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When out camping, it is especially in cold weather where keeping warm is of the essence. Speaking of keeping warm, your sleeping pad R-value comes in handy. In this respect, a high air mattress R-value indicates that your pad has more insulation and gives warmth while a low R-value indicates less or no insulation hence proves how either case can result in a chilly night.
What is R-Value?
Simply, the R-value is a factor of expressing the given material's resistance ability to heat flow. To sleeping pads, it tell you how well your sleeping mat resists heat loss. The higher R-value the better the sleeping pad is in terms of keeping you warm by blocking your body heat from being disseminated into the ground.
How is R-Value Tested?
The ASTM standard guarantees us that every pad we purchase has undergone consistent and stringent testing protocols.
These protocols involve subjecting the pads to compression between a hot plate at 35 degrees Celsius, emulating body heat, and a cold plate at 5 degrees Celsius, simulating ground conditions.
Testers then monitor the amount of energy the hot plate consumes to maintain a steady 35-degree temperature over a duration of four hours.
Reduced energy consumption signifies higher insulation capacity, while increased energy consumption indicates lower insulation capability.
Choosing the Right R-Value Sleeping Pad
Choosing the right R-value for sleeping pads narrows down to the conditions you're planning to camp in.
For summer, any pad with a rating of 1-2 should be able to serve you just fine. So, buying a pad for 3-season camping with an R-value of between 3-4 would fulfill your camping needs.
If you intend to camp in cold weather, get a winter sleeping pad for an R-value over 5, that ensures your warmth and comfort in cold weather.
Here's a table that shows how R-values correspond to Temperature Ratings. published by SectionHiker, where you can see the specific R-value versus temperature correspondence.
Chart from SectionHiker by Philip Werner
IS R-value really useful for sleeping pad?
It should be noted that due to actual camping environment humidity, wind speed, and other factors, the insulation effect of the sleeping pad is fluctuating above and below the R-value corresponding to the effect.
In fact usually the insulation effect will be a little lower than the test value. This is also clearly mentioned in Rex Sanders' article: Improving R-values For Consumers.
For shopping for a sleeping bag, it would be more appropriate to pick one with a slightly higher R-value, or more simply put, you can just pick a high R-value product unless you can't accept its weight.
Will sleeping pad R-value over 4 over heat?
The level of R-value impact the way in which the sleeping pad insulates your body as well as the ground or earth from the heat. It does not fully represent all the insulation you will get when using a sleeping pad.
According to many practical experiences- high R-value (5 or more) has slight effect on overheating in warm weather and big - on warmth in cold weather, so if the budget and the weight of the sleeping pad are acceptable - purchasing sleeping pad with high R-value is the best choice.
Conclusion
The R-value of the sleeping pad determines how well it insulates the body from the ground, and it is a standardized figure tested as per the ASTM standards.
The safest guess about the proper R-value to take for a sleeping pad is typically going to be dependent on the ambient temperature of your camping environment, and, if you want to use one air mattress only for all the scenarios in all 4 seasons, it is well worth considering buying a high R-Valued sleeping pad!
