Our testers hail from Bishop, California, and the Northeast United States. Both of these areas offer a perfect place to test cold weather sleeping bags. In the northeast, testers were able to get the negative degree temperatures needed to find the lower limit of some of these bags, while tester in the Sierra had a great time figuring out which sleeping bags were light enough to carry 9000ft up and everything in between! We spent countless chilly nights and bitter cold mornings burrowed in sleeping bags, rolling around searching for cold spots, tightening drawstrings, and snoozing hard. Testing occurred inside and outside of tents in a variety of weather conditions, from rain to brutal -20F nights.
These bags were tested by climbers, ski patrollers, serial road trippers, and dirtbags who have spent significant portions of their lives in sleeping bags in both professional and recreational settings. Guys and girls of different sizes spent time in each bag and weighed in on their favorite features, and what they loved and hated.
Spending several nights in each bag, our testers evaluated warmth by paying attention to cold spots, any signs heat loss around the draft colors, and by looking at loft height. We kept the manufacturer ratings in mind during our testing, but how warm we felt waking up in the morning was more of a deciding factor. Remember that some folks will tend to sleep cold, awhile others sleep warm. When considering a sleeping bag, it's important to "know thyself".
We weigh each bag on our scales to confirm manufacturer claims and consider what materials are adding to the bags' warmth and weather resistance, and which materials are just heavy and low quality. The manufacturers stated weights were not always as accurate as we had hoped, but understand that with consistent use, the bag gains weigh in terms of moisture and dirt and oils.
Our testers tossed and turned in these bags, attempting to sleep in a plethora of positions to determine comfort. Our testers ranged from petite 5'4" ladies weighing no more than 115lbs all the way up to 6'3" heavyweight guys weighing around 220lbs. Both of the extremes could have been better suited with short or tall sized sleeping bags, but we wanted to see how far we could stretch the regulars. In our specifications, we list as many size dimensions as we can.
We compressed each bag into the same compression sack to compare them as accurately as possible. We timed this process and while all the bags actually fit in our control compression sack, some took quite a while to stuff in there.
We looked at features in terms of quantity and quality, considering how useful each feature actually is. For example, If a bag has a draft collar, does it actually keep cold air out? Is it chronically getting stuck in the zipper? We found that not all features are created equally.
Second only to warmth, weather resistance is a very important consideration when purchasing a bag. We layed in the rain (and the sprinkler) to see if each bag leaked and where they are vulnerable to moisture. We also forced water in by holding the bags in a tub of water and looking at how much they absorbed. We gave bags with water-resistant down an extra point in this metric, but we couldn't get eyes on the down without damaging these very expensive bags.