Sleeping Pads, R-Values and Backpack Hunting

By Brad Brooks

Not to overstate the obvious, but without a properly rated sleeping pad, your sleeping bag simply cannot work as advertised. No amount of down fill can make up for the lack of insulation between you and the ground. 

Your sleeping pad is as important as your sleeping bag in keeping you warm. While your bag works to keep you warm from the ambient air temperature, your pad plays a pivotal role in insulating your body from the ground. Without having a properly rated sleeping pad for the time of year you are out, as well as the temperatures you will encounter, your sleeping bag can’t keep you as warm as it should based on the temperature rating of the bag. If you are a backcountry hunter, understanding sleeping pads, R-values and how they work to keep you warm and comfortable could help you avoid a miserable nights' sleep next time you head out.

In this piece we will break down why sleeping pads are important for warmth, how they function, and recommend different R-value pads for different hunting seasons throughout the year. 

R-Values and Temperature ratings

All sleeping pads come with an "R" value, which is a measurement of insulation that measures how much something will resist heat flow. The higher the R-value, the more resistant it will be to heat flow. Hence, higher R-value sleeping pads are going to retain the heat from your body better, and are going to be warmer sleeping pads.

There is a trade-off for higher R-value pads however as pads that insulate your body better require more internal insulation, which increases the weight of the pad. So, finding the appropriate R-value without weight you down is important (more on that below).

Since 2020 most major sleeping pad brands have an independent third party ASTM certification process to decide what R-value they can list on their pads. This was a big change, and a welcomed one as you can compare apples to apples from different brands.

Sleeping Pads and How They Work

A sleeping pad has two jobs: Keep you comfortable, and keep you warm. On the second point, a sleeping pad is critical for keeping you warm, particularly when it gets cold. The way sleeping pads accomplish this goal is by keeping still, warm air close to your body and cold air away from your body (which usually comes from the ground). There are a few different ways sleeping pads do this.

1. Trapping Warm Air-Some pads use a combination of foam and air, and early generations of backpacking pads usually had a layer of foam on top of the pad with air for insulation and comfort. Foam is a great product for trapping air and making for a good night's sleep. In fact, there are still a number of pads that use the foam and air combination in sleeping pads to provide warmth. But foam is heavy relative to other materials some of the superlight sleeping pads use, and for backpack hunters a pad with foam is almost always going to be heavier than one without it.

2. Radiant Heat + Trapping Warm Air- The newest lightweight pads from most brands are attempting to trap cold and warm air in opposite directions to keep cold air close to the ground and warm air close to your body. To accomplish this inside the pad there are layers of material that run the length of the pad that trap air to create multiple layers of trapped air. That can include internal materials that reflect heat, synthetic insulation sheeting, goose down, or any combination of those materials. 

Picking the Proper R-Value Pad

There are no hard and fast rules for what R value you need based on time of year, but there are some good guidelines. How warm you will stay depends on a handful of factors like your sleeping bag temperature rating, tent and ground temperature. 

It's important to note here that R-values do not translate to temperature ratings since an r-value is a measurement of the flow of heat. This is why most big brands resist putting temperature ratings next to r-values, tempting as it may be. The closest most brands will give you is a recommended temperature range.

Luckily, we care more about dealing with real world scenarios and providing practical advice. With that in mind, we created a chart to help folks make sense of all this math. The chart below is based on R-value season guides, our experience with different sleeping pads, and our collective field experience.

 

This is a rather conservative table. You can get away with a lower R Value than the above if you sleep warm, but most people should be comfortable with the R Value pads listed above. For example, a 3.3 R Value pad can work well into October for many people, and during archery season you can get away with a 1-2 R value pad if it stays relatively warm at night.

Use this as a guide, but figure out what works best for you. 

 

Lightweight, Warm or Both

As a general rule, the lighter weight a pad is the lower the R-value it is likely to have since there is likely less material inside the pad working to trap warm air to keep you warm. For backcountry hunting, and particularly for backpack hunting, going with the lightest pad and lowest R-value you need is a good idea.

But if you ride the line between comfort and weight, be prepared to occasionally suffer. Figure out where your suffering tolerance lies, and pick the lightest pad that fits your threshold. 

In the winter months, as I've learned the hard way, be sure to take a well-insulated pad suitable for the location and temperatures you're hunting. Suffering in early September on a cold night is different than in late November when the nights are much longer.

Tips for Buying a Pad

1. Pick the Right Length-You can save some weight, particularly in the early season, by getting a pad that is slightly shorter than you are as a pad doesn't need to be as long as you are necessarily. Stack your pack at the top of your pad as your pillow so your neck is above your pad, or stuff a jacket under your feet at the end of your pad.

2. Pick the right R-Value-See above.

3. Comfort-Two or more inches of air thickness when set up is usually as good as it gets for a lightweight backpacking sleeping pad, and is usually sufficient. 

1. Buy once cry once-When you're on a backpack hunt and your pad fails, it will make your hunt miserable after a couple nights with terrible sleep. Whatever you get, get something of decent quality.

Our Favorite Pads by Season

1. Exped Ultra 3R mummy–This is my go-to archery season and summer backpacking pad. Lightweight, comfortable and I’m a big fan of the Exped valve system.

2. Exped Ultra 5R–I like the vertical baffles for keeping me on the pad, the weight is reasonable and this pad is my favorite jack of all trades pad from early archery to late October

3. Exped Ultra 7R-This is strictly for November - January hunts. Slightly heavier and has more insulation than the 5R. Great all around pad.