Insultex Breathable...really?

[Rat]

It is important to remember how 'breathable' fabric is rated. Our old friend Goretex, largely accepted as the top rated waterproof breathable fabric out there, only allows a permeation of about 3% under the best of conditions.

Waterproof breathable fabrics are rated at a stated humidity and pressure difference; IOW if the pressure inside the 'rain suit' and the pressure outside the rainsuit (Atmo) are the same the breathability is much less, additionally if the humidity is close to the same inside and outside the breathability plunges even further.

This is why you will sweat in a 'breathable' rainsuit; most of the breathability claims are hype. 3% or even 5% isn't much and you need to really watch your activity level or end up soaked in the $300 'breathable' rain gear. I have touted the benefits of venting over breathability for years, even here on HF. And the fact is that any material that is waterproof/windproof will collect condensation under the right circumstances.

Originally Posted by canoebie View Post
I do not view IX as "breathable" nor do I view it as a complete vapor barrier.

This is true of any 'breathable' waterproof/windproof fabric.

Even my beloved Frogg Toggs have a problem above about 60 degrees keeping me dry from sweat; I really need to put some vent zips in them to be truly effective.

[slowhike]

It is important to remember how 'breathable' fabric is rated. Our old friend Goretex, largely accepted as the top rated waterproof breathable fabric out there, only allows a permeation of about 3% under the best of conditions.

Waterproof breathable fabrics are rated at a stated humidity and pressure difference; IOW if the pressure inside the 'rain suit' and the pressure outside the rainsuit (Atmo) are the same the breathability is much less, additionally if the humidity is close to the same inside and outside the breathability plunges even further.

This is why you will sweat in a 'breathable' rainsuit; most of the breathability claims are hype. 3% or even 5% isn't much and you need to really watch your activity level or end up soaked in the $300 'breathable' rain gear. I have touted the benefits of venting over breathability for years, even here on HF. And the fact is that any material that is waterproof/windproof will collect condensation under the right circumstances.


This is true of any 'breathable' waterproof/windproof fabric.

Even my beloved Frogg Toggs have a problem above about 60 degrees keeping me dry from sweat; I really need to put some vent zips in them to be truly effective.

So what you're saying is that the more waterproof a material is, the less breathable, & vise versa?
So if a person wanted to break it down in a way that a simpleton (me) could understand it, they might say...
If it's 70%waterproof, it's only 30% breathable.
If you want it more breathable you need to find a material that is closer to 70% breathable & 30% waterproof.
Right?

[canoebie]

That response (Rat) is very helpful and I think it makes sense. What amazes me about IX is the insulation properties, I do think an airspace to allow moisture to "move" a bit without a draft makes it more effective and less likely to condensate.

[Doctari]

So far, for me the only similar experience was on a 45+ night, I got WAY too hot, & like Knotty, I found a puddle in the 1X. BUT, that wasn't from condensation, it was from sweat Yea, I know "YUCK"
So far in the cooler temps, I havn't had a noticable problem with pooling due to condensation. But I'm likely more ventilated during the cooler temps then most, I don't do heat very well & will often open up everything to ventilate, even in sub freezing temps.
So my take on this is: the 1X is waterproof, so if there is moisture it can pool, but a good way to stay warm is to stay slightly cool, therefore DRY.

[G...Hawk]

I've used a 3 layer Insultex under quilt and 3 layer Insultex top quilt and never had any condensation issues. I use the Insultex encased in nylon shells and no other insulation other than the clothes I'm wearing. Maybe the nylon shells make a difference somehow?? Don't immediately see how, but stranger things have happened to me.

Also have 3 layers IX+1 layer ripstop : TQ and UQ.

3 of last 4 nights hanging ( on the AT ) were dry. One night the feel of moisture, not seen, inside TQ ( dome-like, covering my head ).

Think : when next it begins to feel moist, will experiment with turning TQ over and have IX on the outside.
ALso, Will use 12"sq fleece as moisture collector near breath.
( Sewed a 3" band of ripstop at the top of the IX to give a nicer texture at the top near my face. )

[Just Jeff]

Don't hammock socks already have problems with condensation, because of exhaled breath? Maybe they just consider it par for the course...

This isn't my experience at all. I've used three different versions of DWR hammock socks, in conditions from below zero to about 60F, and have very rarely had any problems with condensation. A couple times when the condensation did get bad in the sock, it was bad for everyone...so it's not a weakness in the sock per se, just that the sock wasn't the best gear choice for those conditions.

One time, for example, I had my 8 y/o son inside the sock with me and a freezing fog blew thru the camp. I woke up with our breath frozen along the top of the sock...partly b/c it was so humid outside that the moisture had trouble passing thru, and partly b/c it was so cold outside that the moisture froze almost on contact with the DWR.

So in specific cases, moisture can be a problem with hammock socks but overall I wouldn't call condensation problems par for the course.

