Initial Report:
MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag

Product Information
Manufacturer: Mont Bell Co., Ltd (MontBell)
Manufacturer Website: http://www.montbell.com
Product Tested: MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag
Year of Manufacture: 2006
Color: Balsam (blue-green)
Sizes Available: Regular (user height to 70 in/178 cm) , Long (user height to 76 in/193 cm)
Size Tested: Long
Weight Listed: 22 oz (624 g)
Measured Weight: 21.15 oz (600 g) (scale accurate to 0.01 oz/0.1 g)
Insulation: 725 fill-power Gray Goose down
Fill Weight: 10.6 oz (301 g)
Inside Shoulder Girth:  48.2 in/122 cm relaxed, 64.2 in/163 cm expanded
Inside Knee Girth: 38.4 in/98 cm relaxed, 51.2 in/130 cm expanded
Packed Size: 5.3 in x 10.4 in (13.5 cm x 26 cm)
MSRP: $255 US

Product Description
The MontBell Alpine series is their lightest and most compressible sleeping bags. The Ultralight Alpine Down Hugger #3 is a down-filled sleeping bag rated at 32 F (0 C). Its features are as follows (taken from the MontBell website):

• 725 fill power goose down is hypoallergenic and resistant to moisture
• Shell and lining are 15x24 denier Ballistic Airlight^™ hollow fiber calendared nylon with DWR treatment on the outside
• Vertical baffles maintain the even distribution of down while allowing the down to loft completely
• Gathered Quilt System draws the insulation closer to the body and keeps heat in the bag
• Full length zipper for easy entry and double sliders for temperature regulation
• Draft tube prevents cold air from entering the bag through the zipper
• Double compression stuff sack allows the bag to be compressed to a very small size.
• Bottom Adjustor System is a drawcord at the foot that allows the length of the bag to be adjusted to the user’s height, and allows the user to create a “bootie” around the feet for extra warmth.
• Cotton bag provided for longer-term storage

Initial Impressions
The Alpine Ultralight Down Hugger #3 is impressive to look at. The shell is very lightweight and soft to the touch, yet appears to be downproof. The bag has quite a few features, including a full-length zipper, despite its light weight. When I got inside the bag, I found it has plenty of length and girth to accommodate my frame, plus a few extra clothes for extra warmth when needed. 

Based on the information and photo (see top of page) provided on the MontBell website, the bag met all of my expectations, except loft. For a bag with a 32 F (0 C) rating I expected at least 2.5 in (5 cm) of single thickness loft, but the bag barely has 2 in (5 cm) of loft. I held the bag up to a strong light and discovered that some chambers in the chest area have little or no down. The fact that it is 0.85 oz (24 g) underweight concerns me; that extra amount of down in this bag would make a significant difference. I shook the bag vertically and horizontally and that helped to distribute the down a little better.

Test Plan
The MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag will be my primary sleeping bag during the four month test period and will be used as much as possible.

Test Period—The test will run from mid-April to mid-August 2006.

Test Locations—Southwestern US (Colorado, Utah, New Mexico, and Arizona).

Testing Conditions—The testing environments will consist of: canyon country, forests, and alpine terrains. Elevations will range from 5000 to 12,500 feet (1524 to 3810 m). Expected extreme conditions include: strong winds, dust/rain storms, heavy rain, low temperatures, and high elevations with strong UV and intense thunderstorms. I expect to test the bag at temperatures both above and below its temperature rating, and in wet and dry conditions.

Activities—The MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag will be tested in the following activities: 1) backpacking, 2) car camping.

Specific Tests—I will determine how well the shell’s DWR treatment repels moisture and keeps the down dry. I will also test the bag while sleeping under a minimal poncho tarp in rainy weather, again to determine if it sheds surface moisture and stays dry inside. Further, I will sleep in a damp meadow under the stars to determine how well it sheds dew. During the four month test I will use the MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag in several different shelter systems, including a bivy, poncho/tarp, single wall tent, and double wall tent.

Data—On each trip I will record the following data in relation to my comfort sleeping in the MontBell Alpine Down Hugger #3 Sleeping Bag: 1) temperature in my shelter and outside, 2) estimated wind speed, 3) estimated humidity, 4) altitude, 5) precipitation (including what form), 6) sleeping system the MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag was used in, 7) clothing worn inside the bag, and 8) how well it performed in terms of warmth, utility, and comfort.

Factors Evaluated
Below are the specific factors on which I will evaluate the MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag. I have provided some information in this Initial Report. As the test progresses, I will answer the questions raised, and update information as needed.

Materials, Quality, And Construction—The Ballistic Airlight^™ hollow fiber calendared nylon shell is very lightweight and has a soft feel, yet seems to be durable and downproof. I looked over the quality of the sewing and other details, and found that it is very well made.

