The Basic Guide to Backpacking Sleeping Pads

Sleeping pads come in different sizes, shapes, materials and fill. The range of products available is bewildering and the possibilities are endless. While it is not practical to carry the big puffy air mattress used in car camping, the level of comfort afforded by that air mattress can be replaced with todays backpacking air mattresses and pads. It is possible to get a self-inflating pad, an air mattress or a foam pad. In looking for a pad, much of the decision rests on personal comfort and anticipated weather conditions. It will not be a comfortable night if you use a summer pad for winter camping. An uncomfortable pad will also deny you the rest you need after a long day of hiking.

The first thing to consider is fill material. Sleeping on the ground can leech a lot of heat from your body if the pad can't contain your body heat. Sleeping pads like sleeping bags come with temperature ratings, mostly in the form of an R value. The R value measures the pad's resistance to heat loss. The greater the R value the less heat will be lost and the warmer you will stay. Pads come in various fill types and each type has a different R value.

Closed Cell Foam
Closed cell foam is a hard foam with tiny air pockets. Closed cell foam can be a great pad due to its puncture resistant nature. The draw back is that closed cell foam is hard and doesn't compress well. While the closed cell foam is not a great absorber of water, it also doesn't compress well and can take up a lot of space even when stored. The Therm-a-Rest Z Lite is a good example of a closed cell pad and retails for $35.

Open Cell Foam
Open cell foam is made of a lighter airier material then closed cell foam and as such requires more thickness to get the same level of protection. While the foam is more comfortable, it is also possible for it to hold and retain water like a sponge. Open cell foam can be used as is, but as a backpacking pad, open cell foam is generally contained between two layers of protective material to prevent water absorption. As this also keeps air contained within the foam, less foam is needed to get a comparable level of comfort. This setup leads to a 'self inflating' pad, when the air valve is opened, the foam expands and air rushes in to fill the void, although it is necessary to add a little more air to get optimal comfort. Puncturing can be an issue but with careful site choice, this can be kept to a minimum. The Therm-a-Rest Ridge Rest is a good example of a self-inflating pad and retails for $45.

Air mattresses
While not exactly a pad, air mattresses have come a long way. They are small and light enough for one person to carry and use on a long distance trek. Air alone is not a very good insulator and an uninsulated air mattress has a very low R value, as there is nothing to prevent the loss of heat. These are best for summer or 3 season platform use. Big Agnes' Air Core pad is a good example of a non-insulated pad, it retails starting at $45. An insulated air mattress has a much better rating depending on the fill type. The fill can be either down, or open cell foam. These can work through 4 seasons depending on the winter temperatures and the R value. While punctures can be an issue, with a good ground sheet and careful site location, this can be kept to a minimum. Pacific Outdoor Equipment's InsulMat is a good example of a foam fill, retailing for $70 (the uninsulated version retails for $43). The Exped Downmat is a good example of a down filled mat and retails for $150.

The next thing to consider is size. Most pads come in either regular/tall or 3/4. The advantage to a regular/tall sized pad is that you are kept off the ground from your head to your toes. In winter, it is very important to stay off the ground as it is harder to warm up once you are cold. Depending on the type of pad and how tall you are, that extra length can add up to extra weight. This is where the 3/4 length pad comes into play. These pads work best in combination with a backpack placed under the foot section of the sleeping bag where the pad ends. This keeps the feet and legs off the ground while using something you are already carrying. Since legs and feet do not require as much padding, this can be relatively comfortable.

Shape is the final consideration. Just as bags come in several basic shapes, so too do pads. Pads can come in mummy or rectangular shapes. The shape of the pad is rather trivial. A mummy pad weighs less, but you have a greater chance of legs falling off. A rectangular pad weighs a bit more but you have a greater area on which to stay. The only time it is very important to pay attention to the shape of the pad is if your sleeping bag comes with a pad pocket or pad slot as the pad needs to fit into that space.

For summer use, an uninsulated air mattress, self-inflating pad, or foam mat will work best without causing you to be overly warm. If you anticipate using tent platforms or shelters, these same pads can be used earlier and later in the season where normally they would be cold on bare ground. Cold season use will require something with more insulation but depends on the types of conditions expected. Further south might only require an insulated air-mattress or even a slightly thicker self-inflating pad or foam mat. Further north or at high elevations will require something will a good amount of insulation. Down mats and doubling up on pads will help with preventing heat loss. It is possible to carry a light weight summer pad and a light weight winter pad and combine them for heavy winter use. It is best to put the insulated mat against the ground to prevent heat loss. Doubling up gives much more flexibility with gear as each pad will have its uses (insulated in spring and fall, uninsulated in summer) and together will extend the season into winter.

Choosing a pad is an important decision. Just like a bed mattress, it is important to try the pad out in the store. Lay down on the pad as you would if you were trying to sleep. If you are a side sleeper, it is very important to try laying on your side as the greatest points of contact will be your hips and shoulders. If the pad is going to be used more for winter camping, make sure all your contact points are nicely supported and there is little contact with the ground. Any ground contact will be a potential cold spot later. Different sleep systems will will make different demands on what will work underneath as a pad. In a hammock, it can be hard to keep firm pads underneath, and in some weather pads are not really needed. Consider what will best fit in your pack. Some pads pack down very small while others don't pack down much at all, like closed cell foam.

The right pad makes all the difference in the world on overnight or longer trips. Try not to compromise on comfort as a good nights sleep is worth every penny and ounce, especially on long distance trips. I have used an InsulMat for several years now and have been in love with it ever since I first used it. This is the closed thing to my bed that I can get while away from home. While puncturing can be a concern, I have not yet had any issues with a puncture in my mat.