Gear Post | 3 | Sleeping Pt. 1
“The woods are lovely, dark and deep. But I have promises to keep, and miles to go before I sleep.”
First off...what a hiatus...
Between finishing AmeriCorps, moving, working, procrastinating, sleeping, and eating, I really dropped the ball on this.
Anyway, despite not posting to the blog, my research never stopped. Today, I'm going to be covering a part of my sleeping system, the sleeping bag/quilt and the ground pad. Both are crucial to staying warm outdoors.
The sleeping bag/quilt and pad work in conjunction to reduce heat loss and trap heat inside. Looking back to freshman physics (which I may have been sleeping in), heat is lost through 4 main channels: conduction, convection, radiation, and evaporation. The ultimate goal of any sleep system is to keep the warm stuff warm, and the cold stuff cold. Contact with cold ground saps heat through conduction. A pad will keep the body off of the ground and away from the cold ground. The sleeping bag, or quilt in my case, minimizes heat loss through convection, radiation, and evaporation. The quilt prevents cool air from puling heat away from the body though convection. It also traps radiated heat and holds it inside, and finally minimizes evaporation from the skin. The goal of any sleeping system is to trap air and keep it as a buffer between a warm body and the cool outdoors.
The Enlightened Equipment (EE) Enigma, a lightweight, down quilt.
So, what's the difference between a quilt and a mummy style sleeping bag? Will I'm glad you asked! Well, let's start with the familiar. A mummy style sleeping bag continues up past the head, zips tightly closed (usually leaving just the face exposed), and like quilts, comes in many sizes, shapes, weights, and ratings. The primary difference between the two is the lack of insulation on the bottom. The theory is that due to the weight of the person inside, the insulation on the bottom of the bag is merely wasted due to compression of the fill. Therefore, designers sought to remove the bottom, save weight, and reduce material. In either case, a ground pad is present to reduce heat loss through the bottom.
In addition, the quilt ends at the neck and leaves the bottom of the bag nearly open. Clasps and straps allow the bottom of the quilt to be closed as desired. Although the quilt provides less insulation around the neck and head, this can be supplemented by warm caps or clothing. Nothing will replace a good mummy bag in the winter, but for 3.5 season camping, it should more than suffice.
The next thing I considered was down fill vs synthetic. Synthetic bags rely on spun materials like polyester to provide loft. Synthetic is a phenomenal insulator, even when wet, but is terribly heavy and packs down poorly. Down is ridiculously light, packs down to a fraction of its lofted size, but is completely useless when wet. In addition, down can lose loft (and therefore warmth) when dirty (sweat, dirt, oils, etc.) Despite this, down is the obvious choice due to it's weight and packability.
Down is measured in Fill Power, which is a measure of a down's loft (or ability to trap air). A down with a higher fill power will loft more than a down with less fill power with the same amount of total down. A higher fill power means having the same warmth with better compressibility and lighter weight than a down with less fill power.
The quilt. I chose the Enlightened Equipment Enigma for a few reasons. I wanted a quilt with minimal weight, down-fill, and able to be highly customized. The Enigma comes with three choices of down fill, down treatment, temperature ratings, length, width, and many colors. For my trip, I chose 850 fill treated down, 20 F rating, regular length, wide width, and some funky colors.
The Therm-a-rest NeoAir XLite
Just like the insulation in your home, different ground pads have different R-values. R-value is a material's resistance to conductive heat flow (in this case, loss). The TaR NeoAir Xlite has an R-value of 3.2, moderate on the scale in terms of pads. Some pads have R-values >6, but are significantly heavier and overkill for the AT. This model gains its R-value from from trapping air. Other models may use foam or a combination of the two. In addition, the thickness of the pad provides a nice reprise from the hard ground.
There's nothing worse than being terribly cold when sleeping, as many of my AmeriCorps friends can attest to while using those terrible sleeping bags.