Sizing—According to MontBell, the size Long bag will fit users up to 6 feet 4 inches (193 cm), and I agree. I am 6 feet tall (183 cm) and there is plenty of length to spare. MontBell specifies that the shoulder area will stretch out to a girth of 64 inches (163 cm). I got into the bag while wearing a down jacket and pants and found the girth ample to accommodate extra clothing. So far I have not noticed any down compression from the bag is too tight.

Features—Although this is an ultralight sleeping bag, it still has several useful features. The main features are: full-length zipper with double sliders, down-filled draft collar behind the zipper, hood with drawcord closure, elastic seams that draw the sleeping bag around the body, and a drawcord closure at the foot. The bag does not have an interior pocket or a neck draft collar.

Insulation And Loft— The bag is insulated with 10.6 oz (301 g) of goose down. It has a vertical box construction in the torso area with vertical baffles parallel to the user's body. This holds the down in place, preventing it from shifting to the sides of the bag. However, unlike continuous baffles, it does not allow the user to redistribute the down (for example more down on top) for extra warmth where desired.

To measure the bag’s loft I thoroughly shook the bag vertically and horizontally, then laid it on a table for 24 hours to allow the down to fully expand. Then I held a yardstick horizontally over the bag at several locations and measured its double-thickness loft with a ruler. The average double thickness loft was approximately four inches (10 cm). Dividing by two, the single thickness loft is approximately two inches (5 cm).

As a rule of thumb, it requires about 2.5 to 3 inches (6 to 7.5 cm) of single layer loft to achieve a comfortable temperature rating of 32 F (0 C). The MontBell Alpine #3 only has two inches (5 cm) of loft, so its temperature rating may be optimistic. I found the bag to be underweight by 0.85 oz (24 g), and that amount of extra down would certainly increase the loft significantly. Also, for an expensive ultralight sleeping bag, 725 fill-power down is low by today’s standards. MontBell should consider using at least 800 fill-power down.

Convenience—The horizontal seams have an elastic stitching that causes the bag to hug my body when I am inside. I found it easy to move inside the bag, with the bag easily expanding to accommodate my movements.

In my opinion, the stuff sack provided with this bag is too small. It takes a lot of effort to stuff the sleeping bag into the small sack, and then there is a second drawcord to pack it down even smaller! MontBell promotes the compressibility of this bag, so it takes up little space in a backpack. However, I personally feel that too much compression damages the down, and prefer to use a larger stuff sack that the bag more easily packs into (however it does take up more space in a pack).

The shoulder girth of this bag expands to 64 inches (163 cm), which is very roomy and will allow lots of space to wear additional clothes inside the bag to extend its warmth. The “hugger” feature appears to be a good approach to offer a sleeping bag with plenty of girth to accommodate people of different sizes, yet pull the down close to the user’s body for extra warmth.

How smooth is the zipper to operate? Does the zipper snag easily? How easy does the hood tighten and loosen?

Comfort/Warmth—Does the bag meet its 32 F (0 C) temperature rating, i.e., is its rating optimistic or conservative? Is the hood adequately insulated? Does the bag have sufficient draft collars to seal out drafts? Does the shell fabric breathe well, so body moisture is not retained in the bag? Are the zipper and hood draft free? Does the down stay evenly distributed in the baffles, or do cold spots develop?

Usability And Performance—How well does the bag perform in the field under a variety of sleeping systems and weather conditions? Is the shell fabric adequately down-proof? How does the top/bottom distribution of down effect its warmth? How well do its elastic “hugger” cords improve the bag’s warmth by decreasing the volume I have to heat? Is the bag’s girth large enough to wear clothing inside the bag to extend its warmth? Is the stuff sack lightweight and the right size for the sleeping bag?

Water Resistance—How well does it shed dew or a light shower? Does the MontBell Alpine Down Hugger #3 Sleeping Bag’s DWR treatment eliminate the need to also carry a bag cover or bivy sack when sleeping a poncho/tarp?

Breathability—How breathable is the shell; does it readily allow water vapor to pass through? Under very humid conditions - such as in an extended rainstorm – does the bag’s down absorb some moisture? Does the bag readily dry out if it gets damp inside?

Durability—Is the bag’s shell fabric durable enough for normal backpacking conditions, i.e., does it snag or puncture easily? How does the bag hold up long-term under responsible but constant use? Does the bag lose any loft after repeated use and many stuffings? How does the stuff sack hold up, i.e., no failed seams?

Suitability For Ultralight Backpacking—The MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag is in the normal weight range for an ultralight 32 F (0 C) sleeping bag. Is its warmth and utility comparable with other bags in the same range?  How much can I extend its temperature range?

Acknowledgement
I would like to thank MontBell and the BackpackGearTest Group for selecting me to participate in this test.

Will Rietveld