Sleep like a baby in the backcountry.

There is nothing worse than a cold, cramped night’s sleep. Sleeping bags are another one of those gear items that quickly start multiplying as you expand the types of trips you take, when you take them and where you go. A lofty down bag is not the right choice for a spring backpacking trip in the Pacific Northwest just as a synthetic bag might not be the best choice for a quick alpine ascent. Being happy with your bag choice doesn’t stop with the bag either – there’s the pad and your own body temperature to consider as well.

That’s right, staying warm isn’t so much a factor of how much you spent on your sleeping bag, but how much your internal furnace is cranking and that piece of foam you’re sleeping on (you are using a sleeping pad right?). So, before we jump into how to choose what you sleep in and on, you should know the basics of staying warm outside.

A sleeping bag is like a cooler. You put hot in it, things stay hot. You put in cold, things stay cold. If you go to bed cold, that’s how you’ll stay. Have a good meal before bed, but don’t overeat. If you know it’s likely to be cold out, try to minimize down time between arriving in camp and getting in your sleeping bag. That means cook fast, and get in your sleeping bag to eat. Hydrate well because dehydration will cause you to decrease the efficiency of your body’s thermostat, but if you need to use the bathroom, do it. There’s nothing worse than a full bladder to keep you up and cold. And finally, don’t wear so many darned layers. “Layering” has become this new buzz word and I challenge you to go to REI and have a conversation with the sleeping bag rep without hearing the word. If you need 16 different layers to stay warm, you’ve got the wrong sleep system. Chances are, the more you layer, the more you’ll sweat, which will get you wet and downright miserable. A thin layer or nothing is key, but definitely wear a warm hat first if temperatures call for it. For some more tips on staying warm while camping, check out this article.

Here are the five things I’ve found most important in my quest for choosing the right sleep system:

1. Sleeping Pad

There’s nothing more key than this piece of gear. The ground is cold and you’re going to lose a lot more heat to it than to the air (conduction is a more efficient process than convection), especially if you’re sleeping in a tent. Sleeping pads are rated using something called an R-value and if you’re looking to buy something to use for every season, something around 3 is your best bet. My recommendation is the Therm-a-rest NeoAir (the NeoAir All-Season is a bit warmer and more expensive, same weight), for high warmth, low weight, and the feeling of being on memory foam. It’s pretty pricey, and you can definitely get something cheaper, but you’ll be carrying more weight and it’ll take up precious pack volume. Beware of down or synthetic insulation filled products, which are potentially good for winter use (but probably not), and just a gimmick for the beginner outdoor sports enthusiast.

2. Temperature Ratings

You probably don’t need a bag as warm as you think you do and in reality the temperature ratings on the bags are about as accurate as the 15-day weather forecast. On most bags, you’ll find EN (European Norm) Ratings with two important values, the T-Comfort which is the lowest temperature you’ll want to use the bag in if you’re the average woman, and T-Limit, the same for the average man. Whatever that means. For a basic three season bag, aim for the sex-specific bag you can find that matches either of those values around 32 degrees Fahrenheit or 0 degrees Celsius (and yes, women’s bags are in fact not just smaller men’s bags). You might have a sales person insist to get a little temperature padding, but that’s an old relic from the days when sleeping pads were about as insulating as your doormat, and if you followed my first two recommendations, you’ll be fine most of the time. At worst, you can add a thin layer to bump the heat and you’re goooood.

3. Bag Cut

You’ve got mummy vs. rectangular. Use the mummy cut because you’re backpacking and not going to a sleepover and the cut improves the warmth. If it’s warm enough you don’t need the mummy cut to boost the temperature of your sleep system, then you can just open the bag and drape it over you for more comfort. Look for a sleeping bag that has a zipper that allows you to vent the bags slightly at your feet. I find that this is one of the more crucial aspects of venting warm, moist air from your bag and preventing you and the fabric from becoming a soggy mess, thus making you even colder.

4. Down vs Synthetic

The age-old battle. Down insulation comes from a bird's plumage that lies under its feathers with the highest quality coming from Goose down. The fill power is the number of cubic inches displaced by one ounce of down. So, if a bag has a 650 fill power, it will be heavier and less compressible than a similar looking and equally warm bag with a higher fill power. No matter what a salesperson says, higher fill power down is NOT warmer than lower fill, just lighter per unit warmth. And don’t fall for the “Dry-treated” down gimmick – it might, maybe, potentially, perhaps retain a bit more insulative value in moist environments, but I guarantee you a good Pacific Northwest moist forest campsite will make you want synthetic.

At the risk of being burned at the stake, I’m going to recommend this heretically: just get a synthetic sleeping bag as your first one. The Mountain Hardwear Lamina Series is excellent but there are plenty of good options that are less expensive as well. Here are the advantages: you can go anywhere in the United States, anytime in the three seasons and you don’t have to worry about moist air ruining your down’s insulative properties. It’s more durable, and honestly, for entry level bags the weight difference isn’t dramatic. The big downside is that synthetic fill packs down over time and you can expect your bag to only be half as warm within a few years (like two). By then you’ll know what you want out of a bag and which environments you prefer backpacking in, you won’t need this review or the sales rep to pick a sleeping bag and you’ll have a free, pre-loved, car camping warm weather bag.

5. Testing and Storage

When you buy the bag, try sleeping in it while laying on your chosen sleeping pad. You’re looking for two things. The first is that the friction coefficient between the two items is sufficient enough to stay on the pad in the first place. If you zip off every time you move an inch, you’ll be pretty annoyed. The second thing you’re looking for is that your feet are not pushing on the foot box of the bag. This will make the insulation there collapse and your feet are going to get very cold. In doubt, go for a longer bag. Invest in a good stuff sack that will keep your bag reasonably dry, but never store your bag in that stuff sack! Remember that synthetic insulation packs down, don’t speed up the process.