Inflatable sleeping pads: finding comfort when sleeping on the ground

Introduction

The most iconic sleeping pad among long-distance hikers is the Therm-a-Rest Z-Lite. It’s puncture-proof – the Achilles’ heel of modern-day ultralight inflatable sleeping pads for backpacking. It’s a bit light on comfort and warmth, and it’s heavy and bulky for the little bit of warmth and comfort it does provide. However, if you’re a long-distance hiker on a budget, tough enough to sleep on a hard bed, and just want to throw your pad down on the ground without worrying about cactus spines and spruce needles, then the Therm-a-Rest Z-Lite may be your match made in heaven.

I slept on a foam pad well into my late 20s, and started experimenting with inflatable sleeping pads around 1998. At that time, the best inflatable sleeping pads were also made by Therm-a-Rest, the self-inflating open-cell foam-filled pads with durable fabric outers. They were about an inch to inch-and-a-half thick, weighed a pound and a half, and failed more commonly as a result of seam failures than fabric punctures. Seams have been more durably welded and fabric puncture resistance-to-weight ratio has improved, but the overall design hasn’t changed in the past three decades. The Therm-a-Rest Prolite Plus defines the current state-of-the-art in this pad category and the Therm-a-Rest Prolite Apex incorporates lighter fabrics and more thickness to boost comfort and warmth a little.

And then, in the early 2000s, we saved weight in the most obvious way: we just made smaller pads.

Evolution of the inflatable sleeping pad

As you can see from the table above, each of these styles of pads suffers from the following limitations:

• low comfort (thickness)-to-weight ratio
• low warmth (R-value)-to-weight ratio

However, in 2009, Therm-a-Rest introduced the first ultralight, uninsulated, non-self-inflating mattress to the backpacking market, the NeoAir. It was 3 inches (7.6 cm) thick, had an R-value of 2.5, and weighed only 14 ounces (397 g) in a 20 x 72 inch (51 x 183) cm mummy-shaped form factor. Although its weight was unremarkable (it weighed the same as the Z-Lite), its comfort-to-weight ratio certainly exceeded anything else on the market by a long shot.

The design characteristics of the NeoAir mattress that distinguished it from the Prolite mattress were the insulation, mode of inflation, and thickness. NeoAir mattresses were not insulated; they required manual inflation with your mouth or a bellows-style pump sack, and they were thick. That thickness translates to comfort, and it’s this feature alone that has resulted in their growing popularity over the past 15 years.

Since then, non-self-inflating mattresses have become the dominant product category within the overall backpacking sleeping pad market. NEMO, REI, Sea-to-Summit, Big Agnes, Zenbivy, Exped, and Klymit each offer several products within this category.

Some are insulated, some are not. Some are rectangular, others are mummy-shaped. Some are narrow (20 inches / 51 cm wide), some are wide (25 inches / 64 cm or wider). Some are short (down to about 47 inches / 119 cm), some are long (up to about 77 inches / 196 cm). Some are light (as light as 8 ounces / 227 g), some are heavy (as heavy as 40 ounces / 1,130 g). Some are quiet, others are noisy. Some are durable, others are fragile. Some are more stable, others are more wobbly.

This product category, now comprised of dozens of different pads, has become commodified in the past five years or so, and the differences between many of the brands are a bit subtle.

However, two manufacturers – NEMO and Therm-a-Rest – have become market share leaders. The reason for this is two-fold:

1. They have invested research and development resources into making these pads warmer using reflective surfaces and baffles (i.e., no foam or other high-loft fill materials).
2. The quality of their construction and fabrics is relatively high. They tend to be fairly reliable in terms of seam integrity and fabric puncture resistance.
3. They were the first companies to introduce regular length (72 inches / 183 cm), wide (25 inches / 64 cm) pads.

It is this latter feature – the “regular-wide” pad – that has probably changed my sleep comfort more than anything else in recent years. A wide pad is both more stable while sleeping or changing positions, and more comfortable because it provides a platform for resting your arms at your side (back sleeping), or for splaying your arms and legs into more comfortable, natural sleeping positions (side sleeping).

Having slept on more than 25 pads over the past three years, five pads stand out. Two are made by NEMO, two by Therm-a-Rest, and one is from a relatively small brand – Zenbivy. All of them represent each brand’s state-of-the-art models introduced in the past year.

The following table identifies the pads and compares their specifications for regular-wide size options:

Table: High R-Value Sleeping Pads

The following table outlines five sleeping pads worth considering if you're in the market for a high-value pad. Therm-a-Rest and NEMO are the market leaders. The Tensor and NXT series represent the market's current state-of-the-art in ultralight sleeping pad insulation combined with durable, lightweight fabrics. The Zenbivy Flex Air is unique for its soft, stretchy fabric surface, and is probably the most comfortable high-R-value pad to lay on with bare skin.

