Turns out layering works with sleeping gear just as it does with t-shirts and jackets – the perfect warmth factor, maximum outdoor comfort, can be achieved by using different gradations of materials and thicknesses. The problem is, one good sleeping bag is hard enough and expensive enough to come by, let alone a variety of different lofts and temperature ratings. The solution – sleeping bag liners.
Liners quickly extend the season range of a sleeping bag, transforming summer bags into spring/fall bags, California 3-season bags into Minnesota ones. Add 2 liners to a 20° bag for warm cold-winter sleeping.
Sleeping bag liners range in price from about $20 to $80, in weight from 7 oz to 2 lbs, and some claim to add as much as 10° of warmth, depending on the material and thickness. Here are a few popular options:
|Make/Model||Material||Weight||Pack Size||Avg Price|
|Cocoon coolmax||Coolmax||11 oz||3.5” × 7”||$40|
|Kelty 100||Fleece||1 lb 9 oz||7” × 14”||$35|
|Sea to Summit||Silk||7 oz||3” × 5.5”||$65|
|Slumberjack||Micro fleece||1 lb 1 oz||5” × 11”||$65|
Without insulation, i.e., with only a single layer of fabric, warmth depends mostly on weight – the heavier the fabric the warmer you’ll be. Higher prices come with the more comfortable or moisture-wicking fabrics.
The final option is to make your own liner, which is as easy as sewing two pieces of fabric together, since that’s all a liner is. The fleece liner above took 15 minutes, cost nothing (I reused an old blanket), fits well, and weighs 12 oz. I tested it out this weekend in the Sand Dunes State Forest.
A homemade liner is ideal for the youngsters, since cold-weather bags for kids are rare and kid-sized liners nonexistent.