Gear of the Month.
If you are attempting high-altitude or chilly weather expeditions or even camping trips, then then you are at the right place. This issue of Cross the Line focuses on one of the most important gear that gives your body much-needed insulation and thermal protection while you are taking rest and preparing for the journey ahead.
Although camping trips are usually done with quilts, or blankets, or both, a sleeping bag is a necessity when you are doing high-altitude climbs or cold-weather camping trips, where the temperature drops dramatically after sundown.
To know more about how sleeping bags have become an indispensable gear for trekking and other mountain expeditions, read on.
Importance of sleeping bags:
Sleeping bags provide you warmth by trapping the warm air around your body. Your body heat is instantly captured by the filling of the sleeping bags - the mechanism similar to a duvet in the case of a bed.
Air is a poor conductor of heat but it's a good insulator, and hence it traps the warm air around your body and keeps you warm.
Types of sleeping bag according to insulation provided are -
- Synthetic insulation and
- Down insulation.
Synthetic insulation is heavier and bulkier but dries out quickly and maintains some amount of warmth even when damp. If you want high-end synthetic insulation bags, then you can go for brands such as Primaloft, Qualofil, Thermolite, Climashield, etc.
Synthetic insulation bags that are made of short filaments are not durable because they break down easily. Those synthetic insulation bags that are made of long filaments are durable and provide good insulation but are not easily foldable.
On the other hand, down insulation consists of small down feathers from ducks and geese - packs down well, are lightweight, durable, but comparatively expensive than synthetic insulation. Also, one of the challenges is that once down insulation sleeping bags get wet, they are difficult to dry, and they won’t provide any warmth.
Dry down insulation is a recent innovation where the filaments of the feathers are coated in hydrophobic coating to prevent dampness. However, we should all try to use a bag that is ethically down and does not treat the ducks and geese inhumanely.
How to decide which filling is ideal for you?
- Weight and bulky on long trips - use down insulation as it is lighter and compresses well.
- Damp - if you are carrying a sleeping bag that might get damp and not dry easily, carry a synthetic one.
- Extremely cold - during such temperatures, a down sleeping bag has the best weight to warmth ratio
- Cost - down insulation is more expensive than synthetic insulation but durable in the long run.
Sleeping bag temperature rating:
The rating system provides a range for the bags. These are -
- Upper limit - At this temperature, someone will be able to sleep inside the bag with the zip open and their arms and head out. If the temperature is higher, then they will be sweating profusely.
- Comfort temperature - It is the temperature at which somebody will be able to sleep comfortably within the bag.
- Lower limit - At this temperature, someone will be able to sleep inside the bag for 8 hours without waking up due to the cold.
- Extreme - This is the minimum temperature at which somebody will survive inside the bag for 6 hours without hypothermia.
Sleeping bag materials:Filling
The main factor of a mountain sleeping bag (usually mummy-shaped) is the filling. The amount and nature of the fill decides how much warmth it can preserve considering the lowest temperature you are going to experience.
Your body compresses the sleeping bag due to its weight, therefore, on cold terrains, the bags are as good as the insulating mat and the warmth provided.
Liners are generally made of -
- Silk or synthetics (microfibers or polyester)
- Cotton or fleece.
Silk and fleece insulate and add extra degrees of warmth to the bag whereas cotton and synthetic ones keep the bags clean from the inside out.
Fleece sleeping bags are bulkier but cater to a range of temperatures. You might use to sleep inside it on the mountain-top, but at the basecamp where it is much warmer, you can use the fleece sleeping bag as a duvet.
Silk liners are lighter, pack down smaller, but don’t pack in as much warmth as the fleece liners.
Cotton liners are great for jungle adventures where it is hot and humid, and you might not require sleeping inside a sleeping bag. They are good for indoor use.
State-of-the-art advanced synthetic liners use hollow-core Thermolite fiber and 3D-knitted structure that traps air nicely and can be used as a standalone sleeping bag.
Best sleeping bags:
Some of the most well-known sleeping bags globally are:
- Best overall sleeping bag - Marmot Phase 20F Degree Down
- Highly dependable - Sea to Summit Ascent Ac1
- Best durability - Coleman Green Valley
- Best insulation - Kelty Cosmic 20 Degree Down
- Adventure friendly - Vango Nitestar 350
Of course, there are many local brands who make high quality sleeping bags as well. Do consider the nature of your trip, your budget and other factors that we discussed above when you buy or rent a sleeping bag for your next adventure.