Sea to Summit Ether Light XR Pro

The Sea to Summit Ether Light XR Pro is a lightweight, insulated, inflatable sleeping pad. An R-value of 7.4 and five layers of Thermal Core insulation make it suitable for extreme cold weather. 30/40D nylon with laminated TPU makes it rugged without adding too much weight, and an efficient pump sack makes inflation fast and easy.

I don’t know about you, but finding a comfortable, lightweight, and warm winter sleeping pad was starting to seem like an impossible task to me. One brand with down insulation and a high R-value was very comfortable but far from light, and I was cold at 15°F on it. 

Another brand was very light and very warm but not very comfortable, and to make it as comfortable as possible I had to let air out so it had some give. It wasn’t very thick to begin with, though, and letting air out made it thinner and less warm. It was still the warmest one I’d used so I dealt with it for a couple winters even though it didn’t let me get the rest I needed.  

A new model was introduced and was touted as being the warmest pad ever for extreme conditions, but most of the reviewers who said it was very warm were using it in the 20s and 30s Fahrenheit. For temps around 0°F and lower its reputation was pretty evenly split. Not wanting to spend more money for what might not be a sure thing I stuck with what I’d been using. 

Then late last year I heard about the Sea to Summit Ether Light XR Pro. I’d looked at S2S winter pads before, namely the Ether Light XT, but it had a pretty poor reputation for durability. The Ether Light XR Pro, however, was getting glowing reviews everywhere. I was sold! I ordered one right around Christmas and received it just before New Year’s Day. I’ve used it three times so far and found it meets or exceeds my expectations. 

First, the specs. 

• Length: 77" advertised, 80" measured inflated
• Width: 25.2" advertised, 26" measured inflated
• Thickness: 3.9" advertised, 4" max measured inflated
• Weight: 27.9oz/790g advertised, 28.6oz/809g measured
• R-value: 7.4

The Ether Light XR Pro has an egg-crate design, with somewhat shallow dimples. The dimples aren’t welded together at the horizontal center of the pad but feel like there’s about a 2.5" gap bridged by a tube. This apparently helps limit heat from being conducted away by the dimples.

The surface of the pad is smooth but not slippery, with a thick TPU coating that appears to be puncture-resistant. Sleeping on snow it’s hard to test this, though. None of the sleeping bags I’ve used with it have slid off the pad during the night.

Unlike any other inflatable pad I’ve used, the XR Pro is very comfortable when fully inflated. This helps you stay warm by giving you every decimal of the R-value, plus I don’t feel like I’m about to roll off. But what might be the best thing about it is it doesn’t sound like you’re sleeping on an enormous bag of potato chips! Yeah, I’m talking about YOU, Therm-a-Rest NeoAir XTherm!

The Sea To Summit “XPRESS” valve is simple, with a smaller inflation valve inside a larger deflation valve. They both lie flat and lift from different sides to help prevent inadvertent deflation. There’s a one-way diaphragm in the deflation valve, and by lifting the inflation valve cover and depressing the diaphragm stem you can let air out of the pad. You can also easily roll over and add air to the pad. Pull the deflation valve plug and the air blows out rapidly. There are no moving parts to freeze in winter. 

Included with the pad are four self-adhesive Velcro strips for use with Sea to Summit’s “Pillow Lock” system. All S2S pads and pillows made since 2019 are compatible, you stick the strips on the pad and the short nap on the pillow sticks to them. Older pillows will need a nappy pillow case from S2S. No chasing your pillow around all night long any more!

The “Airstream” pump sack is integrated into the storage sack and has two different-sized nipples, a large one for pads and a small one for pillows. Just turn the sack inside out to switch. 10 sacks full will inflate it maybe 90%, but if you try to force more air in with the pump sack the sack nipple may pop out of the valve. I top it off by mouth after. 

I’ve used the Ether Light XR Pro a total of three times now, all in a tent set up in the backyard. Camping in the woods or on a mountain would have been more fun, but every time the forecasted temps were low enough to give it a good test I’ve been sick to some degree. 

