How to choose a sleeping mat on the market?

Sleeping mats (commonly known as "moisture-proof mats" by domestic mountain friends) have become indispensable equipment for outdoor activities in the sense of isolating the cold earth. Compared with the beds at home, they are lighter in weight and easy to pack, making them suitable for outdoor people.
There is no doubt about the necessity of sleeping mats, tents, and sleeping bags to form three-piece sleeping mats that are indispensable to the sleep system. There are so many sleeping mats on the market, how should I evaluate them and choose the best? The first consideration should be the main mission of the sleeping pad-keeping warm 01 R value: the most important warm index R value is an important parameter used by many sleeping bag manufacturers to show the warmth retention ability of their sleeping pads. The R value, namely R-Value, is named after the R of the English phrase Thermal Resistance (heat isolation). It is used to measure the ability of an object to insulate heat conduction. The higher the R value, the stronger the heat insulation ability. The R value is a universal scale used in the material industry, not exclusive to outdoor use.
Speaking of the R value of the sleeping mat, if it is low, you will need to spend more energy to maintain body temperature if you sleep on it. As a result, you will wake up tired the next day and do nothing, because everything you eat is produced. The heat is gone. On the contrary, if the R value of the sleeping pad is in place, you can save precious calories and use it for high-intensity outdoor sports the next day. Generally speaking, in autumn and winter, when the temperature is slightly lower than 0℃, the R value of the sleeping pad should not be lower than 3. For extreme high-altitude and high-cold camping environments, the R value should be close to or higher than 5. For other warmer environments, the R value can be above 2 (data source: comprehensively compiled from the R value temperature scale of major sleeping bag manufacturers) R value is the most important indicator when we buy sleeping mats online, but what is more embarrassing is that each manufacturer’s There is no uniform method for R value measurement. Major manufacturers have their own test schemes that are fairly fair, while some manufacturers use somatosensory estimation, and some manufacturers do not even provide R value references. Therefore, to investigate the thermal performance of sleeping pads, we need to know more before directly referring to the R value given by the manufacturer.
Three categories of sleeping mats
To realize the isolation of heat conduction and increase the R value, there is a common practice all over the world: lock the air. Although flowing air takes away heat, still air is an excellent "material" for thermal resistance. Why is down material so warm? Because there are countless small air sacs between the velvet flowers. The design idea of ​​the sleeping pad is the same: lock the air. Based on this, there are three types of sleeping mats on the market:
Foam cushion-keep warm through countless small airbags inside the dense closed-cell foam material.
Inflatable cushion-artificially construct an air bag and fill it with air to keep warm. Some models will fill the airbag with other insulation materials to further enhance the thermal performance.
Self inflatable mats-a combination of foam cushion and inflatable cushion, using the expansion of open-cell foam to achieve self-inflating effect.