Manufacturer’s Website: www.bigagnes.com
Recommended 20″ x 72″ x 2.5″ Air Core Pad
The Big Agnes Horsethief is a mummy-shaped down sleeping bag with three distinctive features: no down under the sleeper, a sleeve on the bottom to hold a ground pad, and a built-in stow sack to create a fixed pillow by inserting clothing. Unlike its warmer brother, the +20 deg F Zirkel (also reviewed this issue), the Horsethief has no hood. Big Agnes rates this bag to +35 deg F for a moderate sleeper when paired with one of their ground pads. The bag’s pad sleeve will appeal to anyone who has ever awakened cold because they rolled off their pad during the night. The Horsethief has a feature usually only found in more expensive and warmer bags – a “no-draft” yoke. This is a down-filled collar that drapes down from the top of the bag and seals around your neck to prevent warm air from escaping and cold air from sneaking in.
Big Agnes’ 2.5-inch thick Air Core mummy pad is innovative for its lack of foam – at least in backpacking circles. Hey, people have been car camping and floating around the pool on these for years. But jesting aside, the Air Core mummy pad weighs about one-half to one-third the weight of a similar thickness foam-filled, self-inflating mattress. The pad is contoured to fit exactly into the pad pocket on the Horsethief. It took our staff 80-90 seconds to fully inflate the pad, and yes, we were a bit dizzy at the end.
The exterior shell is 30-denier Pertex nylon microfiber ripstop with a fluorocarbon DWR treatment for a windproof and water resistant shell. The interior lining is a soft and breathable 30-denier Pertex nylon microfiber. The bag bottom is a durable 210T DWR- treated ripstop nylon. The insulation is 775 down fill – the highest available quality. The bag is well sewn and the workmanship is fine with no obvious gaps. Given the high quality of materials and construction, we expect that the Horsethief will give years of service if cared for properly.
Our review staff made preliminary loft measurements of the Horsethief and compared them with bags of known field performance. Based on this comparison, we anticipate that, paired with a warm hood or balaclava, the Horsethief should work down to freezing, if not better, for many hikers (more in future issues on the field performance of this sleeping bag).
The attached pillow stuff sack is a nice idea. It solves the problem of chasing your slippery nylon “pillow” that has a life of its own as it pops out from underneath your head and scoots away during the night.
The Horsethief’s cut is roomy for a light mummy: a 67.5-inch girth compared to a Western Mountain Apache at 61 inches, and a Western Mountaineering UltraLite at 59 inches. Our larger and more restless sleepers liked the roomy cut — our medium build and quiet sleepers felt that it might be a bit drafty and a smidge more bag than they needed. The larger girth offers the option of wearing a jacket inside the bag to extend its range in cold weather.
Note: When you place the Air Core mummy pad in the pad pocket, the Horsethief loses some of its roominess. The rigid pad flattens out the bottom of the bag, reducing volume and making it feel tighter than its 67.5 inch girth. For this reason, some of our reviewers preferred sleeping with the pad outside of the pad pocket. The 20-inch wide Air Core pad is a bit narrow. The rounded edges of the pad make it seem closer to 18 inches wide. One of our mid-sized reviewers had problems keeping their arms from sliding off the pad. Still, the Air Core pad is the epitome cushy trail comfort.
The Horsethief and Air Core pad combination weighs about a half pound less than many light +30 deg F down bags paired with light, full-length, self-inflating pads (e.g. Marmot Arroyo and Thermarest Ultralight). However, the Horsethief alone weighs about half a pound more than minimalist sleeping bags like Nunatak Arc Alpinist or Rab Top Bag that have similar loft over the sleeper. The combination of the Horsethief and Air Core mummy pad weighs about pound more than a minimalist bag paired with a closed cell foam pad (e.g. Mt Washington), albeit the Big Agnes combo has more features and comfort.
The Big Agnes Horsethief is a high-quality bag with a lot of design innovations and creature comforts. It manages these while weighing less than many light down bags with similar temperature ratings. If you want to cut some weight but aren’t ready for the Spartan sleeping accommodations of minimalist bags, the Horsethief and an Air Core pad may be the right choice for you.