Newbie Condinsation?

[bmwrider]

I'm trying to understand where the water vapor condenses when using an under quilt, I have never used a UQ before, I understand it in terms of a sleeping pad and tent, I have always found it under my pad when winter camping, but with a hammock your not in direct contact with the ground and I would like to know where it hapens and the methods used to prevent it or should I say deal with it.

[angrysparrow]

I'm trying to understand where the water vapor condenses when using an under quilt, I have never used a UQ before, I understand it in terms of a sleeping pad and tent, I have always found it under my pad when winter camping, but with a hammock your not in direct contact with the ground and I would like to know where it hapens and the methods used to prevent it or should I say deal with it.

Generally speaking, there should be none. Most underquilts are made with breathable fabric so they don't collect any moisture. Unless you add a vapor barrier layer to your insulation (or have an UQ made with a non-breathable shell), your body heat will either evaporate any moisture or force it all the way through the layers to exit.

Avoiding condensation is what led the Jacks (JRB) to make the first underquilt prototypes around 2005.

Here is a good thread about the topic.

[Buffalo Skipper]

I have never had any consensation in/on my underquilts. I always use an underquilt, in temps from the low 20s up to the upper 70s. My winter quilt is down; my summer quilt is Climashield.

Condensation occurs when there is a vapor barrier, such as a pad. Others with more experience can add to this.

[BillyBob58]

What you saw under your pad( presumably a vapor barrier) was probably not condensation, but snow or ice melt from however much body heat managed to make it through the pad causing some melt. Also, sometimes moisture on your side of a pad/UQ/space blanket or in a quilt is not always condensation, but sweat due to being TOO warm.

Condensation will occur when moisture in the form of vapor leaves your body(skin or breath) and contacts a surface or air which is below the dew point. So your breath(vapor) can leave your nose/mouth, contacts the ice cold neck area of your quilt or bag, and condense into liquid. Or it can travel from your body, through the insulation of your quilt until it reaches outer insulation that is cold enough, or maybe all the way to the cold quilt shell, and condense there.

But most often it will travel all the way to the outside of the quilt before it condenses. For example, after camping the other night at ~37/38F, I weighed my TQ and UQ, and there was no apparent weight increase.

Other times, on longer or colder(or both) trips, I have seen peoples down bags slowly loose loft(warmth) even though zero rain/snow contacted them. It appears this was from condensation. A vapor barrier can- in my experience- cut way down on this problem, even if you are actually damper right at your skin.

[HappyHiker]

+1 to Billybob - excellent answer.

[Caribou Bentspoke]

I live in a area of high humidity even in summer, and have never seen moisture in an UQ, but when I tent camped everything was wet. Being above ground has many advantages.

[bmwrider]

What you saw under your pad( presumably a vapor barrier) was probably not condensation, but snow or ice melt from however much body heat managed to make it through the pad causing some melt. Also, sometimes moisture on your side of a pad/UQ/space blanket or in a quilt is not always condensation, but sweat due to being TOO warm.

Condensation will occur when moisture in the form of vapor leaves your body(skin or breath) and contacts a surface or air which is below the dew point. So your breath(vapor) can leave your nose/mouth, contacts the ice cold neck area of your quilt or bag, and condense into liquid. Or it can travel from your body, through the insulation of your quilt until it reaches outer insulation that is cold enough, or maybe all the way to the cold quilt shell, and condense there.

But most often it will travel all the way to the outside of the quilt before it condenses. For example, after camping the other night at ~37/38F, I weighed my TQ and UQ, and there was no apparent weight increase.

Other times, on longer or colder(or both) trips, I have seen peoples down bags slowly loose loft(warmth) even though zero rain/snow contacted them. It appears this was from condensation. A vapor barrier can- in my experience- cut way down on this problem, even if you are actually damper right at your skin.

that is helpful, thank you