Three things affect how warm you will be in a particular sleeping bag.
•   First is the environment: is it cold outside; what are you using for shelter; is there a breeze; what are you sleeping on?
•   Second is you: are you a hot or cold sleeper; is your metabolism fast or slow; do you sleep in the buff, rugged up or somewhere in-between; when did you last eat and drink? (And if you’re a woman, you will feel the cold more than a man: it’s not just a gender stereotype, it’s a fact.)
•   Both you and your environment make a huge difference to how warm you will be, and we can't control either of these things. The third factor is your sleeping bag.
All One Planet sleeping bags are temperature rated in accordance with EN 13537.
What is EN 13537?
‘EN 13537: 2002 Requirements for Sleeping Bags’ is the official European standard for the labelling of sleeping bags. It applies to all sleeping bags with the exception of those for extreme temperatures (comfort range below -25ºC) and sleeping bags used by the military. The standard was published in 2002 and has now been adopted in many countries.
•   ‘Comfort’ rating is based on a ‘standard’ woman having a comfortable night’s sleep.
•   ‘Limit of comfort’ is based on the lowest temperature at which a ‘standard’ man is deemed to be able to have a comfortable night’s sleep. This is the figure we use in our product descriptions.
•   ‘Extreme’ rating is a survival rating for a ‘standard’ woman. According to EN 13537, ‘a strong sensation of cold has to be expected and there is a risk of health damage due to hypothermia’. This is a survival rating only, and consumers should not rely on this rating for general use. The best guidelines are the comfort and limit of comfort ratings.
Comparing sleeping bags
Choosing a sleeping bag can be complicated as there isn’t a consistent, universally adopted method of rating the warmth of the bags. Many brands, including One Planet, have adopted EN 13537 as it is a reliable, scientific rating method. However, not all manufacturers have their bags tested to this standard, so care should be taken when comparing warmth claims across brands. Bags are also tested when new and clean, with bags needing regular cleaning to maintain performance.
For more information about EN 13537, please download this PDF document.
Temperature rating in accordance with EN 13537
Our sleeping bag range contains more than 60 models, not to mention the endless variations available in our custom-filled bags. It is impractical to test every model and size so, in accordance with the standard, we choose a cross-section of our range for testing, the results of which allow us to draw logical parallels to establish the performance of the rest of our sleeping bags. We continue to test new bags to increase our knowledge bank.
The tests are performed at the Kansas State University to standard EN 13537.
Your bag selection can be affected by your shoulder width and preferred sleeping position so, if possible, try before you buy. As a guide, One Planet sleeping bags are designed to fit users with the following maximum heights:
• Small – between 173–185 centimetres, depending on the model. • Regular – between 183–190 centimetres, depending on the model. • Large – between 195–205 centimetres, depending on the model.
For information about user height for specific models, please see the detailed information available in the One Planet sleeping bag chart.
Specifications are based on pre-production samples and may vary slightly during production.
The compression stuff sack provided with your One Planet sleeping bag has been designed to protect your bag from over compression. On the right is the Robin Hoodless +3 stuff sack.
However, when storing your bag for extended periods, it is important to allow the bag to expand to its full size. Current One Planet down sleeping bags come with a cotton storage sack which allows the down to loft to its full potential, preventing potential damage. You can also hang the bag in a cupboard or keep it on a large shelf: the most important thing is not to keep it in its stuff sack.
Note: synthetic bags do not come with storage sacks.
However, when storing your bag for extended periods, it is important to allow the bag to expand to its full size. Current One Planet down sleeping bags come with a cotton storage sack which allows the down to loft to its full potential, preventing potential damage. You can also hang the bag in a cupboard or keep it on a large shelf: the most important thing is not to keep it in its stuff sack.