How to Choose a Sleeping Bag

How to Choose a Sleeping Bag

A sleeping bag is probably the most important piece of camping gear you will ever own. Sure, lightweight tents are more fancy and exciting, but really, the core of the camping experience comes down to your sleeping bag. And that means what bag you choose matters a lot. A good sleeping bag will be easy to pack down and carry, it will keep you warm and cozy, without overheating. But the wrong bag will leave you uncomfortable, shivering and cold in your tent. And there are a plethora of bags available, with a huge litany of features, materials, and ratings. It’s absolutely overwhelming. So we’ve created this guide to help simplify your process when shopping for a sleeping bag and narrow down the field to a bag that’s perfect for you.

Intended Use

The first and most important question to ask yourself before you buy any outdoor gear is: “What am I going to use this for, and what do I need it to do?” If you don’t answer that question first, you’re doing yourself a huge disservice. Camping gear is expensive and specialized. There’s no “Best” sleeping bag. Instead, there’s the best sleeping bag for you, which may be very different from the most expensive, or warmest bags.

So why are you buying a sleeping bag? Where do you want to camp, what are the average nighttime temperatures of where you’re planning to use the bag? And are you planning on hiking with the bag in your pack?

If you’ll primarily be driving to a campsite and then sleeping in your sleeping bag, its size and weight doesn’t matter so much, you won’t ever have to put it in your pack and carry it for miles. So warmth and affordability will be your priority. But, if you’re planning on long, overnight backpacking trips, you’ll want to find a bag that combines a smaller size, and lighter weight with the warmth you need. Once you’ve figured out what you’ll actually be using the bag for, you can narrow down your search based on these options.

Down vs. Synthetic

Sleeping bags keep you warm by trapping a layer of air around you that insulates you from the outside temperatures. They do this using two main materials, down, and synthetic insulation.

Down insulation is usually more expensive than synthetic insulations because it’s got a greater warmth to weight ratio - it will keep you warmer while weighing less. That said, down has its weaknesses, it’s much more prone to wetting out and losing its warmth than synthetic insulators.

If weight is a priority, go down, and just make sure to keep it dry. But if you don’t mind gaining a few grams, a synthetic bag can save you a lot of money, and is easier to care for down the road.

Temperature Rating

Temperature Rating

Almost all sleeping bags come with some sort of temperature rating system, but it’s important to know how to use this system to find a bag that will work well for you. Look for bags with a rating system that says either “EN” or “ISO.” Those acronyms mean the rating system is standardized among manufacturers, so one brand’s 30 degree bag has the same amount of insulating power as another’s.

Beyond that though, there are several calculations that should go into choosing the warmth of your bag. The rating system has two numbers: a “comfort” temperature, and a “limit” temperature.

If the bag has only one temperature rating, check whether it’s a unisex, men’s, or women’s bag. Men’s bags with only one number are generally the “limit” number, as are unisex bags. Whereas, women’s bags generally reflect the “comfort” temperature.

Knowing what those temperatures mean is key. The “comfort” temperature is the outside low temperature in which an average person will stay comfortable. The “low” temperature is the outside low temperature at which an average person will be able to sleep, with some discomfort. Obviously, those numbers are rather arbitrary, so think about your own habits, do you sleep warm, or cold?

Look for a bag whose “comfort” temperature rating roughly matches the average nighttime lows in the areas you want to camp. It’s ok to get a bag that’s a little warm, it’s easy to unzip and cool off. But it’s much harder to make a bag warmer.

However, if you’re looking to extend the use-range of your bag, it’s easy to get a silk liner that ups the temperature rating of the bag by about ten degrees. This allows you to use a lighter bag in the summer, and up the warmth in the spring and fall.


Once you’ve figured out the materials and temperature rating you want, it’s time to pick what shape bag you’re looking for. The three main shapes are: Mummy, Rectangular, and Tandem. Mummy bags are the lightest, and pack down the smallest, because they use less material, and instead hug your body shape. These are best for folks looking for the lightest bags. The downside is that they can be uncomfortable and restrictive, especially for side sleepers.

Rectangular bags don’t pack down as small, but feel more like sleeping in a traditional bed, with sheets above and below you. They don’t pack down as small, and weigh more, but they’re the most comfortable option for car campers, and many can be unzipped to create a comforter for warmer nights.

Finally, tandem bags are designed for two people. This allows you to share body warmth, and other things. Tandem bags are great for couples, but aren’t efficient to hike with, since one person has to carry one big bag, instead of two people carrying smaller bags. Some mummy bags can also zip together to form tandem bags as well.



If you’re pretty average sized, you don’t need to worry too much about sleeping bag sizing, but it matters a lot if you’re very tall, usually above 6’. If your bag is too short, you’re going to have a cold chest and shoulders. Many bag makers sell “long” sized bags for people over six feet. They weigh a little more than average bags, but make a huge difference for taller campers.

Other Features

Finally, it’s important to remember that your sleeping bag is part of a sleep system. It needs to work together with your sleeping pad to keep you warm. If you don’t move around too much while sleeping, some bags, like those from Big Agnes, come with an integrated sleeve for the sleeping pad, which helps protect it and keep you warmer.

In addition, if you think you might be cowboy camping, without a tent, it’s a good idea to look for a bag with a DWR coating to help protect it from dew.

Finally, some bags are specifically made to work in tandem with a puffy jacket, they have heavier insulation around the legs, and lighter, or no insulation around the torso. That allows them to pack down smaller and still keep you warm. However, this style of bag is only necessary if you’re willing to trade comfort for weight.

So before you go out and buy a new sleeping bag, ask yourself what you want to do with it, and what you need it to do. Then use this guide to narrow down your options.

About the author


Hey there, I'm Lisa, founder and editor in chief here at Recreation Space. We found fitness through recreational activities. And we want to share it with you. We believe in empowering people with knowledge to make smarter, healthier choices in their lives.

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