Long Term Report:
MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag

Sleeping in the MontBell Ultralight Alpine Down Hugger #3 Sleeping Bag in a single-wall tent.

Summary
The Montbell Ultralight Alpine Down Hugger #3 is a “mixed bag”, so to speak. At 21.2 ounces (600 g), it is definitely light for a 32 F (0 C) rated bag. And that weight includes several useful features, like a full-length zipper, drawcord at the foot, and a well-proportioned hood. Its lightweight Ballistic Airlight shell fabric is soft, downproof, and very water-resistant. However, the bag has only 2 in (5 cm) of single layer loft and is chilly to sleep in when the temperature drops to near its temperature rating. In my opinion, the bag needs a little more down or higher lofting down, to bring it to its claimed temperature rating.

Product Information
Manufacturer: 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 for user height to 70 in (178 cm) , Long for 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 or 0.1 g)
Fill Weight: 10.6 oz (301 g)
Stuff Sack Weight: 0.85 oz (24 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 (information 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

Test Description
Test Period—Mid-April to September 2006.

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

Testing Conditions—The testing environments consisted of: canyon country, forests, and alpine terrains. Elevations ranged from 5000 to 12,500 feet (1524 to 3810 m). Extreme conditions included: strong winds, dust/rain storms, heavy rain, low temperatures, and high elevations with intense thunderstorms. I tested the bag at temperatures both above and below its temperature rating, and in wet and dry conditions. Nighttime temperatures ranged from 22 to 65 F (-5.6 to 18 C).

Type of Use—The Montbell Ultralight Alpine Down Hugger #3 Sleeping Bag was tested while backpacking. The shelters I slept in were a single-wall tent, a poncho-tarp, and a double-wall tent.

Amount Of Use—During four months of testing I have used the Montbell Ultralight Alpine Down Hugger #3 Sleeping Bag on 14 backpacking trips totaling 42 days (28 nights) and two car camping trips totaling 4 days (2 nights).

The Montbell Ultralight Alpine Down Hugger #3 Sleeping Bag was mainly used as part of an ultralight backpacking system including a plastic groundsheet, torso-length sleeping pad, and poncho-tarp type shelter (Six Moon Designs Gatewood Cape).

Data—On each trip I recorded 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.

Evaluation
My four-month evaluation of the Montbell Ultralight Alpine Down Hugger #3 Sleeping Bag is broken down into ten specific factors.

Materials, Quality, and Construction—The Ballistic Airlight^™ hollow fiber calendared nylon shell is really impressive. It’s very lightweight and has a soft feel, yet is durable and downproof. I looked over the quality of the sewing details, and found that it is very well made. Calendering is a heat treatment that strengthens the nylon fabric (similar to tempering steel), but it also makes it less breathable.

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 slept in the bag while wearing either a down jacket or a synthetic jacket and found the girth ample to accommodate extra clothing. I did not experience any down compression from the bag being too tight.

Features—Although this is an ultralight sleeping bag, it still has several useful features: 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.

The Montbell Ultralight Alpine Down Hugger #3 Sleeping Bag has a drawcord at the foot end to allow adjustment to the user’s height and to allow the user to create a “bootie” around the feet for extra warmth.

Usability—The horizontal seams have an elastic stitching that causes the bag to contract and hug my body when I am inside. The bag easily expanded to accommodate my movements inside the bag, and it did not inhibit my movements in any way.

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 such a small sack, and then there is a second drawcord provided to compress 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. After using the provided stuff sack a few times, I refused to use it any longer for fear of damaging the sleeping bag. Henceforth I used a larger stuff sack that the bag more easily packed into (however it did take up more space in my backpack).

The shoulder girth of this bag expands to 64 inches (163 cm), which is very roomy and provided 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.

The full-length zipper operates fairly smoothly for getting in and out of the bag. It easily snags on the shell fabric (especially on some labels midway), but no more than other ultralight bags I have used. There is a small Velcro tab at the top of the zipper to keep the zipper from opening from my body movements. However, I found on many occasions (especially when wearing an insulated jacket inside the bag) that the tab does not hold and the zipper opened when I turned over. It helped to squeeze the tab to make the Velcro grip better.

I personally feel that a full-length zipper is overkill on an ultralight sleeping bag. For my backpacking conditions (western mountain and desert camping, usually in cool weather) I would be perfectly happy with a half-length zipper or no zipper. However, on one warmer 65 F (18 C) night I completely unzipped the sleeping bag and used it as a quilt. I also did not find the drawcord at the foot end of the bag to be very useful. I normally wore wool socks inside the bag, which was sufficient.

The hood is ample sized and covered my face down to my mouth when drawn, so it kept my face warm. There is plenty of room inside to accommodate wearing a warm hat. The drawcord does not operate as smoothly as I would like. I suggest using a slightly smaller diameter and smoother cord for the micro-cordlock that is used.

