Updated June 2017.
In this text, I give a few basic facts about sleeping pads, which you should know before deciding to buy one for you. To choose properly, it is important to know exactly the purpose of your pad. Is it for backpacking or for camping? Is it for summer time, 3-season, 4-season?
This all will then tell you what R value the pad should have, what material is the best for you, what weight to choose.
Why is a sleeping pad important
You can understand the importance of a sleeping pad if you think about insulation and thermal conductivity. This is now my field, I am a physicist by profession. When you are in contact with cold objects, conduction takes place and you lose heat. You lose far more to the ground than to the air.
I would not annoy you with physics, but roughly speaking you lose:
- up to 40 times more heat to dry soil than to the air
- around 55 times more to a rock than to the air
- around 20-40 times more heat you lose to ice than to dry snow
- around 13-26 times more heat you lose to ice than to rock.
So you realize why it is so essential that you are well insulated from the ground, and why it is important to choose wisely the place where you sleep. What I want to say is basically the following: buying outdoor equipment is an investment, so if you have to save some money, better save on sleeping bags than on sleeping pads.
What is sleeping pad R-value
When you buy a sleeping bag, you normally have a temperature rating for it. Sometimes you will also see a warning that this indicated temperature comfort is guaranteed only if the bag is used together with an appropriate sleeping pad, sometimes from the same brand.
The properties of the sleeping pad are then described either in terms of the sleeping pad R-value, or in terms of the temperature rating for which the pad is designed.
This should not be ignored, and this holds in particular with sleeping bags which do not have insulation in the layer beneath you. Yes, there are such sleeping bags. You may see Big Agnes King Solomon bag from my another post. They rely on the insulation given by the sleeping pad. The same holds for bottomless bags like Nemo Tango Duo 30 bag.
Essentially, the R-value describes the pad’s ability to retain the warmth. The higher R the warmer sleeping pad is. These values are typically in the range from 1 to 10 but the values for some pads can be far bigger than this. This parameter depends on several factors described within this post, like the material and the construction of the pad. So for summer conditions, you will use some uninsulated pad which may have R-value of 1. Quite different is with a 4-season pad. In this case, you might not want to go below R=4.
Here is one example with R=5, Big Agnes Q Core sleeping pad:
Backpacking sleeping pads vs. camping sleeping pads
If you are a backpacker or mountaineer you will want something
In any case, you will want to find the best possible balance between comfort, warmth, weight, and price.
If this is about camping sleeping pads, then most likely you can afford more weight and size, and consequently more comfort. Depending on the season, you will probably choose some inflatable pad with features described below in the text.
Here is a video from Amazon, about sleeping pads, please have a look:
Sleeping pads for women
Yes, you are reading correctly. There are differences between pads for women and pads for men. The sleeping pads for women are sometimes shorter (to save the weight), but also have additional insulation in some important places.
You may see one good example in the picture on the right, Therm-A-Rest Women’s Trail Lite Mattress.
You should know that the same sort of differences you have with sleeping bags as well.
Construction of sleeping pads
Here you have 3 basic types:
They can be made for backpacking and camping.
Advantages of using them:
– thick and comfortable, in fact, the most comfortable of all types
– some of them can be packed to a small size, see this Sea To Summit UltraLight Mat.
– this is surely the best choice for side-sleepers
– some come with an integrated foot or hand pump.
– some are heavy, but this depends on the price
– can be punctured, and if this happens you may be in trouble.
These pads are mostly with a low R value, but there are great exceptions if you are willing to pay more. Some models have improved insulation due to some sort of fill (down, synthetic), or due to some heat-reflecting material used in their construction. The Big Agnes example given above is one of them.
• Self-inflatable sleeping pads (self-inflating foam pads, or open cell foam pads).
These are filled with some foam which expands when you open the valve and spread the pad, and it sucks the air in. You may blow some air in if you want. The outside shell is usually waterproof. The Therm-a-Rest model given in the picture above is one of them.
An open-cell foam structure is similar to a bath sponge. So you have the gas pockets which are connected with each other. They are self-inflating due to memory effect of the foam.
These pads are popular among backpackers and campers. They come in a large variety of weight (and thickness and price), but they are usually more lightweight than the air pads.
– reasonably comfortable, dependent on the thickness.
Disadvantage: not puncture-proof. Even a zipper from your clothes can puncture through it when you are sleeping. Also, if you are on a rough terrain you may be in trouble with it. There are however more expensive models with some puncture-proof bottom layer.
• Closed cell foam pads
These are most suitable for backpackers and mountaineers. Made of a thick foam, they are very good insulators but do not expect much of comfort here. But these pads are your best choice if you are concerned about punctures.
The term closed-cell implies that the gas forms discrete pockets, each completely surrounded by the solid material.
– very lightweight
– good insulators
– they usually do not absorb water
– you can trim them to fit your sleeping bag sleeve, or to reduce weight
– they do not freeze
– they are best on a terrain where there may be problems of having pads punctuated by some sharp objects.
– they are bulky, so you will see them carried by people attached to backpacks from outside
– not the most comfortable option for sure.
Size of sleeping pads
- Length: typically 72 inches (183 cm). But you will find longer versions, as well as shorter.
- Width: typically 20 inches (51 cm). Wider pads exist of course.
Winter sleeping pads
What to bear in mind?
- High R-value. Do not go below 3, preferably above 4. Both models in the pictures above are in this category.
- Choose some insulated model, or closed cell foam pad.
- The best option for an extended tour: the combination of a good and normally ultralight closed cell foam pad, and an ultra lightweight inflatable air pad like Therm-a-rest Xtherm or something similar. The combined R value of the two pads will provide exceptional insulation and you will have a great comfort at the same time.
So to conclude this text about sleeping pads, it should be understood only as a short introduction to this topic. Within this site, I give more information about various models of sleeping pads and you can find them here. I hope you will find it useful.
Thank you for reading and I hope to see some comments from you.