I’ve been testing a pair of Warmlite Vapor Barrier Socks since November as a replacement for the Integral Designs Vapor Barrier Socks I used last year. While they are a huge improvement in terms of effectiveness, the sewing workmanship is substandard so I really can’t recommend the product to anyone. That’s a shame because these socks have reaffirmed my belief in the effectiveness of using vapor barrier liners as part of my mountaineering and winter boot system boot system. I just wish I didn’t have to resew the seams when they come apart.

Vapor Barrier Clothing

Vapor barrier clothing is an alternative layering system for winter clothing that is designed to stop you from sweating and wetting out your clothing layers. It’s best used in very cold temperatures (10 degrees fahrenheit or less) when you need to wear the same clothes or insulated socks for days at a time and can’t dry them at night.

This is very different from the layering principle which most winter hikers are taught, which is to wear several layers of clothing so that sweat moves from your baselayers to your outer layers where it can evaporate without chilling you.

In practice, you can mix and match the two techniques using vapor barrier glove liners under your mittens and vapor barrier socks in your boots, while using a layering approach for your legs, head, and torso. That’s what I do since my hands and feet sweat uncontrollably on winter hikes, while I can manage my level of leg and torso sweat pretty well by taking off layers when I’m hot and putting them back on when I’m cold.

Fuzzy Stuff Socks

Stephenson’s Warmlite vapor barrier socks are made out a material they call “fuzzy stuff”, a knitted nylon fabric that is coated with urethane on one side. The socks are made with two layers of fuzzy stuff sewn with the urethane coating facing in, so it doesn’t wear off too quickly. The pattern is really simple and almost clownish, with the seams running on the outside of the sock to prevent rubbing – friction – and blisters.

A Winter Boot “System”

While you can wear vapor barrier socks directly against your skin, a lot of people prefer wearing them over thin sock liners for more comfort because your feet do sweat under them, although much less than you’d think. For example, when I wear mountaineering boots, I typically pull the vapor barrier sock over the sock liner and then put on a mid-weight wool sock for insulation. The next layer is an Intuition foam boot liner if I’m wearing my plastic mountaineering boots (rated to -30 F) or an unlined mountaineering boot in warmer weather.

When I sweat, all of the moisture is trapped underneath the vapor barrier sock, which keeps all of the layers above it completely dry. This makes a huge difference on multi-day winter hikes because it eliminates the need to sleep with your boot liners or wool socks in your sleeping bag to prevent them from freezing at night and to dry them out. Not only is this more comfortable, but it means that that there will be less moisture trapped in your sleeping bag’s insulation and less loft/insulation loss.

Vapor barrier liners also create a warm micro-climate around your skin, trapping your own body heat close to it so you feel warmer with less insulation. They also prevent smells from migrating into your clothes, which can be a boon if your body odor bothers you.

Product Quality Issues

At $8/pair Stephenson’s Warmlite Vapor Barrier Socks are not expensive. But I don’t think that excuses the product quality issues I’ve experienced using them. It’s gotten to the point where I’ve stopped calling Stephenson’s to ask for replacement socks when the seams blow out because they were sewn too close to the edge of the fabric. It’s really too bad because these vapor barrier socks work when the seams are intact, they’re comfortable to wear, and easy to hand wash. It’s just a waste of my time to have to resew them every trip or two and I’d rather have a product that is more expensive, better sewn, and more durable.

Disclosure: Philip Werner (SectionHiker.com) purchased this product with his own funds.