Insulation And Loft—When the bag was new I measured its loft by thoroughly shaking the bag vertically and horizontally, then laying 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 was approximately two inches (5 cm).

I repeated the loft measurement (using the same procedure) at the end of the four-month test to see if the bag’s loft had changed from my use. I could not detect any change in loft.

With only 10.6 ounces (301 g) of down (for size Long) and 2 inches (5 cm) of loft, in my opinion, the temperature rating of this bag is somewhat optimistic. The bag has vertical baffles to hold the down in place, so it does not have any capability to re-distribute the down (as with continuous baffles) to increase the loft on top. When I held the bag up in front of a strong light I discovered that several compartments (especially in the torso area) contained very little down. In my opinion, this bag would benefit significantly from the addition of another ounce (28 g) of down, or higher lofting down. For an expensive ultralight sleeping bag, 725 fill-power down is low by today’s standards. Montbell plans to upgrade to 800-fill power down in their sleeping bags in 2007, however it is uncertain if the amount (weight) of down in the bag will remain the same.

With the bag in front of a strong light, several areas of minimal (or no) insulation are visible.

When I weighed the bag, I found it to be 0.85 oz (24 g) lower than specified, and reported in my Initial Report that it was underweight. I subsequently figured out that the stuff sack weighs exactly 0.85 ounces (24 g), so I conclude that the manufacturer’s specified weight is the weight of the bag plus the stuff sack.
 
Comfort and Warmth—In the field, I slept in the Montbell Ultralight Alpine Down Hugger #3 on 16 backpacking and car camping trips, for a total of 46 days and 30 nights. Temperatures ranged from 22 to 65 F (-5.6 to 18 C), with four nights  with lows of 22, 28, 29, and 30 F (-5.6 to -1 C), below the bag’s 32 F (0 C) temperature rating.

While sleeping in a well-ventilated shelter I found the bag to be warm (for me) down to about 38-40 F (3-4 C), while wearing long johns and a warm cap inside the bag. On cooler nights down to freezing I was chilly below about 38 F (3C) and found it necessary to also wear a synthetic insulated jacket and pants inside the bag. On the coldest night I wore a down insulated jacket and pants inside the bag to stay warm. I am generally a warm sleeper, meaning I don’t get cold easily.

I found the bag seals up very well to trap heat, and did not detect any drafts around the zipper or hood. The thinly insulated areas in the torso area contributed to an overall chilly feeling when the temperature dropped below 38-40 F (3-4 C). From my experience over four months of use, I conclude that the Montbell Ultralight Alpine Down Hugger #3’s minimum comfortable temperature (for me) is around 40 F (4 C), and that the bag is overrated by about 8 degrees F (4 degrees C). However, as I noted above, because of the bag’s roominess, it is easy to wear additional insulated clothing inside the bag to extend its warmth down to about 25 F (-4 C) or so.

Water Resistance—The bag’s shell fabric has a Durable Water Repellent (DWR) treatment that really repels water. I put some water in a small depression on the bag and let it stand for an hour and it did not soak through. However, the seams are not seam sealed, so water will soak through the stitching.

On several backpacking trips, it rained in the evening, then cleared overnight allowing the temperature to drop to freezing (32 F or 0 C) or below. I had lots of frost on the outside and inside of my shelter (especially the single wall tent and poncho-tarp), and the Montbell bag was quite damp on the outside. One another occasion I slept in a tent that leaked badly during a rainstorm, which resulted in puddles of water in the tent and on the bag. On another occasion a nighttime thunderstorm blew rain in from the open side of my Gatewood Cape. The rain hit the backside of the sleeping bag and drained down on my sleeping pad. In the morning I was sleeping in a puddle of water. In all cases the bag’s surface DWR treatment did a superb job of keeping the moisture from soaking into the bag. The bag retained its loft and I stayed warm.

Breathability—In spite of its calendaring, the shell fabric appears to be adequately breathable to allow moisture to pass out of the bag in response to the thermal gradient created from my body heat. I did not detect any tendency for the bag to accumulate moisture under high humidity conditions. However, periods of wet weather were followed by periods of dry weather, so there were ample opportunities for the bag to dry out.

Durability—I found the bag’s shell fabric to be adequately durable for normal backpacking conditions, with no snags or punctures whatsoever. I have repeatedly stuffed the bag in a stuff sack and its loft springs back to original proportions each time. The shell fabric is also very downproof; I had very few instances of down penetrating the shell.

Suitability For Ultralight Backpacking—The Montbell Ultralight Alpine Down Hugger #3 at 21.2 oz (600 g) is definitely compatible with ultralight backpacking. It is roomy enough to wear additional clothing inside to extend its warmth. However, I would readily give up the full-length zipper in exchange for an extra ounce of down. Also, I would prefer a higher grade of down (800 fill power) for a high-end ultralight sleeping bag.

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

Will Rietveld