Sleeping Bag - Temperature Ratings

Temperature Ratings

In Europe, the EN 13537 standard normalizes the temperatures at which a sleeping bag can be used. A test, relying on a heated mannequin, provides four temperatures:

• the upper limit is the highest temperature at which a 'standard' adult man is able to have a comfortable night's sleep without excess sweating.
• the comfort rating is based on a 'standard' adult woman having a comfortable night's sleep.
• the lower limit is based on the lowest temperature at which a 'standard' adult man is deemed to be able to have a comfortable night's sleep.
• the extreme rating is a survival only rating for a 'standard' adult man. This is an extreme survival rating only and it is not advisable to rely on this rating for general use.

The transition zone, in between the comfort and lower temperature, is usually considered as the best purchase guideline.

In the U.S., a sleeping bag's rating typically indicates the lowest temperature at which it will keep the average sleeper warm. For example, with a 0° bag, you should be able to sleep comfortably in 0° temperature.

There is no standard measurement rating in the U.S., so a 20° bag from one company may not provide the same warmth as a 20° from another company. And there are other variables to consider, such as what you plan to wear when you sleep, what type of sleeping pad you use, and how well you hold the heat in your bag.