Foam Mattress Pads for Camping

Getting a good night’s sleep when camping requires a good sleeping bag designed to keep you warm and comfortable at the lowest temperatures expected. And while there are many great bags out there, no sleeping bag will keep your bottom side warm. Why? Because once in the bag, your weight decreases the loft of the bottom fill, making it a poor insulator. All fill materials, whether cotton, natural down, or synthetic work by trapping a layer of dead air. This thin layer of air is easily heated by your body. But this can only happen if the fill material remains aloft. Much of your body heat loss occurs through the ground, a process known as “conductive” heat loss. So, it’s important to keep a layer between yourself and it. Using foam mattress pads for camping is a great way to keep that bottom side warm.

Additionally, sleeping pads, whether foam or air filled, should provide a cushion against the hard ground. But, not all foam mattress pads are good at both. Here is what you need to know about this important piece of camping gear.

Types of Foam Mattress Pads

There are really only two types of foam mattress pads for camping: those made with Closed cell foam and those made with Open cell foam. Both have inherent advantages and disadvantages. We’ll explore that next. But first, what is Closed cell and Open cell foam?

Closed Cell foam – This inexpensive pad material is both lightweight and dense. Modern sleeping pads are made of EVA (Ethylene vinyl acetate) closed cell foam. Think yoga mat and you’re close. They are a popular choice among backpackers and suitable for short term car camping as well. Before graduating to inflatable air mattresses, my early days of car camping found me sleeping on top of a thin, spongy closed cell foam called Ensolite. While extremely lightweight, those older foam sleeping pads tended to compact down throughout the night, leaving you feeling like you were sleeping on very little cushion by morning. Fast forward a few decades and now you’ll find leading outdoor gear companies such as Therm-a-Rest®, and Exped offering higher quality, better insulated, closed cell foam products.

Open Cell foam – Open cell foams are composed of pores that form an interconnected network that is relatively soft. Open cell foams will fill with whatever they are surrounded with. If filled with air, a relatively good insulator can be made. Open cell foam is used mostly in self-inflating mattress pads. As remarkable as the name implies, these pads really do self-inflate when unrolled and left for a few minutes with the valve open. Additionally they can be firmed up, if desired, by simply adding a few puffs of air before closing the valve. Started by two former Boeing Aerospace Company engineers, Cascade Designs developed the worlds first self-inflating mattress pads using open cell foam technology in the early 1970’s. Now a leading manufacturer of outdoor products, they offer both closed cell and open cell mattress pads using the brand name Therm-a-Rest®.

Advantages and Disadvantages of Closed cell and Open cell foam Pads

Both types of foam have good and not so good qualities. Because of this, manufacturers and outdoor retailers sometimes recommend using two pads – a closed cell foam pad on the bottom with an open cell foam pad on top. And at least one manufacturer, Big Agnes, offers a detachable top layer of soft memory foam that can be added to nearly any base pad. Below details the advantages and disadvantages of both types of foam technology.

Closed Cell Foam

Advantages – Lightweight. Waterproof. Inexpensive. Durable. Can be used instantly with no setup

Disadvantages –Bulky, especially larger sized pads. Can catch on thick brush if carried on outside of pack. Provides only moderate insulation. Firmer foam is just not as comfortable as open cell foam.

Open Cell foam

Advantages – Self inflating. Comfortable padding with adjustable firmness. Excellent insulator. Very compact when packed.

Disadvantages – Requires setup time. Can be punctured leaving it useless, though easily field repaired. Must be careful to NOT get dirt in the valve. More expensive than closed cell pads. Must remain inflated for long term storage.

Sizes and Shapes

Camping mattress pads come in various lengths to accommodate all body sizes. Short (3/4 length), regular, and long length sizes are the most common. They are available in a standard 20 inch width. Longer sizes are typically 25 – 30 inches wide.

Closed cell foam mattress pads are generally rectangular shaped. Open cell foam pads are available in mummy, rectangular and semi-rectangular shapes where the head end is gently curved outward.

