Perhaps the most beloved item in a hiker’s kit. After a long day on the trail is there anything better than crawling into a warm sleeping bag and drifting off to Mother Nature’s wonderous soundtrack? Intangibles aside, it is important to have a sleeping bag that meets both your own individual needs and the dictates of the environment into which you are venturing. Consider the following points:
Down Vs Synthetic
Generally speaking down bags have a better warmth to weight ratio, last longer and are more compressible than their synthetic equivalents. The primary negative associated with them is that they are useless when wet. This is true, however it rarely represents a concern as long as you take some basic precautions such as lining your backpack with a garbage bag.
The Ratings Game
Just because a company claims that “X” bag is rated to -10°celsius, doesn’t necessarily make it so. Traditionally such ratings tend to be a little on the high side of your average person’s reality (eg. A -10°celsius bag that leaves you shivering when the thermometer is reading 5° celsius). It is worth noting that generally speaking, women tend to sleep 5 to 10 degrees colder than men.
Warm or Cold Sleeper?
Everyone is different. Often a sleeping bag’s rating may be spot on for a warm sleeper, but may leave a cold sleeper wishing they had upgraded to a warmer bag. Before shelling out big bucks on an expensive sleeping bag, it pays to have an idea where you are situated on the scale of warm to cold sleepers. For example, if winter is approaching and you are still sleeping in shorts and t-shirt while everyone else around you has broken out the heavy-duty thermal underwear, chances are you are a warm sleeper.
Two For One
If most of your hiking is done with a spouse or partner, it may be a good idea to buy bags with compatible zippers. That is, one with a left hand zip and one with a right hand zip. The shared body heat will increase the warmth factor considerably. If you would like to take things a step further and save even more weight, you and your partner may consider investing in a 2 person quilt (see The Big Three in GOING LIGHT). However, before making such a purchase, take a moment to think. A double quilt may be fine for “cuddly” sleepers, but not so good for those who need their own space. Definitely steer clear of this option if your partner is a “blanket” hoarder.
Shape & Size
Most hikers go for mummy bags, which are wider at the top and taper in towards the bottom. However, if you are a restless sleeper who tends to move around a lot, you may consider buying a wider bag. You can’t put a price on a good night’s sleep. Note that roomy bags mean more airspace, which in turn translates to loss of warmth.
You Get What You Pay For
While most lightweight hiking gear is less expensive than its heavier equivalents, the opposite is true of sleeping bags (and all down products, for that matter). A good down sleeping bag is not cheap. One factor which provides a clue as to the bag’s quality is it’s fill power. Basically, a high fill power (eg. 800+) equates to better quality down, which means superior insulation and warmth to weight ratio. In real terms, upgrading from a down bag with 600 fill-power to one with 800 fill-power, both of which have the same temperature rating, can mean a weight saving of up to 300 grams (10.6 ounces). The catch? Bags with higher fill powers are more expensive.
Sleeping Bag Liner
They keep the inside of your sleeping bag cleaner and add up to 5 degrees of warmth. Personally I don’t carry one when I am hiking. I would rather utilize the extra weight to bring along a beanie and a warm thermal top that will keep me toasty inside my bag and be useful outside as well.
I always go for a full length zip as it gives you the option of using your bag as a quilt when temperatures are warmer. A draft tube along the length of the zipper helps to keep the cold out.
Hood & Neck Collar
A large amount of body heat is lost through our head. An insulated collar and a well-contoured hood make for a warmer sleep. Alternatively, a beanie and shirt wrapped around your neck should do the trick.
Keep in mind that a sleeping bag, no matter how warm its rating, will not be able to perform to its optimum level without adequate insulation from the ground. In cold weather, a sleeping mat is vital in preventing your body temperature from dropping due to conductive heat loss to the ground. See the Sleeping Mat section for more details.