How to Buy a Sleeping Bag

It’s quite possible you read the heading and snickered. “How smart do you need to be to buy a sleeping bag?” Well, not real smart I guess. I’d prefer to say informed. But when you wake up mid-night in the wilderness freezing, and your com-padres are snoozing toasty warm, you may want to revisit the question of intelligence. Just for grins let’s examine some requirements you may want to know before going sleeping bag shopping.

Analyzing a Sleeping Bag’s Temperature Rating:

Number one … realize temperature ratings are an estimate, not a concrete fact as a person’s individual metabolism will make a huge difference. Some manufacturers assume the person is wearing long underwear and have a sleeping pad beneath them, and this may or may not be identified in the labeling. There’s nothing dishonest going on here, just keep in mind temperature rating is a guide. It’s intended to say a 35 degree bag should, under normal circumstances keep a person reasonably warm at that temperature.

I go by the manta of better to have it and not need it .. than need it and not have it. Therefore, I strongly suggest you error on the side of caution. If a sleeping bag is rated for 35 degree F … you may encounter colder weather, buy the bag rated 20 degree F. You can always shed clothes or increase ventilation if the weather is too warm.

Sleeping Bag Shapes:

Yes, sleeping bags come in different shapes and sizes. Sizes? OK. But shapes? Allow me to expand. The theory, and practical application, of a sleeping bag is to trap and hold a layer of dead air inside the bag next to your body. Your body heat warms this air and insulates you from the colder air outside the bag. The less air to heat, the faster you heat up and the warmer you stay. This is based on shape, although size also plays a part, as usual there are trade-offs. Larger bag … more comfortable as far as roominess, but harder to heat. Smaller bag … less comfort, but easier to heat.

Rectangular shape is the most popular shaped bag, designed for maximum roominess, and is intended to be compatible with other rectangular bags in order to join the two together offering a double bed instead of a single. The only catch is, one bag must have a right hand zipper and the other a left hand zipper. (Left hand zipper means it opens and closes to your left as you lay on your back) Be aware the zippers must be the same style, size and length. It’s best to ask for expert advise if there’s any doubt as to whether the two bags are compatible.

Semi-rectangular bag (barrel-shaped)

The tapered design of this bag offers greater warmth than rectangle bags while also allowing adequate room for a restless sleeper to function. Larger framed people may find this to be the best choice for them.


Mummy Style


Claustrophobic people could never use this shaped bag. It’s designed to maximize warmth, but also to reduce weight for a hiker to carry. It does this by having a narrow shoulder but wide hip allowance for squeezing into. Again, trade-offs.


This bag is designed for maximum comfort. Two people can easily sleep together and couple that with an air mattress or foam pad and it’s cozy and comfortable. An extra benefit is most of these bags are designed to come apart and form two individual bags.

Insulation: Sleeping bags come with various types of insulation.

Synthetic-fill Insulation: The majority of people choose synthetic insulation and with good reasons. Synthetic insulation, made of polyester, is price-friendly, quick drying and insulates even if wet. It’s overall performance is excellent and its durable and non-allergenic. However, synthetic insulation does not pack down as small as down insulation therefore its less versatile for backpacking.

Goose-Down insulation is a durable and more compressible alternative, but carries a higher price tag. The huge downside to goose-down is it loses its insulation factor if it becomes wet, therefore some bags come with feathers that are chemically treated to resist moisture.

***Note*** Never store your sleeping bag rolled up or in a storage bag, as the insulation will retain that memory, which will create a problem of the bag remaining flat.

Hang the bag up on a hanger fully unrolled.

Additional Sleeping Bag Options: Just like a new motor vehicle which comes in the basic package with available options, sleeping bags are no exception.

Sleeping bag shell and/or liner: Nearly all sleeping bags have an outer covering (shell) made of rip-stop nylon or polyester for durability. A large portion of synthetic bags offer a shell treated with what is known as a durable water repellent, which prevents the fabric from soaking in moisture. You can tell if the bag has been treated by exposing it to water, if it beads up, it’s treated. Some bags are made with a liner that is designed to disperse body moisture, therefore the bag must be able to breathe. These bags will not be treated. Again … trade-offs. Just be aware of which type you are buying.

Sleeping Hoods: Every outdoors person knows the greatest body heat loss is through the head. There are semi-rectangular sleeping bags that have a built-in hood, which when cinched tight with the draw cord, prevents heat from radiating out. Most will offer an attached pillow pocket that can be stuffed with clothing to create a soft pillow.


Sleeping Pad

Other Pockets: A stash pocket allows for a storage space for small items like a watch, eyeglasses or MP3 player. A sleeping pad sleeve pocket is a sleeve for inserting a sleeping pad into to prevent rolling off it at night. A pillow pocket is just that, it forms a space for you to make a pillow out of clothing or a camping pillow.

Sleeping Bags Designed For Women & Children

Women need winter sleeping bags that are rated 5 to 10 degrees warmer than men, therefore they are specifically designed to match a woman’s contour, narrower at the shoulders, wider at the hips and shorter. Most have added insulation in the foot-box and upper body area.

Kid’s sleeping bags are of course smaller. Some feature a built-in sleeve on the bottom of the bag to hold a sleeping pad. Pillow pockets & exterior pockets allow storage for headlamps, MP3 player, pocket knife and etc.


Rectangle Shaped Bag

Classifying What Type of Sleeper You Are:

Sleeping bag ratings and construction are not the only variables to consider when buying a bag. What type of sleeper you are has a direct effect on what you need to buy. So how do you tell what type of sleeper you are? Use this as a guide: Your house temperature is set at 65 degrees F when you go to bed.

A hot sleeper will begin with few if any sheets or covers, but as the night progresses the covers disappear as you kick them off because you are too hot, and/or your partner may complain about how much heat you radiate.

A cold sleeper will pile every available cover over them, covering their head and seldom moving during the night. This occurs because the person has a slow night time metabolism, creating very little body heat, which requires the extra covers to stay warm.

Now apply the type of sleeper you are to the “general rule of thumb” when rating a bag. If you’re a hot sleeper, the bags temperature rating is probably suffice for you. However, if you’re a cold sleeper assume the rating too high. In other words, a 20 degree rating will only keep you warm if the temperature is 30 degree F.

Additional Factors: For added comfort adhere to these tips.

Use a hood with a drawstring.

Keep the bag fully zipped, which may sound like a no brainer, but many people will partially unzip the bag in order to allow more freedom of movement.

Buy a properly sized bag. If you are 5′ 9” don’t buy a bag designed for a 6′ 3” person as a cold pocket of air will form at your feet if the bag is too large and prevent your feet from being warm. Cold feet equals cold body.

Use of a sleeping pad is mandatory at all times as laying directly on the ground will suck heat from the body no matter how good the sleeping bag. Moisture, even if it does not penetrate the bag, will chill the enclosed air which is suppose to provide a heat barrier.

Summing things up. It is wisest to buy a bag that provides an extra 15-25 degrees better temperature rating than you think you’ll need. It offers more flexibility for additional or unexpected environments and you can always partially unzip the bag to allow for ventilation if you are too warm. Remember, there’s all types of ways to cool a sleeping bag down, but none to increase the warmth.

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