Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Sleeping bag liners

What is the general consensus on using a sleeping bag liner over, say your 15-20 degree bag to get yourself a 0-5 degree bag. I've never heard of anyone recommending bag liners for winter or cold weather camping. Here's a 15 degree liner I was looking at. Do they work? I'm suspect that it can warm as much as it says.

http://www.rei.com/product/705534

Thanks

Sleeping bag liner ratings are usually even more bogus than sleeping bag ratings. Expect 5 degrees or so of warmth, of that.

I use a silk liner mainly to keep my bag clean, but it's also a small bit warmer.

If you really want to sleep warmer, get a warmer bag and pad combo. If you just want to use your bag ocassionally on nights below the rating, there are several tricks to make you sleep warmer. Site selection, diet, wearing more clothing, etc.

I own that liner and use it with a 32 degree rated down bag. It definitely helps, but 15 degrees is a little optomistic - probably more like 5 degrees. That said, I like it a lot as it is very comfortable and takes up little space or weight.

I have one of those liners too. I agree completely with tiger. It helps but I don't think it adds a full 15 degrees.

Another trick I used before I got a 0F bag was to stuff a +40F bag into my +20F. As expected that turned out to be far more effective than a bag liner. It actually worked too well. At 10F I was burning up.

Ok, thanks, that's what I assumed.

Hey Rick, sounds like you've got the whole range in sleeping bags, +40, +20, 0. I thought I remember you saying you had a -40 bag as well. Is that correct?

I THROW IN A CHEMICAL HAND WARMER FOR MY FEET FOR MORE WARMTH.

everyone seems suspicious of the claim, but...

the ad didn't say 15 degree improvement over what? depends on your definition of what is is.

if you have a flimsy +40 bag, then adding almost anything could indeed get you that 15 degrees down to +25. That's not hard

Now if you have a zero degree bag, and want to climb Denali, then I'd rather have a much more serious bag to begin with instead of adding a liner.

since bags are passive heating devices, preheat them. the chemical pack is tiny and can roast you out. Another trick is to place really hot water from your cookstove into a Nalgene bottle
, tighten well, place inside your bag a half hour before sleep. You will be amazed how long this lasts.

Patrick,

Yes I think I have the entire temperature range covered:

+55F Coleman Fleece Bag/Blanket
+40F Marmot Atom
+30F Slumberjack cotton bag for car/campground camping
+20F WM Ultralight
0F Mountain Hardware Phantom 0
-30F WM Bighorn Super DL

I've become quite the gear whore. It's just annoying to have to skip a trip because you don't have the right gear. Don't even ask about tents. I have 5 tents (including an MH EV2 and EV3) and 2 bivys and I still feel like I need a better tent for summer stuff as well as a better solo 4 season tent. I've used the BD Lightsabre bivy more than anything else.

Btw, perhaps others can chime in here but it seems to me like my bivy tends to add a little warmth as well even though it has no insulation. So if you want to extend the warmth of your current bag a combination liner and bivy may help.

Rick, I'm sure you are right about the additive effect of a bivy. I think a tent helps, too, and I think they all work by blocking wind. The bivy has much less air inside to be heated, so probably is more efficient. I generally figure 5 degrees, but that probably varies.

I heard you gain up to 10 degrees inside a tent...though I guess there are plenty of variables that can effect this (tent, weather, # of people inside, etc)

Anways, I had a question about the sleeping bag liners...I was looking at them mainly just keep my bag clean inside but I was concerned with if there would be added bulk. That was kind of based off my assumption that you leave it in the bag when you pack it. Do you keep the liner in when you stuff your bag or do you remove it?

I have a Marmot Pinnacle (15deg) and it is plenty warm for what I have used it for...so i am not looking for added warmth but a liner would be nice for keeping it clean inside.

I use the REI silk liner -- under 5 oz, very thin. I leave it inside the bag and just stuff the bag. It does not take up any noticeable space.

Only problem with the silk, it has developed a rip where the label was sewn on. It is not the most durable fabric.