MEC Merlin Sleeping Bag
Merlin Sleeping Bag

Do I really need a liner and/or a vapor barrier for my sleeping bag?

I’m climbing Kilimanjaro this summer. Does it make sense to use a silk liner on the inside of my sleeping bag and a vapor barrier liner on the outside of the bag? Lauren Edmonton, Alberta

MEC Merlin Sleeping Bag

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

There are two parts to the answer of this question. The first part: No, that really won’t work so well. Vapor barrier liners work by reducing evaporative cooling, the cooling that comes from moisture on your skin as it, well, evaporates. So you need that layer very close to your skin, not outside of the bag. The proper sequence would be: You’re inside the vapor barrier liner, the silk liner goes outside of the vapor barrier liner, and then the bag goes over all of that.

MEC Merlin Sleeping Bag

MEC Merlin Sleeping Bag Merlin Sleeping Bag

The second part: Do you really think you need that much stuff? It does get cold on Kilimanjaro, but nighttime temps aren’t going to dip much below -10 C (15 F). Most any good three-season sleeping bag, maybe with a silk liner, should be adequate for that. Marmot’s Helium (US$359) would be perfect. It weighs just under two pounds, has 850-fill down, and is a good-fitting bag. The silk liner would take that down to -15 C.

Up your way, MEC sells a house-brand bag called the Merlin (C$260), a -10 C bag that has down fill and a stripped-down design for light weight (33 ounces, so a touch less than the Helium). Nice bag!

Hope you have a good trip; everyone who goes loves it. Just take lots of hand sanitizer.

The 2008 Summer Outside Buyer’s Guide is now online. From riding to trail-running to camping, get reviews of nearly 400 gear must-haves.

Trending on Outside Online