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.
Goose Down Resting Bag: There's nothing with a greater weight to warmth proportion when compared with down. A Goose Down resting bag is extremely light-weight. Down is only for people most diligent in maintaining their sleeping bag completely dry. Hood: as detailed previously with the Mummy Sleeping Bag, a hood having a drawstring could assist keep temperature.
If you see a +20 degree score that would certainly indicate that the bag should be cozy enough for temperatures that are 20 levels or warmer.. And if you see a - 20 level score then it has actually been figured out that the bag needs to be cozy sufficient for minus 20 degree climate.