Sleeping bags are a tough topic to cover because of user preference. Some people are side sleepers (like me). Some people get cold faster, others run hot. Some only camp in the summer and others camp all year round. Some people car camp, and others backpack. Because of these personal aspects, the right sleeping bag will not be the same for everyone. To complicate things further there are different styles of bags that confuse people. Also, I want you to think of sleeping bags in conjunction with your sleeping mat. They work as a team and results can vary significantly with the parings you choose. For that matter your tent can also have an impact but that’s not the scope of this write up.
Things to consider when selecting a sleeping bag
- Am I a person that is usually hot or cold?
- What temperature conditions will I be camping under?
- Am I very tall or very short?
- What Style is right for me?
- What is my budget?
- Am I primarily a car camper or backpacker?
- What are the tradeoffs between materials and how do they impact cost?
- What warranties does the seller or manufacturer provide?
Sleeping Bag Temperature Ratings
When deciding on the temperature rating of your bag think of the following two things. What conditions will you typically be sleeping in and are you generally a person that runs cold, hot, or just the average. Most sleeping bags are rated with a comfort rating and a lower limit rating. Those bags with an EN tag on them are using a European Standard that a lot of companies use. For more on the criteria, and the methodology used, you can go to this Wikipedia page on it: https://en.wikipedia.org/wiki/EN_13537
The relevance of this is that it gives you a guideline on how the bag will perform and you can compare bags across manufacturers. However, not all claimed limits you will see will have gone through this certification so if the certification is absent, you are trusting the company’s claims (which may or may not be true). So how should you interpret this comfort limit and lower limit? I would say that those that run cold should adhere to the comfort limit. Don’t go below it. Those that run hot can get away with the lower limit. Just check what the nighttime lows will be during most of your trips and choose a bag that matches that temperature rating.
Boosting the rating of your bag and temperature adjustments
Let’s say for instance that you have a sleeping bag that has a lower limit of 40 degrees Fahrenheit but you are planning on sleeping in 30 degree weather. One way to boost your bags performance is to get a bag liner. My silk liner for instance claims to add 10 degrees to the bag. Some people also use liners just to keep their bags clean. It’s a lot easier to clean a liner than a bag. The other thing that you can do which is probably the simplest, it to wear more clothing. Sleep with your jacket, long johns, socks, and some sort of head cover. A little trick you can employ is to boil some water and put that in a water bottle and sleep with it. Another very important factor for sleeping in toasty warm comfort is your sleeping mat. The higher the R-factor, (a measurement of thermal resistance) the warmer you’ll be. Changing out your mat for a higher R-factor mat will reduce your heat loss and therefore keep you warmer.
If you find yourself sweating in your bag, open the zipper at night and consider just using it as a blanket with the zipper open facing downward. Take off your clothes if necessary. If all that fails and you are on ground that is not rocky. Don’t sleep on your mat (assuming you have one). One of the biggest thermal losses comes from contact from the ground so if you are hot, use the ground to suck that heat away.
Another tactic for you hot sleepers that want a little extra room in your bag is to get a larger bag than you need. Since there will be excess air volume in the bag, the heat you produce will have more space to spread out, and that will keep you cooler. However, a word of caution, this could also produce inconsistent pockets of temperature. For instance, you might be fine at your core, but your feet may be colder than you would like.
There are short, regular, and long bags. Each manufacturer has sizing charts that vary so you are going to have to look at these to see what size is appropriate for you. However, most people will fall in the regular category. I am 6’1″ and am at the cusp of many regular bags. Since I sleep a little scrunched up, I can generally fit in regular bags. If you sleep flat on your back or stomach, and are in excess of 6’1″, you are likely going to need a long bag. Shorter people should go for a short bag if available from the manufacturer or consider a kids bag. There is no reason to carry the extra weight. Also having a bag that is too large for you will make you colder. As mentioned earlier your body heat has to fill that excess volume of air so by having this extra volume, your body would have to produce more heat to keep you comfortable.
