Cold-Weather Sleeping Pads: What does R-Value mean?

I recently went on an ice fishing trip at a mountain lake here in Montana. We fished hard for burbot and the plan was to overnight in a tipi tent with a stove. The low for the night was going to be 13° Fahrenheit. But since we planned on having a stove, I wasn’t too concerned with having a sleep system for extreme cold. So I packed accordingly, bringing a lightweight sleeping pad and sleeping bag that were rated for warm to cool temperatures.

Well as the night progressed and the burbot started biting, we got too confident and decided to sleep in our shanty on the snow-covered ice, without a stove instead.

That was a mistake. At around 2 am we decided to put the rods down and get some rest. However, at this point, it had really gotten cold. Unlike my friend’s gear, my sleep system wasn’t up for the cold-weather challenge. I tried to suck it up, but after a while, I couldn’t handle it anymore. For my own safety, I decided to make the trip across the lake to heat up and sleep in the car. All while my friend, who had the right cold-weather sleep gear, was out there fishing for burbot all night long.

So what’s the moral of this story? Make sure you have the right sleep system for the situation. If I had the right sleeping pad and a sleeping bag for extreme cold, I might also have been able to fish for burbot until the morning.

Chances are you already have a sleeping bag rated for extreme cold. Yet, a sleeping bag by itself won’t do you much good. If you were to roll out your sleeping bag and lay directly on the ground, you would quickly get cold. The ground is usually colder than your body, especially in the winter. Therefore, it will act as a heat sink and continue stripping your warmth away until you both reach equilibrium. This is due to conductive heat loss between your warm body and the cold ground.

To overcome this, you want to pair that sleeping bag with the right sleeping pad. An important metric to consider when buying a cold-weather sleeping pad is the R-value. Many outdoor companies will test their sleeping pads and provide the R-value rating.

What is R-value?

The R-value of the sleeping pad will help you achieve proper insulation. The pad’s job is to create thermal resistance between your body and the ground.

The R-value measures the amount of thermal resistance of the sleeping pad. Typically you will find sleeping pads with R-values ranging from 1 to 6 or above. The higher the R-value the greater the ability to resist heat loss to the ground. Simply said, the more R-value the warmer you are going to be, setting you up for a good night’s sleep, allowing you to be prepared for whatever adventure lays ahead in the next day.

A sleeping pad with an R-value of above 4 is usually considered to be suitable for 4 seasons. However, 5.5 or above should be good enough when the expected nighttime low gets close to 0° Fahrenheit. Although, if you are a cold sleeper, adding an extra R-value of 1 is recommended. More R-value can also be achieved by stacking two sleeping pads on top of each other.

Next time you go looking for a cold-weather sleeping pad, make sure to consider its R-value.

A word of caution: Being comfortable and warm depends on other variables as well. R-value alone is not enough. You should consider the R-value of your sleeping pad in the context of your entire sleep system (including sleeping bag, shelter, clothes, weather, terrain, etc) to insulate yourself properly and protect you from the elements.

Author: Poldi Wieland