It is very important to bear in mind though that the temperature rankings are overviews for recommendation only. Because, much like spicy food, consuming a jalapeno pepper for some isn't really a big deal ... but for others eating one would certainly seem like it would melt the skin straight off their tongue. The exact same goes with a sleeping bag. A +20 level rating would indicate that for most the bag would certainly be cozy sufficient. The most effective way to pick a cozy enough bag is to go with one that handles a 10 degree chillier weather condition than what you're anticipating to be sleeping in. Selecting in that manner needs to have you ... covered. (No pun planned.) And once more of course, appropriate sleep wear should fit the chillier or warmer demands you may have.
The other sacrifice is the size or thickness of the bag. A mummy sleeping bag essentially will certainly be much smaller sized for bring around which is why it is a preference for many backpackers/hikers. The rectangular resting bag isn't as small yet because it's not common to be lugging it, apart from somewhere in a vehicle while getting to your intended location, the bulkiness of the bag is not as large a problem.
Primarily the term resting bag basically implies a protective bag for somebody to sleep in. A wet down sleeping bag is very hard to dry out as well as is considered even worse than having no resting bag at all. One more kind of resting bag is the mommy bag. Unless you are intending a trip to an extremely chilly climate and also resting outdoors after that you will most likely be better with rectangle-shaped sleeping bags over a mommy style bag. These bags have a particular usage and they are really certain, extremely cold climate, mommy sleeping bag.