	Shape	Dimensions	Thickness	Weight	R-Value	R/Weight (oz)
NEMO Tensor All-Season Ultralight Insulated Sleeping Pad	rectangular	72 x 25 inches (183 x 64 cm)	3.5 inches (8.9 cm)	19 oz (539 g)	5.4	0.28
NEMO Tensor Extreme Conditions Ultralight Insulated Sleeping Pad	rectangular	72 x 25 inches (183 x 64 cm)	3.5 inches (8.9 cm)	22 oz (624 g)	8.5	0.39
Therm-a-Rest NeoAir XLite NXT Sleeping Pad	mummy	72 x 25 inches (183 x 64 cm)	3.0 inches (7.6 cm)	16 oz (454 g)	4.5	0.28
Therm-a-Rest NeoAir XTherm NXT Sleeping Pad	mummy	72 x 25 inches (183 x 64 cm)	3.0 inches (7.6 cm)	20 oz (567 g)	7.3	0.37
Zenbivy Flex Air Mattress	mummy	72 x 25 inches (183 x 64 cm)	3.0 inches (7.6 cm)	24 oz (680 g)	4.8	0.20

Comfort: stability, warmth, and noise

In field use, my personal preference leans towards the two pads from NEMO – the Tensor All-Season Ultralight Insulated and the Tensor Extreme Conditions Ultralight Insulated. They are quieter and more stable than Therma-a-Rest NXT pads. And while I do think the Therm-a-Rest XTherm NXT is warmer than the NEMO Tensor Extreme Conditions (see below), I find the Tensor Extreme to be sufficiently warm for sleeping on snow in any 3-season condition, and more than warm enough when paired with a Gossamer Gear Thinlight underneath it for winter camping in the Colorado and Wyoming Rockies.

Maximum warmth-to-weight ratio

If you value pure warmth (as the primary measure of performance) for the weight, the Therm-a-Rest NeoAir XTherm NXT is the new gold standard for warmth-to-weight ratio in inflatable sleeping pads (because of differences in baffle and insulation design, and based on our not-yet-published thermal kettle tests). Considering that it’s a true four-season pad that weighs only 20 ounces (567 g) in a regular-wide size (with a mummy shape), that’s quite a feat. Those who find the horizontal baffling of Therm-a-Rest NeoAir-style pads comfortable can enjoy a few less ounces over the NEMO Tensor Extreme. The only caveat: NXT pads are little noisy (crinkling sound) when moving around on the pad. Tent mates beware!

Stretch fabrics: soft, quiet, and stable

Finally, there’s one more pad that’s somewhat unique and worth keeping an eye on – the Zenbivy Flex Air Mattress. It’s fairly warm (R-4.8) and fairly light in a regular-wide size (24 ounces / 680 g). Its unique feature, however, is its stretchy top fabric. While it sounds a little strange to put stretch-fabric on a sleeping pad, you may change your mind after lying on top of it. It’s quiet, soft, and the stretch keeps it from wobbling around a bit less when you move around on the pad. The effects are subtle and not earth-shattering, but they are noticeable and may contribute to additional comfort for you.

Pumps and Pump Sacks

Inflatable sleeping pads have spawned a market for inflation pumps and pump sacks. Most inflatable mattresses include an inflation bag (“pump sack”) that works as follows:

1. Attach the bag to the pad’s inflation valve (using the bag’s built-in adapter).
2. Fill the bag with air.
3. Roll the bag opening over to seal it, and expel the air into the pad like a bellows.
4. Repeat steps 2 and 3 until the pad is filled.
5. Remove the bag from the pad and top off with a few breaths.

An inflation bag can be filled with air in one of two ways:

1. A Bernoulli effect – where you lightly blow air into a narrow opening of the sack, and Bernoulli forces draw additional air inside.
2. A scoop effect – where you scoop the inflation bag’s large opening through the air or point it into the wind to fill it up.

Some of us try to take advantage of multiple-use inflation bags, by using them as pack liners or stow bags for other gear. Narrow-mouth bags don’t work well for this, but wide-opening (“dry-bag style”) inflation bags do. One of the most popular options in our community is the Exped Schnozzel.

Usually, an inflation bag can fill a sleeping pad with air with about 4 to 6 bag fills (less for a larger bag like the Schnozzel, more for a smaller bag like those shipped with Zenbivy pads).

However, if you still think that’s too much effort, or you otherwise don’t want to fuss with an inflation bag or use it as a multi-use item, then there are tiny battery-operated and USB-rechargeable pumps available. Most of them weigh less than 5 ounces (142 g), and most of them (especially those available from mega-online-retailers) are junk. I’ve purchased several to test, and they often lack quality construction, water resistance, battery life, and pumping power. Several have failed in the field after only a few days of use.

If you are looking for a lightweight, quality pump that has good power, long battery life, a fast recharge time, and is durable enough for sustained outdoor use, consider the Flextail Zero Pump.

Related

• Commentary: Sleeping Pad R-Values: Not That Useful
• Gear Review: NEMO Switchback, a Z-Lite alternative