Sleeping Bags

Sleeping bags are the best way to keep your body warm in cold conditions. Please learn about the different options available to you and look at the following helpful information.


Most synthetic bag insulation today is made from one of two material, Polarguard 3D or Primaloft. Of the two, Polarguard 3D is more popular because of it's higher durability. Primaloft offers a lighter and more compressible insulation. All synthetics will dry quickly and are more durable than goose down. Older synthetic materials used in bags such as Hollofil and Quallofil are sufficient, but are heavier and bulkier than newer versions.


Down bags provide as much warmth as synthetic bags with less weight and more compressibility. However, down bags are usually more expensive, and if not cared for properly, lose their loft very quickly. They are also difficult to dry and lose insulating power when wet. Fill power is a measure of how warm a down bag will be. Higher numbers mean more loft and better quality down. Typically fill power is a number between 550 and 850. All down bags should have a water-repellant or waterproof finish to prevent loss of loft.


What to Look For in a Bag


Make sure to check out the size of a bag in the store. Most sleeping bags come in regular and long sizes. Those people above 6 feet tall should check out long sizes. Don't buy a bag that is too big for your body as it will be extra weight to carry and extra space to warm up. To make sure you have the right size, ask the salesperson if you can sit in the bag you are planning to buy in the store.

Bag Shape

Bags come in three basic shapes: mummy, semi-rectangular, and rectangular. FOP recommends mummy bags for our trips because of the greater warmth they provide, although semi-rectangular bags will do if warm enough. Look for a bag with a hood to provide extra warmth.

  • Mummy bags are tapered for fit, wider at the shoulders and narrower at the feet. This allows you to save warmth while you sleep by decreasing the amount of space your body needs to warm up. Most mummy bags have hoods to provide extra warmth.
  • Semi-rectangular bags are an in-between shape. More tapered than a rectangular bag, but less tapered than a mummy bag, they provide warmth, but do take longer to warm up. Allows more tossing and turning room.
  • Rectangular bags are the least heat-conserving of all the shapes. They also weigh the most and consume the most pack space.

Temperature Rating

This number is an estimate of the minimum outside temperature at which the bag will keep you warm. Keep your metabolism and other sleep factors in mind when deciding what temperature rating is best for you. FOP requires 20 degree bags, however, if you get cold easily when you sleep, you may consider getting a warmer bag. Temperature ratings are guidelines only: look for a bag 5-10 degrees colder than the coldest anticipated temperature on your trip.


Check to see how compressible a bag is in the store. Stuff it into it's stuff sack and compare it to other bags when stuffed in their stuff sacks. The less space the bag takes up, the easier it will be to pack, but don't sacrifice warmth for space.


A hood is one of the best ways to improve the warmth of your bag. It adds tremendous warmth due to the fact that around 40% of body heat is lost through the head. Also, it provides a place to hide when dawn arrives.


Many bags have water repellent shells or finishes such as DryLoft, Epic by Nextec, or eVent. All shells should be lightweight materials such as nylon. They should also be durable and windproof.

Zipper Tape

A zipper with a tape along it's inside will prevent your bag from catching in the zipper. A useful feature when you are heading to the woods in the middle of the night.

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