Warmth You Can Trust: Considering all the variables that affect how warm you sleep, providing a single number for a sleeping bag rating can be misleading. That’s why we test all of our sleeping bags to the EN (European Norm) 13537 Standard. The following definitions will help you understand this Standard, and how to use it to find the bag that’s right for you.
Comfort Range: This is the temperature range where you can expect the bag to provide reliable warmth for a “standard” man or woman. Below this, the test’s “standard woman” will begin to feel cold.
Transition Range: In this temperature range, a “standard” man will be comfortable.
Risk Range: In this range, a strong sensation of cold has to be expected. There is risk of health damage by hypothermia. The bag should only be used in this range in an emergency, or by those with ample experience in augmenting a bag’s warmth.
Standard Woman: 25 years old, 132 lb (60 kg), 5’2” (157 cm)
Standard Man: 25 years old, 154 lb (70kg) and 5’7” (170 cm)