Your sleeping bag is one of your most important accessories, so it is very important to get a model that fits your needs. However, decoding sleeping bag temperature ratings can be a bit tricky, so it can be hard to figure out what really fits your adventurer.
We want you to have the best equipment you can for your camping trip, so we’ve prepared this guide dedicated to explaining the unexpected details about the temperature ratings of sleeping bags.
Next, we will discuss what you need to know about the temperature rating systems of sleeping bags so that you can be better informed when you go shopping.
Sleeping bag groups according to temperature
Before looking at how sleeping bags are graded, it is important to understand the categories that are categorized by temperature ranges. In hot, summer-like conditions or at low altitudes, a summer bag (32 degrees Fahrenheit and above) can be a great way to save weight, space, and money. But remember. Places like the Utah Desert, for example, can still be quite cool at night – so as not to get too close to the line.
The heart of the 3-ear range is 20 to 32 degrees Fahrenheit (and above), which is usually warm enough for most summer and shoulder-season backpacks, especially in the high mountains where temperatures are lower than freezing during the summer months. Plus, a little too much heat is usually not a bad thing.
For winter camping and mountaineering (less than 20 degrees Fahrenheit), a real winter bag is required. The ideal temperature rating for winter weather adventurers depends on the conditions, but exploration bags can run up to -40 degrees Fahrenheit or less.
- Summer / low altitude sleeping bags: 32 F and above
- 3-season sleeping bags: 20 to 32 F
- Cold Weather / Winter Sleeping Bag: 20 ° F and below
EN and ISO temperature classification systems
When shopping for a sleeping bag you may have seen “EN” (European standard) or “ISO” (International Organization for Standardization) ratings. Both organizations have the same goal: to standardize the warmth grading system of sleeping bags. EN (formally referred to as EN 13537) was the previous method and is still used in many bags on the market, but in 2017 adopted ISO and introduced a new standard (ISO 23537).
That is, the ISO test is very similar to the EN method. That we can talk about them one by one. Both EN and ISO tests involve the use of a heated gem. Technically, EN gives four ratings, the most relevant being “EN Comfort” (the average temperature at which a normal girl can sleep comfortably throughout the night) and “EN lower limit” (the average air temperature at which a standard male can sleep eight hours without waking up). Is.
The low-reference rating is “EN Extreme”, a temperature that can last up to six hours without the risk of death from hypothermia for the average girl. But we do not want to be associated with that ranking. ISO Comfort and Lower Limit ratings are very similar, but we like to say that “Comfort” is for cold sleepers and “Limit” is for warm sleepers.
As far as standardization goes, many US-based sleeping bag manufacturers have adopted EN or newer ISO testing methods, which help ensure consistency and accuracy. For example, companies such as REI Co-op, The North Face, Marmot, and Mountain Hardwear all use EN or ISO systems at different levels, and Western Mountaineering, Big Agnes, and Feathered Friends (instead, they do not set their own temperature. Ratings ).
How to evaluate non-EN / ISO-rated bags
As mentioned above, many leading gear retailers do not use the EN or ISO system (we assume that grading is a time-consuming and time-consuming process, such as receiving an “organic” certification). In our experience, EN / ISO non-rated bags are like the Wild West: gear companies choose their rating in-house with balances on low external inspections and accuracy. Of course, these companies do not want unsatisfied customers, they do not want to freeze people at night, But non-EN / ISO ratings should be taken with a pinch of salt.
In our experience, we have seen significant differences between manufacturers and bags. It is important to evaluate non-EN / ISO-rated bags when making sleeping bag temperature ratings, so two high-end sleeping bag brands stand out in terms of the warmth of their EN / ISO non-rated bags: Feather Friends and Western Climb.
Both are widely used by serious backpackers, alpinists, and guides, and we find their ratings to be quite generous. How to protect yourself from the sleepy cold? First, give yourself a buffer to work with when buying an EN / ISO non-rated bag or any bag for it. That is the wise thing to do. In addition, reading reviews about a particular bag can be helpful.
Finally, you have the bottom filling power of any bag and can be filled with weight. This is not a complete science and there are important external design factors, This is not a complete science and there are important external design factors, but it should be useful to know the quality and size of the drop and compare it to an EN / ISO rated bag.
