Back in 2015, Sea to Summit introduced a new lineup of sleeping pads (or mats as they refer to the line) made up of 6 different models utilizing their Air Sprung Cell design, an egg-crate like dot weld pattern designed to prevent the transfer of movement throughout the pad and increase a user’s sleeping comfort. The mats ranged in r-value from a low of .7 to a high of 5, and ranged in weights from less than a pound to 36 ounces.

The details of the lineup on paper caught my eye: Durable 40D fabrics, decent weight to warmth ratios, comfort, and Sea to Summit even added an anti-microbial treatment within the pad. As a backpacker that likes to stay warm and frequently encounters freezing weather even on occasion during summer months in the mountains, in particular the Ultralight Insulated sleeping pad seemed to offer the best blend of features. An r-value of 3.1, and listed weights ranging from 12.3 to 21 ounces depending on size does put the pad in a competitive position against many other lightweight sleeping pads currently on the market.

Design & Specifications

The Ultralight Insulated Mat utilizes a tapered design, and is offered in 4 sizes – X-small, small, regular, and large in orange or yellow. All mats use a 40D ripstop nylon outer fabric, and for warmth the mats use a reflective fabric layer (Exkin Platinum) combined with internal Thermolite synthetic insulation. All sizes are 2” in height. A single multi-function valve allows for inflation, deflation, and fine-tuning of air within the mat. An anti-microbial treatment has been applied within, as well. Depending on size, the mats have up to 225 individual cells. A stuff sack, repair kit, and a spare silicone valve flap are all included. Some specs can be found below by size:

X-Small: 12.3 ounces, 50x21.5"
Small: 15.1 ounces, 66x21.5”
Regular: 16.9 ounces, 72x21.5”
Large: 21 ounces, 78x25”

My size large weighed on target at 19.05 ounces without the stuff sack or accessories, with the stuff sack adding .4 ounces and the entire repair kit .2 ounces. Inflated, I measured a length of 78.5”, a maximum width of 28.5” at the top, tapering to 19.5” before the corners begin towards the feet. Overall height averaged about 2” with some cells along the edges measuring a little more or less.

Impressions & Performance

Comfort

Lately I’ve been inclined to focus both on a light pack, keeping the hiking easy as the miles go by combined with comfort once I setup camp, and the Sea to Summit is a good match for that type of approach. The bottom line is that it’s quite comfortable, with the main limitations coming from the 2” height and the tapered shape. With the limited height, I found that I had to inflate the pad to just about maximum inflation for isolation from irregularities on the ground, to keep from bottoming out on my side, and for warmth. At this inflation level and with the air sprung cell design, the mat has a different type of feel compared to other pads I’ve tried, almost what you’d expect if you took a super-thick, very high density closed cell foam mat, and combined it with an air mattress. It’s comfortable if you like a firm mattress and overall just a different feel, you can even fold the mat and interestingly it wants to stay in place on its own.

There are a few larger cells along the side, and the edges of the mat don’t collapse easily – I never found myself waking up in the middle of the night having fallen off the side. The outer fabric seems to have enough grip to help in this regard, and helps to reduce sliding, pad and you combined across a tent floor. Although the fabric is a little crinkly, if noise is a concern I found the pad is also quiet enough once it’s inflated. With the tapered design in mind I was at times limited to certain non-sprawling sleep positions, although comparing the large size to a 25” wide rectangular pad, there’s not that much difference, with most lost real estate coming in the corners and especially towards the feet. If you’re a back sleeper though, the shape might work out perfectly, and in the size large, I’m able to lay on my back with my arms also on the pad in a mummy bag. The mat does indeed seem to transfer less movement throughout, feels very stable, and feels less bouncy as you move around.

Warmth

Initially I was concerned in regards to the dot welds that go all the way through the pad, and additionally I was surprised to hold the pad up to the sun one morning and see that the insulation apparently covers most, but not all of the pad. However, whether it’s the heat reflective fabric, air trapped underneath the egg-crate design, or just the sheer number of insulated cells / all of the above combined, I was contentedly warm using the pad into the high 20’s (F) with my standard 3 season sleep system setup (20 degree bag, base layers, down jacket) and felt no coldness below unless I intentionally tried pressing the pad against the ground along the dot welds.

With a thin foam mat of the 1/8” variety like the ULA Siesta foam pad and weighing just a few ounces underneath or on top, the Sea to Summit could be taken quite a bit lower and would be appropriate even as a component of a winter sleep system combined with more insulating options.

Usability

With the one-way inflation valve, you don’t have to fight against escaping air to inflate the pad, but some type of pump sack will save some dizziness after a day of hiking. I found that the Exped Schnozzel I already had worked perfectly, and Sea to Summit now includes (not included at the time of my purchase) the Air Stream dry sack pump which is designed to double as a pack liner or very large stuff sack. This options weighs less than 2 ounces and can be had for around $40 separately.

Also available is a chair conversion kit, about $60 and half a pound. Once inflated, it’s easy to fine-tune the inflation level simply by pressing on the small button in the center of the inflation valve as you lay on the pad, then releasing it once the desired inflation level is achieved. Deflation is near instant. Packing was easy, deflate, fold a couple times and roll. The stuff sack is a good size, not so small that packing up in the morning is a challenging event, but it will save you pack space if that’s what you’re after. While I didn’t need it, the repair kit is a nice touch – self-stick patches keep the kit lightweight and easy to use – I’d rather not mess with glue in the middle of the night.

Conclusion

The Ultralight Insulated sleeping pad from Sea to Summit offers a good feature set and is a sleeping pad to consider if you’re interested in comfort and warmth for typical 3-season trips while keeping your pack weight low. Sea to Summit’s multi-function valve is a stand-out feature and one of the best designs out there, and the anti-microbial treatment is a nice touch (why doesn’t everyone do this?). A lot of it comes down to the way you sleep and personal preference – the tapered design could be limiting. 40D fabric does add peace of mind in the durability department, but lighter fabrics have proven to be durable enough for most in the ultralight sleeping pad range for years. At least in my case, if my pad isn’t packed away, it’s only used within my shelter with a tent floor and a groundsheet beneath, then packed away safely the next morning.

With a lighter fabric, it’s possible that the mat could have been made thicker for more comfort, or possibly in a rectangular shape for more sleeping real estate without that much weight penalty. Or it could have just been lighter. It’s worth exploring the full lineup to find the model that best suits your needs – Sea to Summit also offers thicker dual layer and rectangular pads. For peacefully sleeping back sleepers, the Ultralight Insulated may be close to ideal with more compromises for the side-sleeping toss and turner. Overall though, the pad is a good all-around, warm, durable, and comfortable choice across the board.

The Sea to Summit Ultralight Insulated sleeping pad retails for $170-$190 depending on size. Find it here at Backcountry as well as here at REI Co-op. For more information on how to choose the best sleeping pad, see our backpacking sleeping pad guide.

Editor's Note: This review originally appeared in Issue 22 of TrailGroove Magazine. You can read the original review here featuring additional photos, pros and cons, and our rating of the Sea to Summit Ultralight Insulated sleeping pad.