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Sleeping Bag Liner

Is there a sleeping bag liner that will add 10/15 degrees? I will be in 30 degree weather. I have read mixed reviews so I'm trying to decide if I should spend my money on one. If so, can you recommend one? Thanks 🙂

6 Replies

@mschristine Thanks for reaching out!

Sleeping bag liners are one of several good ways to add some degrees of warmth to your sleeping bag! Because of the variabilities in a person’s metabolism and body type, the temperature ratings can be very subjective. We have several sleeping bag liners that offer +10 degrees or ‘adding a season of warmth’ to your sleeping bag. You can find a couple examples here and here.

A couple of other tips I always keep in mind when thinking about warmth in my sleeping bag:

  1. Extra space in my sleeping bag will make my body work harder to stay warm. Can I fill that space with extra clothes or a blanket? This is particularly useful with a rectangular sleeping bag.
  2. Am I warm when I get into my sleeping bag? It seems obvious, but a sleeping bag won’t make you warm, it simply insulates and traps the heat that is inside it. Before I get into my sleeping bag, I try to make sure that I am warm by walking around, doing jumping jacks, or even sit-ups. That gets my heart pumping a little bit and ensures that I’m starting out warm. Additionally you can fill a water bottle with warm or hot water and keep it in the sleeping bag with you. Just make sure it’s not too hot!
  3. Do I need added insulation underneath my sleeping bag? This is particularly useful when sleeping on frozen ground or snow. A closed cell foam mattress pad is your best bet when looking for insulation from frozen ground.

I hope this helps, best of luck!


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I'm a big fan of the Sea to Summit brand and happily use both their extreme and compact liners to extend the range of my synthetic Mtn Hdware 30deg bag well into the mid and lower '20's. They're advertised to add between 20-25 degrees of warmth.  I've experienced temps in the 18-20 range with  the extreme and that was about the limit for me, so not quite the additional 20+.  Admittedly I'm a warm sleeper and that's probably worth another few deg, but these liners easily extend my summer bag well into the shoulder seasons.  I was very skeptical at first due to the material thinness.  But having that Thermolite layer inside my bag really made a surprising difference.  I personally don't like fleece liners as they tend to generate static electricity as I roll-around at night and get all clingy and annoying - esp in low humidity.

I also have their Coolmax liner that's used in the summer - no warmth but def helps wick away moisture and keeps my bag cleaner.

A good bag + a good liner = a wide range of temp options.

Sleeping bag liners are a mixed bag and if you move around much in your sleep that is what you end up with or so l am reliably informed by people I know who have tried them.  Its worth a try but I would definate try it out before you go and make sure it will work for you before typing yourself on knots in the backcountry.  I would also research just getting a better bag. 

As pointed out, don't overlook your sleeping pad since that makes a big difference.  Check your current pad and consider upgrading if it is not very insulating. Some people double up an inflatable with a closed foam for winter use when camping on snow.

why not put on a pair of long johns T&B to sleep in? (silk or poly pro) And don't forget the balaclava on your head (silk or fleece). 


I use a silk liner sometimes in my 32* REI bag but a couple of hand warmers will get you through the night also.  I put one by my feet and replace it several hours later.  Not a great solution for a many-day trip as they are not lightweight if you have to carry several.


I've used a sleeping bag liner before (Sea to Summit Thermolite Reactor Extreme Mummy Bag Liner), but haven't had much luck with it making me feel warmer. What I've found it just makes me feel uncomfortable, yet my husband swears by his (the same brand). Like @REI-JohnJ mentioned, the warmth added is very subjective. 

I do fill the cavities in my bag with whatever clothing I have, and I will try to do some sort of activity that will warm me up before getting into my bag. Sometimes I'll wiggle around or rub my legs together and my arms against my body to create friction heat while inside the bat), and the bag will do the job of trapping that heat generated. I also have a Therm-a-Rest NeoAir XTherm Sleeping Pad to insulate myself from the cold ground. Still, if camping on frozen ground, I would probably use a closed-cell foam mattress underneath the inflatable pad because I'm a side-sleeper, and my hips hurt on just the foam mattress. 

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