Why I use vapor barrier inner in my quilts?

In this post I will talk about the following:

1) What is the problem I am trying to solve?
2) What is a vapor barrier?
3) What are the advantages of vapor barrier inner?
4) What are the potential issues and how I fixed them?

Ready to dive in? Let's begin.

1) What is the problem I am trying to solve?
The problem is that sleeping bags get cold and wet because of internal condensation when hiking/camping in bad weather (i.e., wet and cold conditions). This moisture which comes from your sweat and wet clothes compromises the thermal efficiency of the sleeping bag and can result in you feeling cold and may be getting sick.

Examples of possible conditions prone to condensation:

  • Sleeping in the open under the stars
  • Sleeping in a tent while its rain or snowing
  • Very cold conditions
  • Using single wall tent in windless conditions

2) What is a Vapor barrier?

Vapor barrier is a non-breathable inner fabric that keeps internal moisture off your insulation – keeping you dry, warm and comfortable in bad weather.

3) What are the advantages of vapor barrier inner?

Vapor barrier liner bags and clothing are used by polar explorers, as well as long-distance hikers in winters. It protects the bags from frost and condensation, a life-threatening situation in cold, remote conditions.

I have extended the application of vapor barrier to 3 season by integrating a vapor barrier inner in a quilt design along with breathable draft stoppers and zippered foot box.

    • DRY Prevents your bag from getting damp due to condensation
    • WARMTH Vapor barrier adds 10-15F warmth at no additional weight by minimizing conductive, convective and evaporative heat loss.
    • WINDPROOF Without vapor barrier, your quilt / bag needs highly air permeable shell which is not very windproof. This means you need to carry a bivvy if sleeping in the open. Blue Bolt vapor barrier quilts use a windproof shell and breathable draft stopper, so you can skip the bivvy in good weather.
    • NO CLAMMINESS Unlike vapor barrier clothing or liner bags, the moisture in vapor barrier quilts can still breath out through the breathable draft stopper thus preventing that uncomfortable clammy feeling.
    • LAYERING With vapor barrier quilts you can layer clothing inside the quilt.



      4) What are the usual issues when using vapor barrier liners and clothing and how I fixed them in the my vapor barrier quilt design?

      Problem 1 - Clammy feeling

      The problem with vapor barrier liner bags and clothing is that it can feel clammy, so most hikers avoid it unless it's critical such as if they are hiking long distance in remote areas.

      Problem 2 - Layering issue

      Layering inside a vapor barrier liner bag is not possible as all the layers will get soaked from sweat.

      I solved both these issues by integrating vapor barrier inner and breathable draft stopper in the quilt design which allowed the moisture inside to breath out through the draft stopper. This quilt has been tested 3000 km /120 passes in Indian Himalayas by Peter Van Geit and he found no condensation or clamminess issues.

      Next, I have also incorporated a zippered foot box which can be opened completely in warmer weather.


      Do you find the concept intriguing? Or hard to believe? I would like to offer you an opportunity to field test the quilt. Your purchase will come with a 60 days risk-free trial period. You can return the quilt back for a full refund if it doesn't work for you..


      * I can customize a quilt with a breathable inner by request.

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