Mummies – Your standard hooded sleeping bags. These are best for back sleepers and those seeking maximum heat to weight ratio. They can be uncomfortable for side sleepers and those that like a range of motion when they sleep. This style is the more traditional and is the preferred type of bag for winter camping. Some people feel a little claustrophobic in these bags.
Quilts/Blankets – These are best used for 3 season camping (Spring, Summer, and Fall). They are generally lighter since they lack a hood and there is less material. They are best for those that like a full range of movement in their sleep. People that sleep cold may find some of these to not be warm enough. These are not recommended for cold weather camping.
Rectangular bags – It’s a compromise between a mummy bag and quilt. They keep more heat in than quilts since they are closed off. They also give you more of a range of motion than a mummy but, are not as thermally efficient as a mummy bag. Many of these lack a hood.
Bed systems – This is one of the newer kids on the block and a style that I am very intrigued by. I really want to try one. These have a pocket you slide into and then a quilt on top. It looks to be the most comfortable sleeping system but for this comfort, you are going to pay for it in weight. Since I am geeking out about this bed, I am going to include a video by Sierra Designs explaining its features.
If you are budget constrained, you should elect for a synthetic bag. You should also elect for a synthetic bag if you are a car camper. There is no reason to spend the extra money on a down bag. When comparing equivalent temperature ratings of synthetic and Down bags, synthetic bags are going to be cheaper. If you have a nice size budget and are backpacking, I recommend a down bag. I started with synthetics because of my own budgetary constraints but I now cannot imagine not having my down bag. I’ll explain a little more about why that is a little further down.
Tradeoffs between Materials, Weight, Performance, Compression, and Price
When we hike we don’t want to be burdened with extra weight or extra volume. For equivalent temperature ratings between synthetic and down bags, synthetic bags are going to be heavier and are going to compress less compared to their feathered counterparts. The tradeoff for a performance boost is price. If you go the feathered route, you will be paying more. However, I strongly feel you will get more out of your purchase. Your bag will be lighter and will compress more. It is true that synthetics bags dry faster and handle moisture better overall. They also retain more of their insulation properties when wet. Down clumps up and can be useless when fully wet. However, with the advent of hydrophobic down (down treated with water repellency), the moisture handling, and thermal properties when exposed to moisture are better now. You still can’t dunk you hydrophobic bag in water and expect it to perform, but these repellency features mean that they will perform better than the down bags of just a few years back. If you are a backpacker that can afford a down bag, get one. If you are a car camper, skip it and get yourself a synthetic. Your bank account will thank you for it.
My sleeping bag and how I use it
I personally walk around with a 4 season Sierra Designs mobile mummy 800 hydrophobic down bag. This is a mummy bag filled with hydrophobic down by DriDown. This is my second Sierra Designs bag after my first ripped due to no fault of my own. The company did what a great company should do. They stood behind their product and replaced my bag with the one I am currently using. I have to say the support I got from them was superb. For me, they approached Patagonia’s level of service.
One of the features I love about this bag are the arm holes. Granted this drops the bags temperature rating some, but the feature is phenomenal. Need to drink water at night, no problem. You don’t have to unzip you bag, you just pop your arm out. What to grab your phone to see what time it is, convenient arm holes give you that option. I look at it this way, the heat you lose through these slits is compensated by the heat you retain by not needing to open your zipper.
Here is another insane feature that I have not used other than to test it. The zipper on the bag is a double zipper. Meaning you can unzip from the bottom as well. You can open the bottom zipper and pop your feet out. Then you can fold the bottom of the bag behind you and affix it with two tabs on either side. What this allows you to do in the winter is wear it as a garment. Your arms are through those arm slits, and your feet are exposed, so you can put on your boots and exit the tent with your bag on. This is a top notch feature that is really useful when you want to go outside in the winter but don’t want to leave your toasty sleeping bag. In an effort for full disclosure, I have not used it in this capacity yet but am very excited to do so during my next winter camping experience.