[Rat]

So what you're saying is that the more waterproof a material is, the less breathable, & vise versa?
So if a person wanted to break it down in a way that a simpleton (me) could understand it, they might say...
If it's 70%waterproof, it's only 30% breathable.
If you want it more breathable you need to find a material that is closer to 70% breathable & 30% waterproof.
Right?

Yes, but you will never find a waterproof material that approaches 30% breathability under normal conditions. The main thing to remember is that under the conditions we are going to wear rain gear in MOST of the time, 50 degrees and 100% RH (Raining), your rain gear isn't going to be very breathable if you are moving. Two things happen; 1) you build up too much moisture too fast. The membrane can only allow a certain amount through under certain conditions. Your sensible and insensible perspiration during active times will always overburden the membrane's ability to move moisture. 2) Once vapor has condensed into a liquid, you need to evaporate it for it too pass through the membrane. If the temperature is cold enough the vapor will condense on the underside of the membrane if the membrane is overburdened. Because the rain shell is the last layer it is less likely to evaporate and pass through.

My Frogg Toggs, which is about the most breathable stuff I have found, get me wet at anything over 60 degrees in light activity (walking, no load). Obviously each person physiology is going to play a role, but for me it's either a poncho or rain gear with plenty of zippered ventilation.

[Knotty]

It is important to remember how 'breathable' fabric is rated. Our old friend Goretex, largely accepted as the top rated waterproof breathable fabric out there, only allows a permeation of about 3% under the best of conditions.

Waterproof breathable fabrics are rated at a stated humidity and pressure difference; IOW if the pressure inside the 'rain suit' and the pressure outside the rainsuit (Atmo) are the same the breathability is much less, additionally if the humidity is close to the same inside and outside the breathability plunges even further.

This is why you will sweat in a 'breathable' rainsuit; most of the breathability claims are hype. 3% or even 5% isn't much and you need to really watch your activity level or end up soaked in the $300 'breathable' rain gear. I have touted the benefits of venting over breathability for years, even here on HF. And the fact is that any material that is waterproof/windproof will collect condensation under the right circumstances.


This is true of any 'breathable' waterproof/windproof fabric.

Even my beloved Frogg Toggs have a problem above about 60 degrees keeping me dry from sweat; I really need to put some vent zips in them to be truly effective.

Breathable definitely comes in degrees. The intent of this discussion was to uncover if IX breathes enough to be used as a cold-side insulation layer. Based on the experience I had, and some logic, I'm not sure it can be. In most insulation systems, the vapor barrier must be used on the warm-side, so that the temps are still high enough to avoid excessive condensation. I could have hung the weathershield looser. That would have helped with wind stealing heat from the down underneath but there would have been less purely inulsative benefit.

I hope you don't mind if I inquire further...

Was the down damp?

What did you have on top of you?

What would you estimate for the wind, temp and humidity?

You said you were toasty... would you say that you were warmer than necessary, or just right?

I couldn't tell if the down UQ was damp. Over me I had a GoLite 20F 3 Season TQ.

Temps in mid-thirties. Humidity unknown. Wind 5-10MPH.

I was never uncomfortably hot but I normally sleep cold so I was enjoying the warmth.

[Rat]

This isn't my experience at all. I've used three different versions of DWR hammock socks, in conditions from below zero to about 60F, and have very rarely had any problems with condensation. A couple times when the condensation did get bad in the sock, it was bad for everyone...so it's not a weakness in the sock per se, just that the sock wasn't the best gear choice for those conditions.

One time, for example, I had my 8 y/o son inside the sock with me and a freezing fog blew thru the camp. I woke up with our breath frozen along the top of the sock...partly b/c it was so humid outside that the moisture had trouble passing thru, and partly b/c it was so cold outside that the moisture froze almost on contact with the DWR.

So in specific cases, moisture can be a problem with hammock socks but overall I wouldn't call condensation problems par for the course.

There are a pretty specific set of rules for condensation to occur. First, there needs to be a surface that is at, or below, the dew point temperature of the surrounding air; Second, there has to be air surrounding an object that has a dew point at or higher than the object.

So the air outside the sock needs to be cool enough to be below the dew point of the air inside the sock for condensation to occure. By venting we are adding dilution air (lower temp and/or RH) to the process, and, hopefully, moving the moisture laden air out as well to counteract condensation.

You can have condensation occur at one time and not another using the same materials. For Example:

With a dry bulb temp of 60 degrees
RH of 80%
We have a dew point of 54 degrees

Move these down a few degrees and see what happens:
Dry bulb of 50 degrees
RH of 60%
Dew point of 37 degrees.

In each of the cases above with an ambient (outside) temperature of 45 degrees: In case one we condensation occurring in case two we do not. The only variables are the environmental conditions, not the type of material the sock is made from.

[MacEntyre]

I couldn't tell if the down UQ was damp.

So it really wasn't a problem, eh?

I bet what Canobie said would prevent condensation in that case... one more layer with space between them. Perhaps you would have a less drastic temp gradient across the IX.