I've never used a sleeping bag liner as I never thought of layering a sleeping system like I do clothes.

Am I better off owning a 35 degree bag with a 15 degree liner? Or would a 20 degree bag be better?

If a new backpacker asks for a sleeping bag recommendation for 3 season camping, should we be recommending a single bag or a lighter weight bag plus a liner?

You might search this and other forums for this topic, as I know that it's been talked through extensively before (don't recall if here, though).

Opinions vary on temp ratings, and preferences vary on just using the things.

I don't know that it really helps you much to say that I prefer to not use a liner. More helpful, however, might be that everyone I know with any experience is confident that X ounces of extra down in your sleeping bag is a lot better than the equivalent weight of sleeping bag liner for keeping you warm.

I've used liners when I had to sleep in indoor situations (European huts) that required such, and I used one for quite a bit when I borrowed my wife's bag, just to keep it nice.

In the situation that you describe if it's anything close to weight neutral between those choices, I'd go with the 20 degree bag.

I agree with Brian! A few ounces extra down weighs less and is warmer than a liner!

I tried using one of those silk liners (the kind advertised to add 9*F to the bag's warmth). I got so tangled up in the thing (I toss and turn a lot) that it took me a couple of minutes to get out of my bag in the morning. After a few nights of that nonsense, I gave up the liner. I noticed no difference in warmth with or without it.

For me, a 20*F bag with a full-length zipper (so I can ventilate it on warm nights) is far better!

I agree with OM. I tried a liner, twice: first and last time. I also got tangled up in it.

For the same weight, take some lightweight long johns and sleep in them - you'll get just as much extra warmth with a lot less hassle, and you can wear them around camp or during the day if you need to. (If you're already carrying midweight longs, just layer the lightweights over or under them.)

With 3 against, I guess I'll pass. Thanks.

Gershon,

First time I did the AT I used an REI (I think) fleece liner in a substantial bivy as my only bag for the middle four months or so of the trip. Loved it cause it was easy to get in and out inside the bivy, and sometimes just slept on top. But it was way too heavy to carry in addition to a sleeping bag as a way to get a few more degrees. Better to get the bag you may need. The extra weight of the heavier bag will be considerably less than the weight of the liner I think mine weighed about 27 oz.

best,jcp

More down and no liner is the way to go most of the time IMO. However, I use the liner only as a way to keep my bag clean in the hot spring/summer/fall here in NC. I have 30deg. Montbell bag which is fairly light so the extra liner weight (5oz) is not too bad. I sleep with thermals or in my dry rain suit in the winter but in my birthday suit (TMI ) in the summer which can cause my bag to get a little grimy after many nights. Its hot and humid here in the South and dirt and sweat takes its toll. I usually sleep in the liner and use the bag as a quilt over top. works well for me because I can wash the silk time after time but not the down. But like its been said, if I were giving advice on strictly warmth...more down fill is the way to go.

I agree with this sentiment, but I find it amusing how if you read the for sale section (more so on BPL than here). That a majority of the bags for sale, people say they always used a liner with it. Nobody likes liners until they have to sell a bag and are trying to convince people its not yucky. lol

If I bought a second-hand sleeping bag, the first thing I'd do is wash it! (Using the instructions on the Western Mountaineering website for a down bag) Unless I knew the vendor personally, I wouldn't trust it even if he said it was freshly washed!

I am with everyone else on the it's more efficient to do more insulation in the bag that a liner. There are some variation though worth mentioning.

Vapor Barrier: if it's consistently below freezing (my experience is below 10F), a vapor barrier liner is worth it's weight for the warmth it adds and for it protecting your bag from slowly accumulating moisture from your perspiration.

Clothing as "liner". Rather than a liner, you might want to consider a mix of your bag + high loft clothing. You get better warmth / weight from your bag, but having some warm clothing which you can wear in camp, and then supplement your bag can be useful.

If you are doing a mix of winter and summer, doing an over bag and in inner bag can be useful. For a year I had a 30F down quilt which I used on warmer trips and as the inner insulation later on winter trips. I had a synthetic quilt which I used on wet trips and as an over bag in cold weather on the theory that on trips where moisture was a real issue, that the down quilt which is more susceptible to moisture would be protected by the synthetic quilt. This seems to work, but after year I found I still preferred a using a winter bag and got rid of the synthetic quilt.

--Mark