Can sleeping bag liners be used as ultralight
sleeping bags, or do they require the insulation of a bag in order to be
I’ve used sleeping bag liners solo on really hot steamy summer nights (like 70°F and above), but if it turns nippy at all, you might be left shivering. One good (and ultralight) alternative is to pack a liner bag and an insulated quilt like the Therm-a-Rest Tech Blanket. It’s a synthetic-insulated blanket that packs up small and only costs 50 bucks. Depending on how you sleep, it will likely keep you comfy down to 45°F or so, but you can also opt for puffier down versions that cost more and pack more heat.