How Does a Sleeping Bag Work?

To begin with, it's important to remember that no sleeping bag can generate heat for you. Instead, it helps retain the heat your body produces. When you get into a sleeping bag, it's like placing a heat source of 37°C inside it. In an ineffective sleeping bag, heat escapes through the fabric, filler material, poorly sealed zippers, and improperly designed head openings. A good sleeping bag, however, works in harmony with your body to create a comfortable sleeping environment and efficiently retain heat.

Make sure to enter your sleeping bag dry, well fed, and warm. Complete your nightly routine and do a bit of exercise to warm up your body before getting into the bag. Be sure to close the bag properly around your head. Wear light underclothes, add socks or use our sleeping sock and wear a wool beanie in winter.

If you still feel cold despite these measures, avoid adding more clothing inside the bag. Instead, drape a down jacket over the bag or add more insulation beneath you.

Temperature testing and how it works:

The EN (European Norm) was the first standard used by the sleeping bag industry. Now, the ISO (International Standards Organization) handles sleeping bag testing with a method that's almost the same as the EN test. Since ISO testing is very similar to EN testing, you can easily compare an old EN-rated sleeping bag with a new one that has an ISO temperature rating when shopping.

Helsport Comfort Temperature:

• In the temperature range of +15 C to -5 C it is expected that you will wear short underwear and a T-shirt in your sleeping bag.
• In the temperature range from -5 C to -20 C you are expected to wear a thin “1st layer” that is normally a set of thin, long woollen underwear.
• When it is colder than -20 C you will normally use a thin 1st layer and in addition a 2nd layer on your upper body.
• Women should add 4-5 C to the comfort temperature in outside temperatures down to -15 C.
• Women should add 8-10 C to the comfort temperature in outside temperatures below -20 C.
• Those older than 30-35 years you should add 5 C to the comfort temperature.
• If you are going to altitudes above 3.300m you should add 5-10 C to the comfort temperature.

These lab tests give a range of temperature ratings for each sleeping bag:

TCOMF: The green zone is called the "comfort zone", and in this temperature range most people will be able to sleep comfortably.

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).

TLIM: 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.

For all our sleeping bags, we use the comfort temperature rating to ensure your well-being and make sure you are as comfortable and well-rested as possible. We believe this approach creates a better and safer experience for you.