Criterion Sleeping Bag Temperature Ratings

The level of warmth you may feel in your sleeping bag is very personal and subjective. Some people are warm sleepers others cold, the r-value of your sleeping mat, the size of your tent and your use of a liner also affect warmth; as do a myriad of other factors. This therefore makes the job of assigning a temperature rating to a sleeping bag important, if a little perilous! As such you should only use a sleeping bag temperature rating as a guide. We recommend that you always err on the side of caution when purchasing a sleeping bag.

Some manufacturers offer three or even four temperature ratings which can be confusing to the uninitiated. At Criterion we have tried to keep our temperature ratings as simple as possible. We offer a single comfort temperature, which is the temperature limit we feel will allow the most comfortable night’s sleep. For our unisex bags (Quantums, Ultralights, Travellers, Primes and Expeditions) this temperature figure is based on the average male sleeping in average humidity conditions inside a typically-sized 1 to 3 person tent.  Therefore female sleepers using these bags should add 2 or 3 degrees to this rating. For our Lady range of bags the temperature rating given is for the average female in a 1 to 3 person tent in average humidity conditions.

Obtaining a Temperature Rating

To get to our stated temperature ratings our sleeping bags have been tested, to British Standard BS 4745 and ISO 5087-1, by the University of Leeds’ Performance Clothing Research Group. These tests gave both a TOG rating which you would be familiar with when buying a duvet as well as a specific temperature in °C. This is a starting point as laboratory tests are controlled environments, manikins do not move or sweat. Through product testing, expeditions and feedback we have refined the labratory ratings to the ones advertised for our sleeping bags. In cases where we have changed the tested rating, we have reduced the temperature to be more cautionary and safer.