A couple weekends ago I was in the white mountains near Lonesome Lake. My buddy and I ended up staying at the Lonesome Lake hut. We slept in a small room with two bunk beds. The temperature was somewhere between 20 and 25 degrees F. My sleep system was:
- North Face Cats Meow (rated 20° degree bag)
- JRB Shenandoah down quilt (rated 40°-45° F) on top for extra warmth
- Pillow and mattress provided by the hut

The hut's caretaker said she puts boiling (or near boiling water) in a nalgene bottle and sleeps with it between her legs so that it warms a major artery. Needless to say my friend and I both tried it out and it seemed to work nicely.

The next morning there was condensation on the inside of our room on the windows and the doors. I also then noticed that my quilt was damp and I noticed some wet spots and down clumping here and there (nothing serious but concerning). What was the cause? No ventilation in our room? The hot bottle in my bag during the night?

Thanks!

Edited by zalmen_mlotek on 11/15/2010 09:20:12 MST.

you down quilt should be under the synth bag ... not over

vapor will travel outwards ... thus to your quilt if its the last layer ... also the dew point was possibly in yr down quilt ... if you used yr synth bag over the quilt, the dew point would possibly have been there

use you JRB inside yr cats meow

Thanks for the simple solution.

The condensation in the room was likely cause by a few different factors, you guys breathing at night (the size of the cabin and ventilation factor in here), if you had any wet items you brought in that were drying out, and if you heated the water inside the cabin. I think you could make an argument that the heated water bottle increased your temperature which resulted in more perspiration/water loss which could then condensate, but I'd guess it's small compared to the other things.

Did you have the room all shut up at night for warmth? If so, where can the water vapour go? Try opening the window a bit. It won't solve the problem, but it should reduce it somewhat.

Yes - synthetic on the OUTSIDE!

Cheers