Smaller sized foam sleeping pads are available for women and feature added warmth in the hips, torso and feet. Most manufacturers now offer kids sized sleeping pads as well.

It’s important to choose a sleeping pad that provides ample space for your entire body. Heat loss can and will occur if any portion of your body comes in contact with the ground, even through your sleeping bag.

Insulation and Comfort

The warmth of a mattress pad is indicated by its R-value and is provided by most manufacturers. R-value measures a material’s resistance to heat loss by calculating the difference in temperature from one side of the material to the other. The higher a pad’s R-value, the better you can expect it to insulate you from cold surfaces. Foam mattress pads have R-values in the range of 1.0 – 9.0 with higher numbers found in open cell foam pads.

In general, the thicker the foam mattress pad, the warmer it will keep you and the greater cushion it will provide. This is true for both closed cell and open cell foam pads. This is not true for air mattresses that, although provide plenty of sleeping cushion, require your body to heat a large volume of air. Remember, it’s your own body that provides the heat by warming a thin layer of trapped air.

Closed cell foam is naturally more dense than open cell foam and therefore your body can easily heat the top layer. However, the dense, more rigid nature of closed cell foam makes it less practical to transport – it just doesn’t roll up or fold to a very small size. So, you will find closed cell foam pads typically 1/2 to 3/4 inches thick. In contrast, open cell mattresses are typically 1 1/2 to 3 1/2 inches thick. This thicker pad provides both increased warmth and cushion when sleeping and once deflated, are very small and compact.

Buy a sleeping pad based on use

When shopping for foam mattress pads for camping, consider how the pad will be used. And think about how you sleep at home. Ask yourself these questions:

• What type of camping do you usually do – car camping or backpacking? If you only do car camping, then weight is not a consideration. Realistically, you can buy any sleeping pad that will keep you warm enough and provide ample cushion. If you’re a backpacker, weight and pack size are two very important considerations.
• What season do you typically camp? It’s really the sleeping pad that insulates you from the ground, so it’s important to buy one with a high enough R-value to keep you warm in the coldest weather encountered. But how do you translate R-value to warmth? I have found no way to directly convert R-value to temperature rating. I believe there are too many variables to accurately do so. However, some manufacturers provide a temperature rating as well as an R-value. Use the pad temperature rating to compare it to your sleeping bag rating. The pad should be rated for a lower temperature than the sleeping bag.
• What type of a sleeper are you – cold sleeper or warm sleeper? This is something to keep in mind as a way to influence your choice of the sleeping pad’s warmth rating. Some people sleep completely covered up, while others prefer little or no covers at all.
• How firm is your bed’s mattress at home? If you prefer a firm mattress, consider using a closed cell sleeping pad. If you prefer a softer bed, consider an open cell mattress pad and perhaps add a top layer of memory foam for additional cushion.
• Are you a still sleeper or do you toss and turn at night? Most foam pads come in standard 20 inch widths. Consider getting a wider pad it you tend to move around a lot when sleeping. Additionally, many sleeping bags can be connected to the pad using built-in straps. And, some sleeping bags forgo the bottom insulation all together and instead provide a pocket to slide a sleeping pad into – giving it no chance of sliding off.

Brands and Models

There a several brands and models of foam mattress pads on the market. However, the market is dominated by Therm-a-Rest, a division of Cascade Designs. Other big players include Big Agnes, Kelty and Exped. Each of these companies offer a variety of quality foam pad products. The chart below details each of their popular models and makes it easy to compare features.

From the chart above, it’s easy to see that one company, Therm-a-Rest, leads the pack when it comes to sheer quantity and variety of foam mattress products. This is no surprise considering the company got their start after pioneering the use of open cell foam pads nearly 40 years ago. But others have since entered the market and continue to offer excellent products as well, including both foam based pads and air mattresses. The increased competition is only good for us campers looking for quality sleeping pads at bargain prices. And, when combined with a good tent and sleeping bag, a great night’s sleep is sure to happen.