 PM
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#3
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Figment of My Imagination
2012 Interstate Coach
From All Over
, More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
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Quote:
Originally Posted by Zigidachs
When we have camped in much lower temps, the condensation / moisture problems are compounded. How do winter campers handle these problems?
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Low-tech, low-cost method… Catch any condensation that forms before it drips where you don't want it. Roll up a towel and place it against the bottom edge of the window frame. When the towel gets too wet from dripping condensation, wring it out in the galley sink and replace it. If the window frames are too narrow to hold a towel, you can do the same with paper towels, except throw them away (in a bucket) and replace them with dry paper towels when they get too saturated.
__________________
I thought getting old would take longer!
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01-28-2013, 12:57 PM
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#4
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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Condensation is an issue but in most trailers, more moisture gets in from leaks than anything else. Ventilation is important as the others have said. De-Humidifiers are an excellent idea. Running the furnance with some ventilation is a good idea. The other day I ran the furnace and the AC for a while to dry things out. I will probably get a dehumidifier and drain it into the shower at some point.
Perry
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01-28-2013, 01:12 PM
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#5
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Figment of My Imagination
2012 Interstate Coach
From All Over
, More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
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Quote:
Originally Posted by perryg114
Condensation is an issue but in most trailers, more moisture gets in from leaks than anything else. Ventilation is important as the others have said. De-Humidifiers are an excellent idea. Running the furnance with some ventilation is a good idea. The other day I ran the furnace and the AC for a while to dry things out. I will probably get a dehumidifier and drain it into the shower at some point.
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Condensation happens when the temperature of a surface is lower than the dew point of the surrounding air. You can:
1 - heat the glass surface so it's warmer than the air's dew point;
2 - dry the air to lower the air's dew point;
3 - move the air so that individual water vapor molecules don't stay in contact with the glass for water to condense.
Interesting point, heating the air doesn't lower the dew point of the air, and you'll still get condensation as long as the outside of the trailer is cold, even if the inside air temperature is sweltering hot. Look at a glass of iced tea in the summer; same principle, hot air plus cold glass equals condensation. My previous suggestion was the same as putting down a coaster under a glass of iced tea; if you can't stop the condensation, catch it.
__________________
I thought getting old would take longer!
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01-28-2013, 01:24 PM
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#6
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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Trouble with catching condensation as a solution, is that in will form inside the shell due to all the penetrations for fixtures, window frames, vents, plumbing/electrical runs, and such.
It is most important to ventilate the moist air to the outside before it has a chance to collect on exposed and hidden surfaces.
doug k
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01-28-2013, 02:41 PM
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#7
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Figment of My Imagination
2012 Interstate Coach
From All Over
, More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
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Quote:
Originally Posted by dkottum
Trouble with catching condensation as a solution, is that in will form inside the shell due to all the penetrations for fixtures, window frames, vents, plumbing/electrical runs, and such.
It is most important to ventilate the moist air to the outside before it has a chance to collect on exposed and hidden surfaces.
doug k
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True, as long as the air coming in to replace it is drier than what he's venting out. But I figured there would already be plenty of responders saying, "Ventilate, ventilate, ventilate" and not too many others giving other alternatives.
__________________
I thought getting old would take longer!
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01-28-2013, 02:59 PM
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#8
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Rivet Master
1982 28' Airstream 280
Port Angeles
, Washington
Join Date: Aug 2008
Posts: 1,943
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Sopping up condensation dripping off the windows is kind of like putting a bucket under a leak. Ventilation will "fix" the leak before it drips in the bucket. We lived on our boat for ten years and vents open at sea in the rain will keep the boat dry inside.
__________________
Cheers, Dan
________________________________________
"Socialist governments traditionally do make a financial mess. They always run out of other people's money. It's quite a characteristic of them."
~ Margaret Thatcher ~
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01-28-2013, 03:02 PM
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#9
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Figment of My Imagination
2012 Interstate Coach
From All Over
, More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
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Quote:
Originally Posted by Smartstream
Sopping up condensation dripping off the windows is kind of like putting a bucket under a leak. Ventilation will "fix" the leak before it drips in the bucket. We lived on our boat for ten years and vents open at sea in the rain will keep the boat dry inside.
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But when I lived in a trailer in northern Maine 50 years ago as a kid, no amount of ventilation would stop the condensation when the temperature inside was above freezing and the temperature outside was below freezing.
Under those conditions, ventilation alone is not enough.
__________________
I thought getting old would take longer!
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01-28-2013, 04:44 PM
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#10
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Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
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You are correct. Heating the air in the trailer just allows water to evaporate and get it hot enough in there so the compressor on the AC runs to get rid of the water vapor. Also the furnance was right below where I just repaired a leak and I knew the insulation was wet there. Running the furnance helped dry the soaked insulation above it. I also had the bathroom vent fan running. The stove vent was the source of the recent leak and it has been removed for the time being.
Perry
Quote:
Originally Posted by Protagonist
Condensation happens when the temperature of a surface is lower than the dew point of the surrounding air. You can:
1 - heat the glass surface so it's warmer than the air's dew point;
2 - dry the air to lower the air's dew point;
3 - move the air so that individual water vapor molecules don't stay in contact with the glass for water to condense.
Interesting point, heating the air doesn't lower the dew point of the air, and you'll still get condensation as long as the outside of the trailer is cold, even if the inside air temperature is sweltering hot. Look at a glass of iced tea in the summer; same principle, hot air plus cold glass equals condensation. My previous suggestion was the same as putting down a coaster under a glass of iced tea; if you can't stop the condensation, catch it.
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