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Triple Sleeping Bag Technical Details

The WARMLITE® TRIPLE DOWN SLEEPING BAG is the only complete backpacking “BED” for ALL temperature ranges, providing comfort in all conditions anywhere.

Warmlite® Triple Bags have THREE overlapping temperature ranges from +60° to -60°F (-75°F to -80°F reported by hardy Alaskans). And an optional net top that can extend its uses to the tropics.

Warmlite® Triple Bag gives best COMFORT, warmth, adjustability, and least weight through superior design, fabrication, and efficient use of the best materials. Multiple tops for all conditions, and a comfortable, insulating mat, block ALL types of heat loss, convection, conduction, evaporation and radiation. Our unique designs which allow for the lightest, warmest, four-season sleeping bags with vapor barrier linings have been exclusive to Warmlite® since they were designed in 1959.


CONVECTION HEAT LOSS is blocked by wind-tight, rip-stop nylon, double zippers (since 1957), closely fitted collar and fully adjustable hood (since 1958). Air can’t enter to carry away heat unless you adjust it to allow it.

CONDUCTION HEAT LOSS is blocked by highest loft 820-890 Goose Down which is held in a very uniform thickness that is not affected by your position in the bag. The bag is designed to provide the most surface area for a nights rest as close to a bed as you can obtain while backpacking. Be sure to follow our girth measuring instructions to select a bag size that will offer you the most comfort. 3″ to 4″ less girth gives less weight but also restricts motion, like a mummy bag, so be sure to take your comfort into account. A mummy bag may make people with claustrophobia uncomfortable.

EVAPORATION HEAT LOSS is blocked by our flannel like vapor barrier fabric lining. With collars snugly closed you can get up to 15°F more warmth from the vapor barrier liner. Opening the collar allows humidity and heat to escapes, removing the extra warmth. For more about vapor barrier materials read . We’ve used vapor barrier clothing since 1955 and all Warmlite® bags have had vapor barrier lining since 1968, an essential part of our sleeping bags.


Insulation always STAYS DRY. Sweat & humidity from you can’t wet it. All bags without vapor barrier lining absorb water every night from user, due to user’s sweat wicking and condensing in the insulation.

Vapor barrier helps you detect overheating quickly. You’ll open the bag to cool you when sweating begins, not after the bag is soaked with sweat, oil, and salt. The vapor barrier lining also dries before you’ve cooled down, it doesn’t need hours of drying the next day. This is also far less dehydrating, thus you’re less likely to get frost bite the next day.

It’s easy to clean with a damp cloth.


Size 56”, 60”, 64” and 70” on DAM Refers to the girth size of the sleeping bag it fits into.

Heat loss to ground is blocked with a 3″ to 4″ thick, full size 1 and 1/2 pound Goose Down filled Air Mattress (used since 1975), for the soft comfort & light weight of an air-mat (which are usually cold), and WARMTH of Goose Down (in other bags Down is destroyed by lying on it). Using the DAM saves the user from the bulk and weight of covered foam pads (or even heavier ‘self inflating’ foam cored air-mats.) We also offer +1 pound, 2″ thick foam pad (used since 1966) in place of a DAM (which is still lighter and more compact than ‘self inflating’ foam air-mats).
The DAM slides into a pocket inside the Triple Down Sleeping Bag, they can be stored together while on a trip. With pad locked inside the bag you won’t roll off it, or turn the Down insulation into pieces of string by lying on it. Internal net baffles block the Down from shifting.

We made the first Down filled air-mat in 1959 and learned to produce them in 1975. The fabric is very tough, coated nylon taffeta, the strongest used in any air mats. We use a Radio Frequency Thematron machine to weld the pieces and fabrics together. Since its production, its performance has exceeded all expectations, with life a expediency of well over 20 years. We use the color orange so that in case of an emergency the DAM can be used to attract attention from Search and Rescue or other hikers. It can also be used for a swim or fishing float or, in a worst case scenario, will float you and your bag if the creek rises and floods camp. It inflates fast and easy with the carry sack used as a pump (never by mouth) or with the Microburst inflators.


RADIANT HEAT is greatly reduced when inside a tent or under heavy foliage. The silicone coated nylon used on our tents and footprints is a standard on our tents and will protect the user from radiant heat loss and condensation.


After trying about every possible foot end design, we found that the simple extended foot space was best, allowing your feet to relax in a normal position no matter how you sleep in the bag. Other ‘contoured’ or fitted foot ends all restrict foot spread and are uncomfortable for sleeping on your side or stomach.


