You can place your sleeping bag around the hammock (below you) to keep from compressing the insulation, this is very warm and though you need an additional top insulation a small fleece will do the job if its not to cold. For this I use a kids sleeping bag (Thrift store) under me with string tied to the corners that runs up to the hammock ropes.No. That happens to be the one drawback of a hammock. Your sleeping bag will compress underneath you and make you cold from the bottom if it's actually cold out side. The kid who showed me how to make it carries a smaller thermarest which he swears works fine in the hammock and fixes this problem. I'll probably ditch mine for the winter. Or not. I'm staying way south as usual. They are seriously light. Basically just the weight of your biners if you use ripstop nylon. There is basically no excuse not to have one.