Sleeping Bag Temperature Ratings: Which to choose?

Buying a sleeping bag can be a daunting task with all the various temperature ratings contained on the bags or in the support literature. There's the "Comfort Limit Rating", "Lower Limit Rating" and of course the "Extreme Limit Rating". So what do they all mean? and which should you be most concerned about.

Have a watch of the following video or read some of the pointers that backcountry.com has to offer. Then check out our sleeping bag review sections which are broken into two sub-sections, three season sleeping bags suitable for spring, summer and fall and four season bags suitable for ski touring adventures. If you are looking for a great deal on a new sleeping bag be sure to click on the links at the bottom of each review for the best prices around!

Prior to the widespread adoption of the EN testing standard for sleeping bags, manufacturers assigned temperature ratings to sleeping bags based on their own testing methods and standards—which included everything from sleeping in a meat locker to real-world testing experience. Because of the variation in different brands’ testing methods, which produced ratings ranging from conservative to inflated, these in-house ratings were at best a rough guide for picking the right sleeping bag, and they made it nearly impossible to reliably compare sleeping bags across brands.

Fortunately, nearly all major sleeping bag manufacturers have adopted the EN testing standard in recent years. Because these tests are conducted by a third party in internationally certified labs using standardized testing methods for each bag, the resulting ratings serve as a fairly accurate guide to what temperature range a sleeping bag is best suited to perform in. More importantly, this standardized testing allows you to reliably compare sleeping bags across different brands, helping you pick the perfect bag for your next excursion. When looking at EN temperature ratings, there are two main numbers you’ll want to look for and consider— the EN comfort rating and the EN lower limit rating. The bag’s comfort rating indicates the lowest temperature in which the average woman will sleep comfortably in that bag. The lower limit rating indicates the lowest temperature in which the average man will sleep comfortably in that bag.

In addition to the weather, there are a number of other factors to consider that will affect the temperature rating assigned to your sleeping bag. For instance, sleeping in a tent or bivy sack will add about 10 degrees of warmth to the rating assigned to the bag. The amount of clothing you wear will also affect how warm you will be. For reference, keep in mind that the heat-sensor mannequins used in the EN tests are clothed in one layer of long underwear and a hat. The insulating value of your sleeping pad can also increase how warm you will be. Many sleeping pads are assigned an R-value to indicate how well they will insulate you against the cold ground. In short, the higher the R-value, the better. When choosing a sleeping bag based on its temperature rating, it’s always best to air on the side of caution, especially if you’re a cold sleeper. Remember, it’s far easier to unzip your sleeping bag to reduce the amount of warmth than it is to try and increase the warmth by adding extra clothing or layers.

The Mont Bell Down Hugger 900 Sleeping Bag.

The Sierra Designs DriDown Cal 6 Sleeping Bag.