There are many different types of sleeping bags available on the market. Not only are there different shapes, but they also come with different forms of insulation and different weights.
There are many things to consider when looking for a sleeping bag:
– What temperatures do you expect to encounter?
– Are you a warm or cold sleeper?
– Do you need weatherproof materials?
– What shape will work best for you?
Sleeping bags are generally filled with either synthetic materials, down or a combination of both. Each fill type has its advantages. Synthetic materials are more resistant to heat loss when wet while down gives a better temperature rating for less weight and is highly compressible. Some companies now offer mixed synthetic/down bags to capture the best of both. If wet weather is a concern, down bags can be contained in dry bags. You can even put in your latest The PNW Ultralight Backpack.
Many new bag are also made with an outer waterproof shell to prevent soaking while the bag is in use. This can be a concern if condensation from the tent is an issue or if open sided shelters are used. Wet down is not a pleasant thing to deal with. Down tends to clump up and loses much of its insulative properties. This shouldn’t scare you away from down though as down is a great fill material. Synthetic on the other hand works wet or dry although a wet synthetic bag will still be unpleasant, it just will not have clumping issues. Synthetic doesn’t compress nearly as well as a comparable down bag and they also tend to be heavier. For those with down allergies, there are a few companies that are now carrying hypo-allergenic down bags.
Sleeping bag shapes and lengths are more varied then fill types. It is possible to get sleeping bags in a half length (also know as an ‘elephant’s foot’), a three quarter, a petite, kid sized, regular (generally fits up to a 6′ person), and long. The half and 3/4 length are best paired with a jacket and hood, or cap. Kid sized bags are scaled both in height and width and should be considered for kids over an adult bags as kids will have a hard time heating up the extra space in an adult bag. The petite bag is also a new addition on the market and is geared for women (or short men/big kids). A petite bag represents the opposite side of the sleeping bag spectrum from the long, it is smaller then a regular. Women’s bags generally have a slightly larger cut in the hip area, less width in the shoulder area and sometimes have additional insulation in the foot box and sometimes the chest area.
The old camping standard is the rectangular bag. It is basically a large square with a zipper down three sides allowing it to zip into a one person rectangle or to mate with another square to form a two person sleeping bag. Rectangular bags have seen a face lift with more modern materials, a trimmer shape and a hood. They are mostly still rectangular but they now have a zipper only down one side. While they offer more space for movement, that extra space can be harder to keep warm and may lead to a cooler night’s rest.
Mummy shaped bags have a more streamlined shape tapering in at the legs and feet. The cut is not very generous but with less interior space to warm up, it is easier to stay warm throughout a cold night. Mummy bags also tend to weigh less then their rectangular counterparts due to less materials. Quilts are similar to the mummy shape but don’t have a zipper or hood. They are open down the back. In order to use the bag, it is tucked under your shoulders to keep it wrapped around your body.
There is now a new category of sleeping bag, the best term I can think to describe this category is the ergonomic bag. This isn’t a totally new concept, there are now several bags on the market that allow for mobility while staying contained in your cocoon of warmth. The Selk sleeping bag body suit is the most conforming while the Exped Wallcreeper more resembles a large down vest that you can pull down and cinch below your feet.
Bags come in different weights ranging from summer weight, to expedition weight. Summer bags are best only for warm summer nights, generally rated from 50F and up. They can be combined with a heavier bag to extend the temperature of the heavier bag. Spring/fall bags are meant for cooler nights but can still be used over the summer with the zipper left down. The ratings for these bags falls between 35 and 45F. Winter bags, good for cold winter nights generally work over the 0 to 35F range. Expedition bags are rated for below 0F use. Most recreational backpackers can get away with a 35F bag.
Someone who chills easily when sleeping will require more insulation then someone who overheats easily. The best bag to buy that will work on most 3 season trips will be a bag that keeps you warm in the spring and fall with thermal underwear on, and can be draped over you in the summer to ward off a chill but still allowing for air flow. The bag should be light enough that you want to carry it without sacrificing on quality or warmth. While most people do not have a need for waterproof exteriors, it can come in handy to have some waterproof material on the hood and foot box to protect against tent condensation.
Any bag can be extended through the combined use of thermal underclothes and liners. The silk liner is great for keeping a sweaty, dusty body from dirtying up a bag. A fabric liner adds a few more degrees of warmth and fleece liners can add up to 10 degrees of additional warmth. Going to bed warm and even tossing in a water bottle full of hot water into a sleeping bag can help keep you warmer over a cold night.
Never under estimate the power of shared heat. The old Coleman style car camping sleeping bags could be mated together with one bag on the top and one on the bottom, it is still possible to mate two bags together, but today’s bags mate side by side. Each sleeper still stays mostly contained within their own bag but the bags are open to each other on one side. Most bags come with zippers either on the left side (which is ideal for right handed people) or zippers on the right side (ideal for left handed people). Numbering among the minority are center zip bags, and bags with no zipper (ideal for the gram pinchers).
There is no one perfect sleeping bag. Everyone is different and every bag caters to those differences.