How to choose sleeping bags

It’s important to understand that a sleeping bag does not warm you up – its job is to retain the heat that your body generates, preventing you from getting cold. The below ratings describe how well a sleeping bag retains heat when the air exterior to the bag is at a certain temperature.

Because all of our bodies are different, what one person needs for a good night’s sleep is not necessarily the same as the next. This means that it is difficult to quantify exactly how warm a sleeping bag is and as such, any rating should be treated as a guide. This information from Rab, helps explain this in more simple terms and for this Rab relate to the European EN13537 standard to rate the majority of their sleeping bags.

For the EN13537 tested sleeping bags we list the three lowest temperature ratings; comfort, limit and extreme as well as the Rab Sleep limit.

Comfort rating

This rating expresses the optimal temperature you’ll experience when wrapped inside your sleeping bag.  You should use the Comfort rating as the basis for your purchase.

 Lower Limit Rating

The ‘Lower limit’ measurement is the temperature at which the test’s ‘standard male’ can remain asleep for eight hours without waking due to heat loss.

Extreme rating

The extreme rating expresses the absolute limit of a sleeping bag. It should be used to guide how a bag would perform in an emergency situation rather than a recommended use case.  It refers to the temperature at which a ‘standard female’ can remain for six hours without risk of death from hypothermia.

Sleep Limit

We also refer to the ‘Rab Sleep Limit’ to supplement the standard EN13537 results.  It is not an ’emergency’ metric in the same way as the ‘Extreme Rating’ rather what we believe the bag’s usable limit to be.

The Rab sleep limit is what Rab believe the sensible limit of the bag to be from past experience and feedback from their athletes and customers.

If you are going away on an expedition with Adventure Peaks or on your own trip, please phone the shop on 015394 33794 and option 3 if you wish for our advice on choosing the correct bag beforen you make your purchase.