The first time was on January 1st, and I was also testing out the new -10°F Western Mountaineering Bristlecone I’d recently received. I dug out the loose snow, set up the tent, and inflated the pad outside to put dry, ambient-temp air in it. Air temp dropped to -2°F that night, and I was as warm and comfy as if I’d been in my bed. Maybe warmer since there were no cats to push me to the edge of the bed where the blanket barely covered me. I was wearing Farpointe Outdoor Gear Alpha Direct pants, socks, and hoodie as sleeping gear.

The next two weeks I was sick as a dog and didn’t work so there was no camping. I also don’t think we had any weather cold enough for a valid test. 

By the week of January 18 I was feeling better and went back to work, and with temps forecasted in the negative teens Fahrenheit coming for the weekend I figured it’d be perfect for testing. I’d also received the second new winter sleeping bag I’d ordered, a -30F Western Mountaineering Cypress. So Friday afternoon I set up the tent in the cleared spot in the yard. I also set up a thermometer with the remote probe run to the outside of the tent. I again wore the Alpha Direct layer, but the socks just felt funny on my feet so this time I wore wool. 

That night I decided to use my Feathered Friends Eider -10F bag w/6oz overfill instead of the new Cypress bag. I’d used it a few times in similar temps on my XTherm and had been absolutely toasty warm so I figured I’d use it as a control so the only variable would be the pad. 

The outside temp was -4°F when I went out to the tent, and I was so warm in the bag that I first had to stick my head outside the bag hood and then unzip the bag to about my elbow for venting. Snapping the snaps at the top of the zipper kept too much cold air from coming in. 

What I did notice almost right away is that I didn’t feel warmth being reflected back at me like with the XTherm. I didn’t feel any cold at all, I was toasty warm but just didn’t feel like I had a heat source under me. Comfort-wise the XR Pro is head and shoulders above the XTherm. I mean, there’s just no comparison. 

So I slept, waking up too often to roll to a different position and put pressure on my bad shoulder from a different direction. In bed I can put my arm above my head but not in the tent. I checked the thermometer about 2 hours after going to bed and it was -9F. At the time I zipped the bag up, pulled my head into the hood, and snapped the neck collar but didn’t tighten the drawstring. I was still toasty warm with no cold coming through the pad except for a tiny, tiny, barely noticeable bit in my hip when I slept on my side. I’m not 100% sure it was coming through the pad because the Eider has continuous baffles and in the morning I found a spot near the zipper on the bottom half with very little down. So the cold may have been coming in there. But like I said it was so minor that it didn’t affect my sleep. 

I woke up a little before 7am, a check of the thermometer showed an overnight low of -14F and a current outside temp of -13F. During the night I’d adjusted the Sea to Summit pillow and the Pillow Lock Velcro strips all detached from the pad. I had the XTherm inflated and ready to roll onto if the XR Pro was cold, so I’d just grabbed the pillow from that, put the elastic strap around the XR Pro, and went back to sleep.

During the day I brought the XR Pro and S2S pillow inside, let them warm up to room temperature, and reattached the Pillow Lock strips after cleaning their spots on the pad with rubbing alcohol. I also vigorously rubbed them into place in case a bit of heat helped the adhesive set. After attaching the pillow I brought the pad back out and inflated it until my lungs couldn’t get any more air in it. I also brought the WM Cypress out to let it fully loft. 

Saturday night wasn’t much different than Friday night. The overnight low outside was 1 degree colder at -15F, 4 degrees warmer than the forecast. I wore the same sleeping layer. I adjusted the pillow a couple times during the night and 3 of the 4 Velcro strips stayed attached to the pad. Again I didn’t feel any cold coming through the pad but I wasn’t quite as warm in the new WM bag. I never needed to unzip it to vent, I have a theory but I’ll save it for if I review the bag in the future. 

My thoughts on the Sea to Summit Ether Light XR Pro? It’s now my go-to winter sleeping pad. Comfortable, quiet, and warm, easy and quick to inflate with the included pump sack, and the Pillow Lock system that I was sure was a gimmick worked well once I took a little more care attaching the Velcro. Sorry, XTherm, you’ve just been relegated to loaner or spare! Warmth and comfort are very subjective, but if you’re looking for a warm, comfortable sleeping pad for subzero temps you owe it to yourself to check this one out. 

Background

3 nights in subzero temps on this particular pad, countless nights on other inflatable and closed-cell foam pads.