By Jay Motes
While mummy style sleeping bags are very popular, there are pros and cons of these bags for a buyer to consider before making a purchase. Mummy style sleeping bags are generally rounded at the top and tapered at the bottom to more closely fit the shape a person's body more tightly than a traditional rectangular sleeping bag. For a camper, backpacker or other person interested in buying a sleeping bag it is important to understand how mummy sleeping bags are different compared to a traditional sleeping bag.
Size and Weight
As a mummy sleeping bag is not as large as a traditional rectangular sleeping bag, a mummy bag is not as heavy and does not take up as much room as a rectangular sleeping bag. While the difference in size and weight is small, this small difference may be important for backpackers who carry their packs for long distances and others who need the smallest and lightest sleeping bag possible.
When using the same materials, mummy style sleeping bags will be warmer than a traditional rectangular sleeping bag as the mummy bag fits the body better and has less room for air in the bag. However, this difference is only important when winter camping, camping at higher elevations or other low temperature locations. For the average camper or backpacker who will only use the sleeping bag on summer camping trips, the slight warmth advantage of a mummy bag is irrelevant.
When made of similar materials the difference in comfort between a mummy sleeping bag and a standard sleeping bag is that the standard rectangular sleeping bag will have more room for the person to move around inside the bag. A rectangular bed can be completely unzipped and unfolded for use as a large blanket as well.
For a person needing to buy the most inexpensive sleeping bag possible, mummy style sleeping bags generally start at a higher price than a traditional sleeping bag. However, the difference is slight and only noticeable in the lowest price ranges of sleeping bags. Aside from the lowest priced models, most sleeping bag manufacturers sell bags of similar temperature ratings and materials for the same price regardless of whether the bag is rectangular or mummy style.