How Sleeping Bag Design Affects Heat
When making sleeping bag temperature ratings, how the sleeping bag design affects the heat is even more important. Accordingly, beyond the actual temperature rating of a sleeping bag, factors such as product shape, features, and age all play a part in how close it lives to expectations.
First, let’s discuss how a sleeping bag actually works. In fact, it works like a charm: when you put a warm object inside, the sleeping bag helps keep that object warm. And if there is extra air space inside a sleeping bag, our warm body needs more energy to heat that empty space. This means that you should do your best to find a bag that fits you and does not have tons of dead space. The style of a sleeping bag can affect its warmth.
For example, some thru-hikers opt for bed linen, which rejects the traditional mummy shape for a minimalist blanket-like design. Finally, the age of your sleeping bag greatly affects its warmth. My 10-year-old, 15-degree bag has lost a lot of its upstairs due to years of use and storage and maybe a good size from its actual size.
In this case, it often works closer than the 30-degree bag. This is unavoidable to some extent, but you can do your best to take care of your equipment and store it in the open instead of filling it up when not in use. Allowing it to breathe out of its luggage bag is healthier than keeping it compressed for longer.
Other tips for maximizing heat
The weather can be volatile, and after all the sleeping bag and weather research we have done, no matter how ready we think we are, sometimes we get caught in the safety of the mountains. Therefore, it is important to be able to pull tools out of your proverbial toolbox when your sleeping bag is not tricky. First, wearing the right layers can change the world.
When backpacking, bringing a thick base layer set, extra fur climbing socks, and a warm hat is nothing. In general, merino wool is the foremost insulator in the outdoors. It is warm, removes moisture, and does not smell like most synthetic fabrics. In addition, many backers bring a down jacket to hang around the camp after the climb.
Most of the time and especially if it’s cool, we wear our down jacket over our baselayers at night. If you have a full mummy bag, this is essentially double, but a good down jacket is never a bad thing to have around. At the very least, it can be used as your pillow. It is also important to understand how your sleeping bag works.
Before going out, check the hood and draft collars, and make sure you are well versed in pinching them down. If you do not zip the bag completely and lower the heat, the last thing you want to do is easily insert the cold air. There are several other things you can do to keep your sleeping bag warm. As mentioned above, a sleeping bag is like a heat sink: a sleeping bag keeps something warm inside and warms it.
Similarly, if you put a cold object inside, it can cool very well. Especially on a cold night or if we have a long, taxing day and it feels cold, we jump around the tent, sit down or do a few quick laps before entering our bag. Alternatively, you can boil water immediately before bed, fill a bottle, and put it in your sleeping bag.
Perhaps our most popular and fun advice: Eat some chocolate. Really. Calories were originally a measure of heat, and the more you eat a higher quality calorie before you go to bed, the more fuel your body needs and the warmer you sleep. It’s hard work but someone has to do it.
Final thoughts
At the heart of the problem with sleeping bags is the need to reduce the weight of every wallet and save money. Warm sleeping bags are heavy and expensive, not to mention bulky, so the temperature rating to choose from is always a strict calculation. That is, when choosing a bag, we look at the forecast and get the minimum desired temperature at night, then lower it by 10 degrees to be safe.
For example, in the Cascades and the Colorado Rockies in Washington State, two places where we often carry our luggage, it is normal for temperatures to drop at night. Accordingly, the REI Co-op Magma 15 bag and its 28 ° F EN comfort rating should be perfect. If the frequent temperature drop in the background drops unexpectedly, we should all be fine.
The extra 10 degrees do not make us feel too hot, and it is easy to remove the bag from the top or remove a layer. It is a situation that is easier to deal with than to shiver all night and feel cold and tired. Unfortunately, as with most types of outdoor equipment, there is no one-size-fits-all temperature rating.
If you plan to camp in the middle of summer in the lowlands or go desert, a real summer bag with a temperature rating of 30 to 50 degrees may suffice. If you plan to go out in the winter or climb any kind of winter weather or participate in a hike, there is no way to get a real winter sleeping bag. The temperature rating you need largely depends on the activity and conditions.
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