Most will agree that a good night’s sleep in the hills makes the subsequent waking hours more enjoyable and productive, and that a comfortable sleeping pad plays an important role in this process. However, the various designs and preferences in sleeping pads result in a number of ways to arrive at what each person deems a comfortable arrangement. More important than physical cushioning is the resistance they provide that reduces heat conduction away from your body. There are two broad categories of sleeping pads discussed below: closed cell foam, and inflatable.
Closed Cell Foam
These are traditionally the most common and historically the first effective true backcountry sleeping pads. High foam density is key for warmth, and some products offer a “bubbled” or “ridged” design to increase efficiency. Unfortunately the depressions can also gather snow and water.
These pads have a number of benefits compared other designs. They are light (approximately 5-16 oz. depending on thickness and length), inexpensive, and can be literally ripped in half and still function as designed. They offer a degree of safety in their durability, which should not be over-looked.
I will mention backpack back pads here because despite not being a designed sleeping pad, mountaineers and other mountain athletes have been using them as such for years. A pack whose frame can be removed or lies relatively flat can be placed under a lighter pad (or simply the user if no other pad is employed) to increase insulation. Focusing on the shoulder and hip areas, a great deal of added warmth can be attributed to this technique. Even the body of a pack without a pad is beneficial.
At the very least, the use of a pack in conjunction with a sleeping pad can allow you to use a thinner pad, a shorter pad (by putting the pack at your feet), or an inflatable pad without as much concern about failure.
Most consider inflatable pads far superior in terms of comfort. One of the most popular designs is based on the original Thermarest self inflating mattress, with foam cut in various designs and thicknesses to tweak weight and bulk. It then “self-inflates”, the valve is closed, and support is provided. These pads can be effective for warm to cool temperatures, and are marginally adequate in and of themselves for use in cold temperatures. The places where the foam has been removed to save weight draw warmth from the body, and a thickness of 1”-1.5” of low density foam is not sufficient.
Another popular inflatable construction is the vertical baffle seen in Big Agnes pads like the Insulated Air Core. They can be filled with synthetic insulation or down in order to maximize resistance, and are often 2.5”-3” thick, providing incredible comfort for the weight. The best insulated models are sufficient for the coldest temperatures.
Worth noting is the horizontal baffle design used by Thermarest in their Neo Air model. By using baffle design instead of insulation to provide thermal resistance, it offers 3-4 season warmth and excellent comfort for under a pound. Both of these designs must be inflated by blowing into a valve, adding a small level of inconvenience (the level of inconvenience is directly correlated to your current level of exhaustion).
Unfortunately, inflatable pads have some drawbacks. They are generally more expensive than their closed cell counterparts, are slightly heavier, and can be rendered useless if a puncture cannot be repaired effectively. Because a severe puncture could mean disaster for an inflatable pad, sturdy fabrics are beneficial if any abrasion is to be expected.
Some have taken to using an ultra light inflatable pad and very thin closed cell foam pad together, providing a good deal of insulation and redundancy. To function most efficiently, the closed cell pad should be placed on top of the inflatable. Using this method, you can still come in under a pound for your pad system.