Even at the zippers there’s no insulation loss. Parallel zippers separately close inner and outer surfaces. Separating zips on each side, and across the foot give independent venting and allow you to zip bags together on EITHER side, or join the tops together for a very wide, warmth-adjusting top. Use tops zipped together for a quilt on your cabin bed. In very cold conditions, to dress inside, or for fine tuning from -50° to +10°, using both tops, unzip tops on opposite sides to let the bag expand as needed.

In 1987 we advanced to the excellent YKK #3 zippers for bags, these provide the least weight and the least snags. Our experience with YKK #3 on bags since 1987 has been as flawless as on our tents since 1970. Heavy zippers used by other companies snag fabric which spreads the slider and makes the zipper come apart.

diagram of sleeping bag


The unique Warmlite® hood design evolved as a way to permit full head protection when sleeping in any position. Most hoods can only be closed if you lie on your back. Our hood zips up over the shoulders and snugs up over or around the head with the top drawstring, so it can close snugly around your face or nose when you’re on your back, or adjusts to cover your head and leave breathing space when lying on your side or stomach. It may take time to get used to, but it is the most flexible and adjustable.

For safety we use non-lock zip sliders, if you wake with your head in the bag, a good push will open the hood immediately. We also install Velcro tabs across the zippers at two positions that take more than a small amount of force to pass, this stops the zippers from drifting open. You can add tabs for more positions if desired.


The standard Warmlite® Triple Down Sleeping Bag includes both the thin (1.8″ thickness= 3.6″ “loft”) and thick (3.8″ thickness= 7.6″ “loft”) removable tops (equivalent to 11.2″ loft combined), attached with parallel rows of separating zippers along each side and across the foot, so there can be no cold zipper line when thick or both tops are used. Usually the thin top is used in temperatures down to 25°F (summer range), the thick top down to -10°F, and the combination for quick warmup or winter use for temperatures down to -60° F (- 75 to -80 reported by hardy Alaskans!).

Comfort ranges are greater than any other bag of similar thickness due to controllable warmth from vapor barrier. Uniform thickness and dual zips allow you to move as you wish and stay warm, so you won’t get stiff and sore from staying in one position all night. You may have experienced cold nights in bags with separate pads where any attempt to roll over makes you cold when crushed insulation below is exposed, you soon learn “don’t move”, then wake up stiff & sore.

For the tropics, we offer the optional NET top, a double layer of fine noseeum net held 3/4″ apart with many foam spacers. Bugs on the outer layer can’t reach thru to you.

For use outside a good shelter spray on water repellent or a Warmlite® water proof cover/bivy are best for dew or drip protection. A Warmlite® Footprint works best for ground protection, as well as giving an area for your pack, boots and other gear.


We use a silicone coated nylon as the standard fabric for best Vapor Barrier, least weight, best durability, and variety of colors.

The bottom interior is Fuzzy Stuff, a comfortable, brushed-knit Nylon and tough, stretchy, urethane film. It wears better than coated fabric, is best for comfort, and provides a long life. The surface feels like soft flannel, but wicks sweat across it’s surface fast for rapid drying and comfort.

Fuzzy Stuff is used on bag bottom interior where comfort, extra wear resistance, wickability for fast drying, and easy cleaning is needed, but not on tops: it clings slightly to clothing, weighs more, and more toughness isn’t needed on tops. On top interior we use coated, water-proof fabrics, so that a vapor barrier is maintained but also doesn’t stick the user to the bag, preventing ease of movement. Colors vary, though we do our best to pick compatible interior colors. If you would like a sample of a color email us!


Fabric is the finest 30 denier Down proof rip-stop nylon with soft, water repellent finish. Used since 1958 without failure, it’s obviously too durable, but there’s no lighter Down proof fabric! Every part is cut with a hot-knife, which is the only way to keep seams together. All others hide raw knife cut edges with binding tape or flat felled seams, but that won’t keep them from pulling apart. Usual colors are red, blue, or green, but you can choose any coated fabric color we offer.

Each bag is individually sewn by a highly skilled seamstress working from home. All sewing is with 100% Nylon thread to match fabric strength, stretch, softness and super wear resistance. Cotton or polyester thread make stiff seams that don’t wear well. The highest loft most mature Goose Down available is carefully hand weighted into each pocket, in a sequence that assures designed uniform loft.

Contoured direct tension vertical baffles, closely spaced, maintain uniform loft no matter how you move in the bag, yet allow control of insulation. If too warm, pat the sides to allow the Down to fall to the sides to stop some insulation. If cold, gently pat from inside, expanding Down to fill tubes for more warmth.

