Sleeping Bag Temperature Ratings Explained

Sleeping bags are an essential piece of gear for any camping or backpacking trip, as they provide warmth, comfort, and a sense of security during the night. However, with so many different sleeping bags on the market, it can be overwhelming to choose the right one. One important factor to consider when shopping for a sleeping bag is the rating system, which helps to determine the temperature range in which the bag is suitable for use. In this article, we’ll explore how sleeping bag ratings work, including how sleeping bags are tested and the two main rating systems: EN and ISO. We’ll also delve into the specifics of each rating system, including what each rating means for each standard.

How sleeping bag ratings work?

First, let’s take a look at how sleeping bags are tested. Sleeping bags are typically rated by temperature, with lower ratings indicating a warmer bag that is suitable for colder temperatures. However, determining the temperature rating of a sleeping bag is not as straightforward as it may seem.

In order to accurately test the warmth of a sleeping bag, a standardized testing protocol is used. This involves using a heated mannequin, or “thermal man,” which is dressed in long underwear and placed inside the sleeping bag. The temperature of the mannequin is monitored throughout the night, and the lowest temperature at which the mannequin remains comfortable is determined to be the temperature rating of the sleeping bag.

There are two main rating systems used to determine the temperature range of a sleeping bag: EN (European Norm) and ISO (International Organization for Standardization). Both systems use a standardized testing protocol, but they differ in the criteria used to determine the temperature rating.

The EN rating system, also known as the EN 13537 standard, was developed by the European Committee for Standardization (CEN) in 2002. It uses three temperature ratings: the lower limit, the comfort limit, and the extreme limit.

• The lower limit rating represents the temperature at which a standard man, who is cold-adapted, will be able to sleep comfortably in a relaxed position. This means that the man will not be excessively cold, but may still experience some mild discomfort due to the cold temperature.
• The comfort limit rating represents the temperature at which a standard woman, who is lightly clothed, will be able to sleep comfortably in a curled-up position. This means that the woman will be able to sleep comfortably without feeling too cold or too hot.
• The extreme limit rating represents the minimum temperature at which a standard man, who is cold-adapted, will be able to survive six hours without risk of death from hypothermia. This rating is not meant to be used as a guide for comfort, but rather as a measure of the sleeping bag’s ability to protect the user from extreme cold.

The ISO rating system, also known as the ISO 23537 standard, was developed by the International Organization for Standardization (ISO) in 2012. It uses two temperature ratings: the comfort limit and the lower limit.

• The comfort limit rating represents the temperature at which a standard woman, who is lightly clothed, will be able to sleep comfortably in a curled-up position. This means that the woman will be able to sleep comfortably without feeling too cold or too hot.
• The lower limit rating represents the temperature at which a standard man, who is cold-adapted, will be able to sleep comfortably in a relaxed position. This means that the man will not be excessively cold, but may still experience some mild discomfort due to the cold temperature.

It’s important to note that these ratings are based on the average person, and individual factors such as age, body type, and metabolism can affect how warm a person feels in a given sleeping bag. In addition, these ratings are based on the assumption that the person is using the sleeping bag in conjunction with a proper sleeping pad and is wearing appropriate clothing for the conditions.

In summary, sleeping bag ratings are used to help consumers choose a sleeping bag that is suitable for the temperatures in which they will be sleeping. The EN and ISO ratings systems use the standard man and standard woman methods to determine the lower limit of a sleeping bag’s temperature range.