Selecting the best lightweight sleeping bag for your adventures depends on many different considerations. Will you only be backpacking Spring through Fall or will you be out frolicking with polar bears? Are you a weekend warrior or will you be thru-hiking the Pacific Crest Trail for five months? These are all important factors that will influence the decision on the best sleeping bag for you.
When Will You Be Backpacking?
This question helps to determine what temperature rating you will need for your sleeping bag. If you plan to only be out when the weather is favorable then you’ll need a three season sleeping bag. On the other hand if you plan to be backpacking in winter conditions (temperatures below 15° with snow and/or ice present) then you’ll need a cold weather, or winter bag.
Every person is different and your comfort level can vary from the temperature ratings provided by manufacturers. This was a bigger problem in previous years as there was no real industry standard based on independant third party testing. This changed in 2009 when large US retail stores and select manufacturers moved to the European Norm (EN) standard. Be sure that any lightweight sleeping bag you are considering has EN ratings listed. Otherwise the temperature rating is really just an educated guesstimate.
The following temperature ratings are generally accepted guidelines:
Season Temperature Rating (°F)
Summer months 30° and higher
Spring, Summer, Fall 10° to 30°
Winter -10° to 10°
Extreme -10° and lower
As a general rule of thumb select a rating that’s less than the lowest overnight temperatures you will be camping in. If you anticipate sleeping in temperatures near freezing than a good choice would be to select a 20 degree bag.
It’s also important to realize that the temperature ratings assume that the person will be sleeping with a thermal layer (long underwear) and using a sleeping pad under the sleeping bag. See the Other Considerations section below for additional information on factors that influence relative warmth while sleeping.
How Long Will Your Adventures Last?
This question helps to determine the complicated tradeoffs of price, weight and volume of your lightweight sleeping bag. If you can only escape for weekend outings then generally speaking you can be more relaxed with the weight and volume considerations. On the other hand, if you will be backpacking for an extended number of days without resupplying then you will need to select the lightest and smallest bag you can afford. Thru-hikers considering the Appalachian Trail or the Pacific Crest Trail would fall into this latter category.
As a general rule of thumb for extended expeditions you will need to dedicate more weight and volume in your pack for food, fuel, additional clothing, and possibly additional gear as well. The reason why is that is that you have to be completely self-sufficient during that extended time. You cannot replenish your supplies when you are in the middle of the wilderness and 30 miles from the nearest town.
Consequently you will need to reduce the weight of your core equipment as much as possible. Lightweight backpackers find the biggest bang for their buck in terms of weight reduction by focusing on four critical pieces of gear: backpack, tent, sleeping bag, and sleeping pad. Obviously, the focus on this site is on selecting the best lightweight sleeping bag for your needs.
Volume (how much space something takes up) is another important consideration. Packs are rated in terms of liter volume capacities, as are most lightweight sleeping bags. All things considered it’s better to select the sleeping bag that takes up as little space as possible in your pack. Obviously the less space your bag takes up gives you more room for food, fuel, clothing and equipment.
Your sleeping bag is always something you want stored inside the backpack to keep dry during wet conditions. This will be discussed in the next section.
What Moisture Conditions Will You Be Facing?
This question helps determine the type of materials your lightweight sleeping bag will need to be built with. Do you plan on spending most of your time in arid environments where finding water is always the primary concern? Or will you be exploring places where it rains every day and humidity is a constant companion?
There are two basic types of insulation used in sleeping bags today. The first kind of insulation is down which is composed of tiny feathers harvested from either duck or geese. Down is rated by fill power which is important to understand. The second type of insulation is synthetic which are man-made materials. Both materials work well to keep someone warm at night by trapping the warmth of their body inside the bag.
