Thread: Condensation on Sleeping Bag

Originally Posted by mopheadrob

Just to clarify, I don’t think it will be moisture from the outside air, as this would only condense on cooler surfaces (think beer cans). What’s happening is interstitial condensation, similar to what happens in the walls of a house.

Air heated by your body gets drawn to the outside, taking vapour with it. As it contacts the outside it cools and can’t hold as much water, so it dumps it. Look up ‘relative humidity’.

If you’ve got condensation on the outside then the bag is doing it’s job, and not allowing it to wick back into the absorbent filling. More of a worry if the condensation occurs on the inside of the outer shell.

You should dry it as early as possible though, DWR coatings can only do so much. If you must pack it up damp, then take it out as soon as you set up your next camp.

I agree with @mopheadrob. If the 'moisture' is not the result of masturbation and flatulence then it must be condensation, formed when the warm moist air hits the 'dew point' on the cold outside of the bag. A solution would be to lay a brush cotton sheet over the bag while sleeping which will slightly insulate the outside of the bag thus moving the 'dew point' to the top surface of the sheet instead of the bag. You will have a wet sheet in the morning but a dry bag, you dirty depraved deer shagger.