Double sleeping bag: what the label really tells you
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Quick answer
A double sleeping bag fits two people in one bag, but check what its temperature number means. TETON's Mammoth 0°F Double uses a survival rating, and TETON lists its comfort range as 25 to 30°F. Kelty's Tru.Comfort Doublewide 20 lists a 20°F rating, a 64 x 83 inch size and 9 lb 8 oz. REI suggests choosing a bag rated 10 to 15 degrees below the coldest night you expect. You can also zip two matching bags together, one with a left-hand zip and one with a right-hand zip.
Three double bags compared
| Spec | Kelty Tru.Comfort Doublewide 20 | TETON Mammoth 0°F Double | TETON Mammoth 20°F Double |
|---|---|---|---|
| Rating on the label | 20°F | 0°F (survival) | 20°F (survival) |
| Comfort range listed | Not listed separately | 25 to 30°F | 45 to 50°F |
| Size | 64 x 83 in | 94 x 62 in | 94 x 62 in |
| Weight | 9 lb 8 oz | 19.4 lb | 16.51 lb |
| Packed | 15 x 26 in stuffed | 28.75 x 16.25 x 15.25 in | 26.5 x 14.5 x 13.75 in |
| Insulation | CloudLoft synthetic | SuperLoft Elite hollow fiber | SuperLoft Elite hollow fiber |
| Converts | Zip-off top layer | Unzips into two camp comforters | Unzips into two camp comforters |
The Mammoth 0°F weighs about twice as much as the Kelty (19.4 lb against 9.5 lb), so both are car-camping bags rather than backpacking bags.
Survival vs comfort ratings
The number in a sleeping bag's name is not always the temperature you will sleep well at. TETON says its listed ratings are survival ratings: the coldest temperature the bag is designed to keep you alive in, where you may be shivering. TETON suggests adding 20 to 30 degrees to find comfort, and lists the Mammoth 0°F at 25 to 30°F and the Mammoth 20°F at 45 to 50°F.
REI explains the lab ratings used across the outdoor industry: the comfort rating is where a cold sleeper might feel comfortable, and the lower limit is where a warm sleeper might. REI's rule of thumb is to take the coldest night you expect and look for a bag rated 10 to 15 degrees lower. Kelty lists the Doublewide as a 20°F bag without naming which kind of rating it is.
Sharing warmth: one big bag or two zipped bags
- Double bag: one shell, one zipper system, room for two. The Kelty has built-in blankets on each side and two foot vents so each sleeper can adjust, and an oversize hood that fits standard home pillows.
- Two bags zipped together: REI suggests zipping two compatible bags from the same brand, one with a right-hand zip and one with a left-hand zip. That keeps two separate bags for trips you take alone.
- Hot nights: REI suggests checking whether the top detaches so it can work as a blanket. Kelty's top layer zips off, and the TETON Mammoths unzip fully into two comforters.
Size, fit and the tent
- Height: Kelty says the Doublewide fits sleepers up to 6 ft 6 in.
- Floor space: the Mammoth's 94 x 62 in footprint is larger than the Kelty's 64 x 83 in; check your tent floor before you buy.
- Pads: REI notes real-world warmth also depends on your sleeping pad, so plan insulation under both sleepers; our cold-weather sleeping bag guide covers a warm pad.
- Storage: TETON packs both Mammoths in compression sacks; the 0°F is still nearly 29 in long packed.
Using a double bag for emergencies at home
A double bag can serve as a large blanket during a winter power outage, since both TETON Mammoths unzip into two comforters and the Kelty's top layer zips off. Pick by comfort range, not the label: for a cold house, TETON's 0°F model lists comfort to 25 to 30°F, while the 20°F model lists 45 to 50°F.
Both brands use synthetic fill, and REI notes synthetic fibers break down and lose some warmth after years of being compressed in a stuff sack. Between trips, REI suggests draping a bag from a hanger in a closet if you have space.
What to look for when you buy
Lighter couples bag: Kelty Tru.Comfort Doublewide 20
Best for: Car camping couples who sleep at different temperatures
Kelty lists a 20°F rating, 64 x 83 in, 9 lb 8 oz, built-in blankets for each side, two foot vents, a zip-off top layer and a hood that fits home pillows.
Watch out: Kelty does not say whether 20°F is a comfort or limit rating; add a margin for cold nights.
See options on Amazon (opens Amazon in a new tab)Cold-weather double: TETON Mammoth 0°F Double
Best for: Fall and winter car camping, or a backup blanket for a cold house
TETON lists a 94 x 62 in bag with a comfort range of 25 to 30°F, a flannel liner and full zippers that let it open into two camp comforters.
Watch out: It weighs 19.4 lb, and 0°F is a survival rating, not comfort. The Mammoth listing also offers a 20°F version rated 45 to 50°F comfort.
See options on Amazon (opens Amazon in a new tab)Questions people ask
- Are double sleeping bags warmer?
- Warmth depends on the bag's rating, insulation and your pad; check the comfort range, since TETON's 0°F double lists comfort at 25 to 30°F.
- Can you zip two sleeping bags together?
- Yes, REI says compatible bags from the same brand can zip together if one has a right-hand zip and the other a left-hand zip.
- How big is a double sleeping bag?
- Kelty's Doublewide measures 64 x 83 in and TETON's Mammoth 94 x 62 in; measure your tent floor first.
- What temperature double sleeping bag do I need?
- REI suggests a bag rated 10 to 15 degrees below the coldest night you expect, using the comfort rating where listed.
Sources
- Tru.Comfort Doublewide 20 Sleeping Bag, Kelty
- Mammoth 0°F Double Sleeping Bag, TETON (Teton Gear)
- Mammoth 20°F Double Sleeping Bag, TETON (Teton Gear)
- Sleeping bags for camping: how to choose, REI Co-op Expert Advice
- Carbon monoxide questions and answers, U.S. Consumer Product Safety Commission