So you’re packing for your next adventure and it’s time to grab a sleeping bag. How do you decide which bag to take? Enter the handy dandy but oh-so-confusing EN* rating, adopted by virtually all major sleeping bag manufacturers beginning in 2005.
The ratings are given after 3rd party labs conduct rigorous, standardized tests before arriving at a temperature range for the “average” person. Bear in mind that these ranges assume the use of a hat, gloves, base layer, and basic foam sleeping pad. Gender specific** bags assume that men sleep warmer than women, so bear that in mind if you’re buying The high end is the comfort rating. This means that the average person will be comfortable in the bag at the given temperature, snoozing away into the night. The mid-range of these temps will likely find the average person shivering, at least for a while, before they generate enough heat to stay comfortable through the night. The low end is the danger zone. In these temps, the bag may prevent you from death or very serious complications but you may suffer from frostbite or hypothermia. It should go without saying that you should not plan on taking your bag into these conditions--this is more of an “in an emergency situation you (probably) won’t die if you have this bag” rating.
All of that said, remember that this is based on averages. You may run hotter or cooler than the average person, and that will in turn affect your comfort and safety on the trail. I like to play it safe by selecting a warmer bag, especially for longer, colder adventures where weight isn’t a consideration. It’s easy to unzip or delayer if I’m too hot, but I can’t add layers or warmth that I didn’t bring with me and cold camping hacks like the trusty Nalgene full of boiled water and eating carbs before bed will only get you so far.
Things to consider:
The warmer and lighter the bag, the more expensive it’s likely to be. Choose wisely, and check to see if you can rent a bag to test it out before you buy. It’s also worth checking your local used gear store for a returned or consigned item. One good launder and it’s basically new!
Sleeping bag liners: though some question their efficacy, I have used a fleece liner to great effect on colder nights! Bonus points: they keep the inside of your bag cleaner and are very easy to wash.
Backcountry pajamas: the clothes you’re sleeping in matter. Where possible, have a clean, dry set of pajamas (socks, base layer, hat, midlayer for extra warmth, down booties, etc.) that are reserved for sleeping only.
Questions, comments, concerns? Let me know!
*This system was updated in 2017 to include an ISO rating and technically it’s the EN/ISO rating but that’s a long name that I don’t want to type twenty thousand times.
**I know, I know. WHY!