Question about using a sleeping bag liner for warmth

I keep seeing folks on trail and in reviews talk about adding a liner to their sleeping bag for extra warmth, but I think a lot of people are missing the point. In my experience, a basic silk or cotton liner adds maybe 5 degrees at most, and that's if you're lucky. Last October in the White Mountains, I brought a liner expecting it to save me on a cold night, and I was still freezing in my 20-degree bag. The real benefit, I've found, is keeping your bag clean and adding a bit of comfort, not a major temperature boost. If you need more warmth, you're better off with a quilt on top or a bag with a lower rating. Has anyone else tested this and found the same thing, or am I off base?

3 comments

3 Comments

blair_nguyen11d ago

Honestly... are we overthinking a piece of cloth? It's a thin sheet. If your bag is rated for 20 degrees and it's 15 out, no liner on earth will fix that math. I just use an old long sleeve shirt as a pillowcase and sleep in my clothes. Works fine and costs zero dollars. The whole liner thing feels like gear marketing to me.

ivanbell11d ago

But what about the long term wear on the bag itself? If you're using it for a week straight, that body oil and sweat has to go somewhere. My old down bag got kind of gross and flat after a season of trips where I just slept in my clothes. A cheap liner feels like a washable shield for the expensive bag. Isn't that the real point, not the extra five degrees?

mianelson11d ago

Totally agree about the real benefit being cleanliness. I used a liner on the Colorado Trail last summer and it was a game changer for keeping sweat and dirt out of my bag over a long stretch. But yeah, for warmth it felt like nothing. I ended up just wearing my puffy jacket inside the bag on the cold nights, which worked way better than any thin liner ever could.