The Thermalite self-inflating mattress is light and does not require any extra equipment or energy on the part of the camper for inflation. However, novice users may be perplexed at first about how to deflate the mattress when they break camp and pack their gear. While deflating the mattress requires a bit more time and effort than inflating it, the process is relatively easy to learn.
Roll the mattress up quickly. Since the mattress is inflated, it will not roll readily. You may want to kneel on the pad as you roll it in order to force air out through the valve. Keep the valve open throughout this process.
Close the self-inflating valve. Do this while the mattress is still rolled up so no air can enter through the valve.
Unroll the sleeping pad to its full length again. You want the mattress to stay deflated so keep the valve closed.
Roll the Thermalite up another time. It will roll more easily this time because it has partially deflated. As you roll the mattress up, air will move toward the valve end forming a cushion of air.
Open the air valve again when you have rolled all but the last 10 inches of the sleeping pad. Continue to roll up the mattress, kneeling on the roll to squeeze out any last remaining pockets of air. With your weight still pressing on the Thermalite pad, re-close the valve.
If you have never used a self-inflating sleep pad before, do not expect it to expand to the same thickness as other camping mattresses. The thinness of the Thermalite makes it light enough to carry when your goal is maintaining a low weight for all your gear, as in backpacking or kayak camping. Once you have learnt the technique for deflating the mattress, you can try reducing its size still further by folding it in half lengthwise before you roll it for the second time.