The cost of a Warmlite® Triple Down Sleeping Bag may seem high, but it includes much more than other sleeping bags. Compared to other bag combinations needed to match it, the overall cost would be higher and would require multiple items such as a winter bag, a summer bag, an overbag, a VB liner and 2 self inflating pads to match the warmth and comfort of D.A.M. All of this is included in one Warmlite® sleeping bag, all while being the warmest, lightest, most durable, and most adjustable for personal comfort, preference, and any weather condition. Not only are all of these features present in one bag, but they are designed to be compatible with each other, you don’t have to try and make one item work with another, it also saves on storage space in your home and on a trip. Why buy 2 or 3 other bags to cover a range of climates and be unsure of which bag to take, or worse, find you’ve taken the wrong one, when one Warmlite® bag does it all? Many outdoor enthusiasts buy limited range single top bags to save money, but when another bag is needed for other conditions, the cost doubles. Weather is unpredictable, a non adjustable bag can leave you dangerously cold or miserably sweaty. With a Warmlite® Triple you get best materials and features, 3 bags and a pad with the weight of only 1 1/4 bags.

We’ll custom make thinner lighter Triple Down Sleeping Bags and special Single top bags if needed, but expect alternate suggestions from us if our experience indicates your stated needs will be better met with something different. We would rather you were still happy for many years from now, not just pleased with us before you get the product!

Warmlite® bags are stocked in 4 girths with standard heights, in red, blue or green. We can make them to order for any height, any girth, and any color(s) we have. When ordering give us your height, weight, girth measurement (see measuring sketch), desired bag girth (and why, if different from measurement), whether you’ll take standard height bags for that girth or want it custom made to your height, type of bottom pad (D.A.M. or Foam), and color choice(s). If rushed, call to check stock. Production may take 4 to 12 weeks.


LIFE OF INSULATION: If you lie on the insulation in your sleeping bag or parka, and then move sideways to turn over, you put shearing force on the insulation. That tears synthetic insulations, and rolls Down into pieces of “string” from which it will never recover. Stuffing your bag or parka does the same thing, as well as puting excessive loads on the seams. Prior to 1966 we had people bring 2 to 3 year old bags in to restore loft, and we found the lost loft was entirely due to “strings” of Down caused by lying on it. Since 1966 our bags with pads in them have never had that problem. If you are using a bag loose on a separate pad, put some straps on the bag bottom to hold it securely to the pad, and shift as much of the Down out to sides and top as you can so you won’t lie on it. To pack a bag, always carefully fold and roll it. Uniform end compression of the roll to fit in a sack won’t harm it. Don’t stuff anything you don’t want to rapidly destroy!

WASHING AND DRYING DOWN: Squeeze, do not wring, water out of sleeping bag and allow to air dry. Never machine wash or dry clean. Spot clean with a wet rag as necessary. A simple test will show that equal dry thickness of Down will dry much faster than synthetics. As Down dries from the surface, interior moisture wicks to the surface where it has access to dry air and heat for rapid evaporation. With synthetics the surface lofts and insulates the interior so it takes much longer to get the needed heat in and the water out. BUT, if you saturate a Down bag and let the Down all clump together, drying will take much longer: you have greatly reduced surface area and greatly increased thickness to be dried. Thus the stories of Down being slow to dry! Those stories are correct when you put them in context. Wool is similar to Down in wicking ability and moisture holding, but being available only in dense heavy woven form it doesn’t compress as it gets wet (it’s already compressed). Both Down and wool can absorb many times their weight, within the fibers, with no effect on insulating ability. Add more than about 5 times their dry weight and Down starts to collapse and lose insulating ability, while air spaces in wool fill up and you lose insulating ability. In each case people get misled, not realizing how close to total collapse their nice Down bag is after 5 or 6 nights without inside vapor barrier, or thinking their wool shirt can continue to keep them warm without rain gear.

WHY DOWN? Polyester fiberfill is usually the lightest practical insulation per inch for clothing. Good Goose Down is much lighter, but weight of extra fabric used in construction usually offsets the reduced insulation weight. Only in the very thick insulation needed for sleeping bags is the great advantage of Goose Down really important. When comparing the numbers between Goose Down and Polyester for the same insulation they are ALL much heavier than good Down bags, yet cost just as much. Poor quality duck Down can have loft as low as 200 per pound while the best fiberfills can have an initial loft of 200 to 300 cu. in. per pound. However, synthetics lose that initial loft rapidly from regular use such as lying on and packing it. Thus, they can be as good as the worst quality Down when new, but are never anywhere near as good as good quality Down.

SLEEPING MATS: We often hear of people using short or narrow pads to save weight. When sleeping you need more insulation at your feet since you are no longer producing lots of excess heat in your legs and feet as you do when hiking. If your pad isn’t wide enough to support your arms when on your back you won’t be able to stay comfortable and won’t sleep well. It’s good to minimize weight, but you can carry much more IF you get a good comfortable night’s sleep.