Quilt or sleeping bag, and what the temperature rating means

A bag or quilt with "20°F" on the label will not keep most people comfortable at 20°F. The number is usually a limit rating, the point at which a warm sleeper curled up is not yet at risk. The comfort rating is typically 5 to 10°F warmer. If the listing gives only one number, assume it is the optimistic one, and buy for the coldest night you expect plus a margin.

Quilts

A quilt has no back, no zipper and no hood, which is where a sleeping bag spends a lot of its weight. You lie on your pad and the quilt drapes over you. For a side sleeper who moves around, a quilt is more comfortable than a mummy bag. The trade is that a quilt depends completely on the pad underneath it, and in wind or below freezing it takes some technique to keep drafts out. Enlightened Equipment, Hammock Gear, Katabatic and Zenbivy make the ones you will find here.

Bags

A bag is simpler and more forgiving, and for anyone new to this it is the safer buy. Down bags from Feathered Friends and Western Mountaineering almost never go on sale, which tells you something about how they hold value. The bags that do show up at 30% to 50% off are from the larger brands clearing last year's models or colours. Those are good bags. Check the fill power and the fill weight, not the marketing name.

The pad is half the system

Insulation only works where it is not compressed, and under your body it is completely compressed. That is the pad's job. R-value is the number to look for: around 2 is summer, 3 to 4 covers three seasons for most people, and 5 and up is for snow. Pads go on sale far more often than bags do, and a higher R-value pad at 40% off is usually a better use of money than a warmer bag. The sleep deals page mixes both; the kit pages show the pad and the bag chosen together, which is how they should be bought.