Choosing the right sleeping bag is not as simple as it would first appear. There are a number of varieties and variations on the market. Choosing the right sleeping bag is not as simple as it would first appear. There are a number of varieties and variations on the market. To simplify the process we look at two basic styles into which most designs will be either one or the other: rectangular sleeping bags (commonly called square bags) and mummy style sleeping bags.What Square and Mummy Style Bags Have in CommonThe immediate and fairly obvious answer is that both are designed to give you the best night’s sleep possible. But each approaches the task in similar but subtly different ways.Both styles of sleeping bag have outer shells made from materials such as nylon, polyester, and microfibre. While microfiber has the softest feel, ripstop nylon is the most durable. The outer shell has a denier count sufficient to make it water-resistant.Depending on where and how you travel, or how much rough and tumble your sleeping bag must endure, will determine the outer shell material. The construction of the sleeping bag is not immediately apparent when searching the shelves of a camping supply store or buying online. Sewn-through technique is a simple way to make a sleeping bag where filling is trapped in place by sewing seams through the out layer joining the inner layer. As a rule, you will find this method in budget bags. Shingle and baffles construction holds the insulating material inside channels to stop it shifting about creating cold spots. This method is used in hollow-fill polyester insulation and the more expensive down filled bags. Both square and mummy style sleeping bags are made with a choice of synthetic fill or feather down. Rectangular Sleeping BagsRectangular sleeping bags are the traditional shape. They are roomy and perfectly suited for some situation, but not so good in others.Rectangular or square bags have the advantage of being a shape easily folded; that is, they can be folded in half and half again before being compressed to fit into a stuffing bag. Mummy bags need to be folded then rolled into a compressed shape. Rectangular bags are uniform from head to toe. It means freedom for feet and knees to move about. Also bear in mind, side sleepers can fold their knees up to their preferred sleeping position. Finally, those situations where two must share is doable in a rectangular bag due all round zippers, but impossible in mummy style bags. The advantages of a rectangular style bag:The ProsHas full length zippers usually all the way round and can be opened up as a quilt.Larger size is more comfortable for large framed folk.Better sleeping position can be achieved because of the uniform width.The ConsMore room inside the bag requires greater body heat to generate warmth.Because more materials are needed for the shape, square bags tend to be heavier and not a good choice for backpackers. Not the best choice for sub-zero camping. <a href= “https://wenzelco.com/grande-0/”>The Wenzel Grande</a>Covered with 8 ounce cotton and filled with 6.5 Insul-Therm® to stay warm when the temperature drops.<a href= “http://www.nemoequipment.com/product/?p=Strato%20Loft”>Strato Loft Down Sleeping Bag</a>More of a sleeping system than merely a bag, the Strato Loft incorporates an uninsulated sleeve to fit a sleeping pad.<a href= “https://slumberjack.com/country-squire-20/”>The Country Squire 20</a>The Country Squire includes a poly-cotton liner as an additional layer to be removed when the weather is warmer.When it comes to warmth, mummy style bags have the edge:The Pros:Contoured to body shapes means less gap between insulation and body heat.Often filled with down making them lightweight and very compact.Can handle sub-zero temperatures.Built draw-string hood to seal in warmth and keep out drafts.The Cons:Zipper is mostly down to midriff. Single sleeping only.Restricted sleeping position and can feel closed-in, straitjacket confinement. Mummy bags are purposely designed to be lightweight with quality synthetic or down insulation with the best weight to loft protection from the cold. They are also intended to compress into small shapes ideal for inside, or hung from backpacks. Mummy style bags would be a suitable choice for bikepackers and hikers. While rectangular bags have the advantage of a better choice of sleeping positions over mummy style bag– mostly suited to back sleepers–many argue this point. Side sleepers in mummy bags claim they are comfortable in rolling over taking the entire bag with them. It means the bag also lies on its side. There are benefits to each and testing both in a store may be preferable to buying online. <a href= “https://www.rei.com/product/107168/marmot-trestles-20-elite-sleeping-bag-mens?cm_mmc=aff_AL-_-145262-_-180150-_-NA&avad=180150_df3d5d15”>Marmot Trestles 20 Elite Sleeping Bag-Men’s</a>The Marmot Trestles has a unique blend of 3 fibers ensuring best protection from cold air. It also features wave construction for maximum loft on the top and a blanket built on the bottom for exceptional comfort. <a href= “https://www.kelty.com/cosmic-20/”>Kelty’s Cosmic 20</a>The Cosmic 20 is a serious three-season sleeping bag. It features 600 fill hydrophobic down for better performance in rain and snow. A thermal hood and top draft collar means a better night’s sleep in bad weather. <a href= “https://www.rei.com/product/110922/rei-co-op-magma-10-sleeping-bag-mens?cm_mmc=aff_AL-_-145262-_-180150-_-NA&avad=180150_ef3e3f1d”>REI Co-op Magma 10 Sleeping Bag</a>Simply looking at a picture of this design REI speaks of warmth and comfort. With water-resistant 850-fill goose down and 15-denier lining to give a super-soft feel. A foot box with toe box baffles to keep extremities cosy warm while the insulated yoke stops warmth escaping between the neck and shoulders.Summing UpWhere weight is not a consideration, the rectangular sleeping bag is a good choice for car campers. The extra size gives good comfort especially for couples looking to share sleeping arrangements.Mummy style bags are the obvious choice for hikers venturing into the back country. The cut of mummy style bags hugs the contours of bodies making them more efficient. In general, mummy bags have short zippers as bag entry can be a weak point in keeping out drafts. Getting into this style of bag is a process of wriggling down to the bottom; a turn-off for anyone wanting a blanket style covering. Mummy style bags can cost twice as much as rectangular bags due to expensive down insulation and inclusions such as collars and hoods, making this style of bag the first choice when facing the vagaries and uncertainty of seasonal weather.