Temperature ratings

European standard EN13537

Since 2012 Helsport has used the European standard EN13537 to rate its sleeping bags. This standard allows comparisons amongst sleeping bags from different producers. The standard gives three temperature values: TCOMF, TLIM and TEXT. The temperature ranges between the values are zones for the recommended use. All sleeping bags on our website are marked like this:

Green zone above TCOMF: the green zone is called the “comfort zone”, and in this temperature range most people will be able to sleep comfortably.


Yellow zone between TCOMF and TLIM: the yellow zone is called a “transition zone”, between comfort and risk. Many people can sleep comfortably in this temperature range, but some may also start to freeze (see more info below).

Red zone between TLIM and TEXT: The red zone is the “risk zone” and, in this range, a strong sensation of cold has to be expected. There is a risk of hypothermia. An average-sized woman can only tolerate this zone for six hours.

The three temperature values are determined as follows:

  • T-COMF: Comfort temperature for a standard woman in a relaxed position.
  • T-LIM: Limit temperature for a standard man in a rolled-up position trying to stay warm
  • T-EXT: Risk temperature for a standard woman under cold stress in a rolled-up position, can only be maintained for six hours.

Limitations in the standard

For longer trips and expeditions an extra safety margin should always be applied. The user is responsible for testing the gear’s temperature limits prior to such trips. The temperature standard EN13537 does not apply to children’s sleeping bags. The temperature stated is only a reference to the corresponding adult size bag. Children have different physiological temperature regulation than adults.  Children should add an extra safety margin, and adults are responsible for keeping children in their group warm.

When to use the sleeping bag in real life?

It is important to know that the temperature rating is valid for an average person, in an average situation. When you are out hiking, no single trip is the same. People react differently to cold, levels of fitness can vary, and the surroundings will change every time. A fit, experienced hiker on an easy trip will not need as warm a sleeping bag as an inexperienced, first-time user on a strenuous adventure. Helsport therefore advises you to choose a sleeping bag after first considering two main aspects:


  • How easily do I normally get cold?
  • How experienced am I at sleeping outdoors?
  • How good is my current level of fitness?


  • What kind of trip am I going on?
  • How hungry and tired will I be when I’m going to sleep?
  • How well-protected will I be? (in a cabin, under the open sky, what kind of sleeping mattress, extra clothing etc.)
  • How much weight am I willing to carry?

After considering these questions, each user can choose when to use the sleeping bag: