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Reviews > Sleep Gear > Sleeping Bags > Big Agnes Grouse Mountain 15 Mens Bag > Test Report by Mark Thompson

May 08, 2012



NAME: Mark Thompson
EMAIL: markthompson 242 at gmail dot com
AGE: 47
LOCATION: Parker, Colorado, USA
HEIGHT: 6' 0" (2.10 m)
WEIGHT: 190 lb (86.20 kg)

Outdoor adventures started for me at an early age, my passions have grown to include backpacking, rock climbing, hiking, hunting, fishing, canoeing, cycling, skiing and snowshoeing. Most of my adventures presently take place in Colorado's amazing Rocky Mountains. For trail hikes, my pack typically weighs 15 lbs/7 kg (summer/fall), 25 lbs/11 kg (winter/spring) and trail speed ranges from 2.5 - 4 mph (4 - 6 km/h) depending on elevation gain. For backpack trips, my pack weighs 40 - 45 lbs (18 - 20 kg) and my trail speed drops to 1.5 - 3.0 mph (2 - 5 km/h).



Manufacturer: Big Agnes
Year of Manufacture: 2011
Manufacturer's Website:

Sleeping Bag Only:
Size: Long
MSRP: US $249.95
Listed Weight: 3 lb 6 oz (1.5 kg)
Measured Weight: 3 lb 4 oz (1.47 kg)

Sleeping Pad:
Size: Long (78 in x 20 in x 2.5 in / 198 cm x 51 cm x 6.4 cm)
MSRP: US $84.95
Listed Weight: 27 oz (765 g)
Measured Weight: 31 oz (873 g)

Sleep System Total:
MSRP: US $ 334.90
Listed weight: 5 lb 1 oz (2.3 kg)
Measured Weight: 5 lb 1 oz (2.3 g)

Top view of assembled sleep system
Bottom view of assembled sleep system

Additional information from manufacturer's web site:

Sleeping Bag
- Integrated half pad sleeve:
o unique design keeps you securely attached to the pad from the hips up
with adjustable strap holds ANY 20" wide rectangular or mummy shaped pad
- No-draft wedge insulates the connection between the bag and the pad
- Pad sleeve: Nylon rip-stop. WR surface treatment to repel water
- Mummy shape decreases weight & packed size
- Cotton storage sack & nylon stuff sack included
- Built in pillow pocket holds a fleece or Big Agnes pillow
- Interior fabric loops for sleeping bag liners
- 70" YKK #8 zipper. Mate together any of our left and right zip bags with the same size zipper
- No-draft collar seals around neck to keep cold air from sneaking in
- No-draft zipper tube insulates along the length of the zipper
- Shell: Down proof, nylon microfiber rip-stop. WR surface treatment to repel water
- Lining: Soft, breathable down proof nylon with stain resistant finish
- Flow™ Construction: Insotect Flow™ is a flow-optimized insulation system that delivers uniform heat distribution and natural body contouring through its revolutionary baffle design. Flow Construction eliminates lateral and vertical down shifting by using vertical chambers with Flow Gates to regulate fill positioning and density. Strategically placed Flow Gates minimize vertical down shifting while vertical chambers minimize lateral shifting. With continuous vertical Flow chambers in place of traditional side seams, Flow bags eliminate potential cold spots which can occur with side seams. Vertical baffles now flow with your body for more rapid and uniform body heat distribution.

Sleeping Pad
- Light and compact three season pad, with 2.5" of comfort
- PrimaLoft™ eco: synthetic insulation made from 50% recycled materials used in all 20" wide pads
- I-beam construction eliminates welded seams to reduce cold spots and ensures quick inflation/deflation, consistent air flow and stability
- 20" pads: Durable, lightweight 50D nylon diamond rip-stop top and bottom
- Internal polyurethane coating
- Add a closed cell foam pad in colder temperatures for extra insulation
- Non-breakable brass valve with plastic coated EZ-Flate™ mouthpiece
- Store unrolled with valve open
- Includes stuff sack and repair kit. The repair kit is in a small pocket on the inside of the stuff sack. It's sort of hidden, so look twice!
- Each pad individually inflated and tested
- EZ-Flate Valve instructions: Twist black part of valve counter-clockwise to open. Blow into valve to inflate. Hold gray portion of valve in mouth while spinning black portion clockwise to close.


Since the sleeping system is the result of integrating a sleeping bag and a pad, I will cover the two pieces separately first, then cover the pieces together.

The sleeping bag presents some very unique features, and, quite honestly, a shift in paradigm when it comes to back-country sleeping.
First and foremost, Big Agnes eliminates insulation on a portion of the bottom side of the bag. The thought being that the insulating material will be compressed under the weight of the user and thus, provides little to no benefit.
To ensure warmth, the pad becomes the source of insulation.
This bag is also equipped with a rather significant insulated collar (something I typically find in sleeping bags with lower temperature ratings) and what amounts to a built in pillow case. I typically stuff some soft clothes into the sleeping bag stuff sack (a trick I learned from an old mountaineer) so this will be something new for me. The pillow case is filled from the back side with an overlapping pocket design. When folded back into the bag, the seams are in the back. Along the side, the bag features a nice long zipper which allows for easy access and lots of temperature control. Another feature of the zipper is that it full separates allowing bags with compatible zippers to be zipped together. The zipper length is common between the regular and long size bags as well. This may or may not appeal to some, but this is a great feature to get someone warm or if the temperature drops below the comfort range, and we all know how accurate meteorologists are.
I did note that there doesn't appear to be a significant amount of loft, certainly not as much as I would have expected when using 600 fill down. I will certainly find out when I take this out into the field (although, my wife offered to let me sleep on the porch - not sure what prompted that).

The sleeping pad is of the manual inflating variety, meaning that some of my hot air will have to go to use. The valve system is a combination of brass and plastic and the instructions provided are fairly clear on how to use the valve so all the doesn't escape. The pad is rather heavy, but provides a new level of comfort when compared to the thin closed cell foam pads I have used in the past. Honestly, I bought this very pad over a year ago and have never regretted the extra weight. The pad is black on one side and maroon on the other.
Inside the pad are fibers that somehow hang from the maroon side of the pad, which is the source of the insulating power of the pad. During the summer, the pad can be used with the black side up which decreases the effectiveness of the insulation and thus a cooler night's sleep. Although not well advertised, Big Agnes does recommend that the pad be stored unrolled.

After I assembled the two together, I was rather impressed at how snugly they fit together. When I first read of the Big Agnes system some time ago, I thought that keeping the two together would be like trying to hold a beach ball under water. It looks like a solid design and I am excited to see how well this actually performs in the field. Laying on the kitchen floor, the bag does appear to be slightly longer than the pad, but I expect that this will not be the case with a body inside. I typically like to stretch out and take up more length than my height would normally require, but at 72" (1.83 m) I am technically 6" (15 cm) shorter than the pad, which should allow for some room for a pillow and a water bottle or two.



The bag appears to be very well designed and constructed. The absence of loose feathers and hanging threads was pleasant, but not a surprise.

- This bag presents a neat philosophy, integrating the bag and pad as a sleeping system
- Cool features:
- Well designed collar
- Integrated pillow case
- Integrated pad
- Comfort

- The sleep system is a little heavy
- I don't yet see a way to reduce weight and maintain the integrity of the system
- The pocket and strap that hold the pad in place do not appear to be adaptable to other, lighter pads



Since receiving the Big Agnes Grouse Mountain 15, I have tested the sleep system on two "hut" trips, two backpacking trips and one unplanned overnight in the back of my Suburban for a total of 5 nights of use. All of these were within the colorful State of Colorado and were very mild winter conditions. Much of this winter has, however, been extremely cold and well below the rated capacity of the system. Being that I am a cold sleeper I had to carefully select the times and places where I could effectively test the system. I have also utilized the pad on several other trips in conjunction with lower rated bags. For extremely cold nights I added a ¾ length closed cell foam pad for added insulation. Below are the trips where temperature and events provided the greatest opportunity to perform testing of the complete system:

Location: Pike National Forest
Date: 23 - 24 March 2012
Elevation: 7,600 ft (2,316 m)
Product usage inclusive: one night
Weather: clear, low of 24 deg F (-4 deg C)

Location: Grouse Canyon, Chaffee County, CO
Date: 30 - 31 March 2012
Elevation: 9,100 ft (2,774 m)
Product usage inclusive: one night
Weather: clear, cool, low of 29 deg F (-2 deg C)


The Big Agnes sleep system represents a significant paradigm shift when it comes to backcountry sleeping. Every other sleeping bag I have ever owned required a separate pad to provide ground insulation and I don't ever recall the pad being made specifically for a particular bag or even by the same company. The integration of the bag and pad into a "system" is certainly unique and provides some intriguing benefits as well as some sleeping adjustments.

The weight of sleeping bag is significantly reduced due to the lack of insulation on the bottom of the bag, however, the weight of the overall system is greater than a closed cell foam pad and a sleeping bag with a similar temperature rating. The big difference here though, is comfort. The 2.5 inch (6.35 cm) manually inflated pad brings a new level of comfort compared to standard closed cell foam, and for me, it is worth every gram! The old style of air mattresses did provide improvements in comfort, but were heavy, prone to leaking and did not provide any ground insulation. The Big Agnes pad is miles ahead, with a high quality manufacturing process using solid design, resulting in a high performance pad at a realistic weight for backpacking. The sleeping bag is also much smaller than other bags so it fits much better inside of internal frame packs and provides a smaller profile on external frame packs.


I found the system to be quite easy to set up requiring less than a minute more than a separate bag and manually inflatable pad. Once set up, I found the system to be secure throughout each night of use and never encountered a situation where the two became twisted or required any evening maintenance.


As I mentioned early, I am a cold sleeper and I typically add 10 to 15 degrees F (5 to 8 deg C) to the rating of any sleeping bag. I found this to be true with the Big Agnes Grouse Mountain 15 as well. On my trip in the Pike National Forest, the overnight low was 24 deg F (-4 deg C) and I was just a bit cold, which is consistent with my experiences with other sleeping bags. I merely added a layer and went back to sleep.

Earlier, I mentioned that this system does require some adjustments in sleep patterns. The two things I noticed were: 1) I would have to roll inside the bag rather than having the bag roll with me and 2) the only way to obtain the full temperature rating of the system is by sleeping on my back (as opposed to sleeping on my side) as the integrated system keeps the facial opening directly up rather than allowing it to roll with me. Essentially, I would end up with my ear in the opening and breathing into the side of the bag when I rolled to one side or the other. I found that I was able to adjust to this by wearing a fleece balaclava and not cinching the face drawstring down as much. The neck collar was still effective in keeping the cold air from drifting down into the bag.


The Big Agnes sleep system is truly unique. When I was younger, I could find a way to sleep comfortably on just about any surface, but as I age, this is no longer the case and I find myself striving for comfort! The Big Agnes sleeping pad is super comfortable and insulated! In summary:
- Great weight to comfort ratio
- Secure and well designed
- Not as warm or comfortable when sleeping on my side



Since my Field Report, I have been on two more backpacking trips, totaling 7 nights and 12 days of use throughout the test period. Most notably was an overnight adventure in Herman Gulch, near Loveland Pass, Colorado. We packed in and set up camp to make for an early start and summit attempt of Citadel Peak.

Location: Herman Gulch
Date: 29 - 30 April 2012
Elevation: 11,000 ft (3,353 m)
Product usage inclusive: one night
Weather: clear, low of 17 deg F (-8 deg C)


My experiences with the sleep system during the Long Term Reporting period were very consistent with those in the Field Reporting period. As mentioned, earlier, I do tend to be a cold sleeper and typically need to add 10 to 15 deg F (5 to 9 deg C) to a sleeping bag's rating. What I did find of note during this reporting period was related to heat loss. On the Herman Gulch trip, the outside air temperature reached a low of approximately 17 deg F (-8 deg C) while the inside of the tent only dropped to 24 deg F (-4.5 deg C). Okay, no surprise there, but I noticed during the night that I was becoming cold due to heat loss through the pad. I suppose this makes sense as the snow temperature would not change based upon the temperature inside the tent, but I did find it interesting. To overcome the heat loss, I donned my down sweater and lined the bottom (inside) of the sleeping bag with my down pants.

I did become more familiar and thus more comfortable with the integration of the sleeping pad and sleeping bag. At first it did seem a little awkward, but after a few more uses I became much more comfortable and enjoyed the fact that I didn't slide off my pad during the night.


Big Agnes has clearly lived up to their motto "The Mother of Comfort" with the Grouse Mountain sleep system. My summary comments from the Field Report remain:
- Great weight to comfort ratio
- Secure and well designed
- Not as warm or comfortable when sleeping on my side

A special thank you to Big Agnes and for allowing me to test this fine piece of gear. After testing this sleep system, I had to buy the King Solomon!

This report was created with the Report Writer Version 1. Copyright 2012. All rights reserved.

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