By Michael Lanza
Finding a sleeping bag that’s right for you may be the most confusing gear-buying task. Getting the right one is critical to sleeping comfortably in the backcountry—and in an emergency, your bag could save your life. But with the myriad choices out there, how do you tell them apart, beyond temperature rating and price? This article will explain how to evaluate the key differences between bags to make your choice much more simple.
I’ve slept in many, many bags of all types over more than a quarter-century of testing gear—formerly as the lead gear reviewer for Backpacker magazine for about 10 years and even longer for this blog. I’ve zipped inside bags in all seasons, in temperatures from ridiculously warm to -30° F. (Ridiculously warm is more tolerable.)
In this article, I’ll share what I’ve learned about picking out a sleeping bag—or more than one bag—that will be ideal for your body and your adventures.
I’d love to read what you think of my tips or any of your own. Please share them in the comments section at the bottom of this story. I try to respond to all comments. Click on any bag photo below to read its review.
Table of Contents
General Tips For Buying a Sleeping Bag
• Know your own body. Do you get cold easily or are you a furnace? Women tend to get cold more easily, and this is a simple function of physics: Women often have a higher ratio of body surface area to mass compared to men, so their bodies lose heat more readily. Those women are more comfortable in a bag made for women, which is shaped differently than a men’s bag and typically has extra insulation in areas like the feet. However, it also comes down to body metabolism.
• If you get cold easily, get a bag rated 20 to 25 degrees colder than the coldest temperatures you plan to sleep outside in.
• People who don’t get cold easily will be more comfortable in a bag rated to within five to 15 degrees of the coldest temperatures you plan to sleep outside in—and possibly even a bag rated right around the coldest temp you’ll encounter, provided you have extra clothing to put on, just in case. (I’ve spent many nights around freezing perfectly warm enough in a bags rated 30-32° F.) Being too hot is not really any more comfortable than being too cold, and having a bag much warmer than needed means you’re carrying superfluous weight and bulk. (See “A Practical Guide to Lightweight and Ultralight Backpacking.”)
See “10 Pro Tips for Staying Warm in a Sleeping Bag.”
Down Vs. Synthetic Bags
Down has traditionally been lighter, more packable, and warmer than many synthetic insulations; but once wet, synthetics still kept you fairly warm, while down feathers become all but useless at retaining heat. Today, the lines between down and synthetic have been blurred somewhat with the development of high-quality, lightweight and compact synthetic insulations like PrimaLoft, and water-resistant down, which retains its ability to trap heat even when wet.
Down is more packable and very durable, so it still holds an advantage as the insulation of choice if you don’t expect to get that bag wet; and water-resistant down enhances your bag’s performance in common circumstances where it may get damp, such as when condensation builds up inside a tent. Still, even water-resistant down, once saturated, loses much of its ability to keep you warm, and drying out any bag is extremely difficult, if not impossible, in prolonged, wet weather. Synthetic insulation remains the best choice for extended trips in wet environments.
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High-quality down (rated from 800- to 900-fill or higher) is the warmest, lightest, most packable insulation out there, but expensive, while lower-quality down (usually 600- to 700-fill) still has the advantages of down and makes a bag less expensive but also heavier and bulkier. Manufacturers use lower-grade synthetic insulation in bags priced cheaply, making them much heavier and bulkier than better synthetic and down bags—typically too heavy and bulky for backpacking (unless you’re on a very limited budget and don’t mind carrying a big pack).
So the down vs. synthetic choice still comes down to pocketbook issues and the likelihood of your bag actually getting wet.
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In the past, bag manufacturers decided on temperature ratings for their own bags; the outdoor industry lacked a standardized method for measuring that. In recent years, though, the industry widely adopted the EN (European Norm) temperature rating system, internationally considered the most reliable and objective standard.
Found on most new bags, the EN rating typically includes three temperature ratings:
• Comfort rating, or the lowest temperature at which the bag will keep the average woman warm (based on the premise that women usually get cold more easily than men).
• Lower-limit rating, or the lowest temperature at which the bag will keep the average man warm.
• Extreme rating, or the lowest temperature at which the bag will keep someone alive, albeit not comfortable, in unexpected, extreme conditions.
Get the right tent for you. See “The 9 (Very) Best Backpacking Tents”
and “5 Tips For Buying a Backpacking Tent.”
See all of my reviews of sleeping bags and air mattresses and sleeping pads that I like at The Big Outside.
See also my related stories:
5 Expert Tips For Buying the Right Backpacking Pack
10 Tips For Spending Less on Hiking and Backpacking Gear
5 Expert Tips For Buying a Backpacking Tent
A Practical Guide to Lightweight and Ultralight Backpacking
5 Smart Steps to Lighten Your Backpacking Gear