The sleeping pad is just as important as the sleeping bag for keeping you warm. The sleeping pad you choose plays a big role in how well you sleep and how much space and weight it takes up in your pack. One tip is to also bring an inflatable pillow.
Based on what you will use the sleeping pad for, you need to make some choices:
The thickness determines how soft the sleeping pad is, but not necessarily how well it insulates against heat. A thicker sleeping pad has more air to warm up. For indoor overnight stays, a thicker sleeping pad is needed to achieve the same comfort as a thinner sleeping pad on soft forest ground.
Sleeping pads are available in several lengths and widths. Make sure you fit entirely on it. If you like to sleep on your back, you'll need a longer sleeping pad than if you usually sleep on your side. If you have a thick and fluffy sleeping bag, it will take up more space in width than a thin summer sleeping bag.
R-value indicates how well the sleeping pad insulates against cold. The higher the R-value, the more insulation. If you often feel cold on the underside of your body when sleeping outdoors, you need a warmer sleeping pad, not a warmer sleeping bag. The sleeping bag is compressed under your body, and that's where the sleeping pad does its job. A sleeping pad is never too warm, unlike a sleeping bag.
Summer +10 degrees Celsius, R-value 1-2
Spring and autumn 0 to 10 degrees Celsius, R-value 2-4
Spring, autumn, winter -10 to 0 degrees Celsius, R-value 4-6
Winter Colder than -10 degrees Celsius, R-value 6-8
An inflatable sleeping pad can offer the most comfort and also the highest insulation capacity. However, they can also take up more space in your pack and weigh a bit more. An inflatable sleeping pad is not the same thing as an air mattress. A sleeping pad can have materials that insulate against cold and channels that make it easier for the body to warm up the air.
An inflatable sleeping pad is inflated with a pump sack or pump. Avoid inflating it by mouth as moisture and bacteria can get inside. Inflatable sleeping pads can puncture, and then they lose all their heat retention capacity. Always make sure to bring a repair kit (included with several suppliers).
Advantages: soft, comfortable, warm, convenient pack size
Disadvantages: can puncture and then become cold, can be slightly heavier than self-inflating sleeping pads, must be inflated before use, usually the most expensive
Self-inflating sleeping pads usually have foam padding that makes them soft and insulating. They inflate by themselves when you open the valve. You can add air yourself if you want a firmer sleeping pad. They are light and easy to pack but are rarely as thick and comfortable as an inflatable sleeping pad.
A self-inflating sleeping pad can get a puncture, but it will still retain some of its insulating properties, unlike an inflatable one.
Pros: quite soft and warm, decent packed size, quick and easy to set up, mid-range price
Cons: can be punctured (but retains some insulating properties), medium weight
Closed-cell foam sleeping pads are sometimes called classic sleeping pads because they have been around significantly longer than air mattresses. They are lightweight and can be hung on the outside of a backpack to save space, as they do not add much weight to the pack.
A closed-cell foam sleeping pad is also perfect as extra insulation under an air mattress. It is also practical if the ground is sharp and uneven, as they do not break easily. Furthermore, they are much cheaper than inflatable versions.
Advantages: ready to use, lightweight, inexpensive, durable
Disadvantages: not soft, bulky, not very warm