There are costs and benefits associated with both types of insulation. The advantage of down is it takes up less weight and can be compressed down to a very small size compared to synthetics. The disadvantage to down is that it losses the ability to retain heat when wet. This might not seem like a big deal at first but stop to consider that it takes days for down to dry under normal conditions. If your down sleeping bag gets wet you’ll have to brave nighttime temperatures using only your clothing and any other equipment you have available.
The down moisture disadvantage may make it seem like synthetics are the only way to go. However, that isn’t necessarily the case for most people. The advantage of synthetics are that they retain their warming properties even when wet. However, there are a few downsides. First, synthetic sleeping bags take up more space in your backpack and also weigh more than their down counterparts. In addition, synthetic bags lose a little bit of their warming properties each time they are compressed into a stuff sack. Over time a synthetic bags effective temperature rating decreases in strength.
As a general rule of thumb it’s best to go with a down lightweight sleeping bag over a synthetic bag due to the lower weight and volumes. You should consider synthetic bags over down in the following circumstances:
- You camp with youth. They are prone to accidents, spills, and other mishaps involving liquids. Be sure to check out the article on the proper way to wash a down sleeping bag.
- You camp in very wet conditions. This can either be locations where rain is frequent, where you may be fording high rivers, or where conditions are very humid
If you often camp in the snow moisture can also be a problem. If you choose a down bag it’s important to remember to vent your tent to prevent condensation build up. Also under no circumstances should you put your head inside your sleeping bag at night. We exhale up to a liter’s worth of water at night. That moisture will go right into your sleeping bag. Most bags are breathable but are meant to deal with typical body sweat not exhaling all night long.
There is a new development in down bags worth mentioning. The down is coated with a microscopic water repellant chemical. The most common name for this treated down is DriDown. It’s important to realize that this makes down water resistant and able to dry in a quicker manner. It does not make down water proof just better resistant to liquids. It would be wise to choose DriDown if you have the option available when considering two similar bags. The price differential could literally mean the difference between an enjoyable night or one that is miserable.
Other Sleeping Bag Considerations
Shape – Nearly every lightweight sleeping bag has a mummy cut to its shape. This means that the bag is larger in the shoulders and tapers smaller towards the feet. Some bags may have a larger footbox which means there is more room in the location where your feet go. In addition, some bags advertise that they are wider in the shoulder area to accommodate those who like the roomy feeling. Keep in mind though that extra space equals dead space which means that you will be a little less warm.
Pad Loops – These are small straps on the bag that can be used to secure your sleeping bag to the sleeping pad below. People who are active sleepers (move around a lot at night) may find themselves laying on the cold ground because they’ve wandered off the sleeping bad. Pad Loops help prevent this from happening.
Hood – A majority of lightweight sleeping bags have a hood as part of their construction. It looks like a partial hoodie at the top of your bag and helps to retain the head that escapes from your head. The bag will have a cinch cord that allows you to close the hood around your face that only exposes your nose and mouth to the outside air. During summer nights this would cause you to boil in your sleeping bag, but in freezing conditions the hood will be your new best friend.
Draft Tube – This is an insulated tube of material alongside the zipper of your sleeping bag. The purpose is to prevent heat from escaping from the bag out the zipper and to prevent drafts from coming into the bag as well.
Draft Collar – This is an insulated tube found in cold weather bags that’s located in the hood. It forms a baffle to help prevent heat from escaping out the hood opening.
Stash Pockets – These are pockets sewn inside the sleeping bag used to store things like batteries, eyeglasses, knife, or keys. If you tend to sleep on your stomach then you’ll find contents in the stack pockets will end up poke you during the evening.
Stuff Sacks – Most of the stuff sacks provided by manufacturers are frankly lame. Once you buy your sleeping bag check out the stuff sack to see you can possibly salvage it. If not (which is typical) simply do some research to see which sack will best meet your needs.
Compression Sacks – These bags are similar to stuff sacks with one big difference… compression sacks have straps that allow you to squeeze the sack into a very small shape. If you are a thru-hiker or someone who needs to maximize pack space definitely check these out.