Innovation in simplicity. That’s the main concept behind the Proton Blanket from Thermarest. It’s a lightweight, waterproof, breathable, synthetic blanket that can be used around the campfire, outside of the tent, or cinched up into a quilt for sleeping in warmer weather.
The blanket is built from high end EraLoft synthetic insulation. It’s a waterproof, breathable insulation that retains it’s warming properties even when wet. The fabric of the blanket is 20D polyester and utilizes ThermaCapture technology, which is a practically weightless coating that’s applied to the inside of the fabric. This reflects heat back onto the sleeper, increasing warmth and allowing the blanket to heat up the user faster. The blanket comes in two colors, includes a sewn in stuff pocket for storage, retails for $119.95 and weighs 1 lb 2 oz. Dimensions are 75″ x 57″ with a foot tapering to 40″ wide.
What I liked
Warm summer nights call for something a little more subtle than a slower cooker mummy bag. That’s where the Proton Blanket really comes in handy. Warm without being too hot, it manages to provide a very cozy night’s sleep into the low 60’s or perhaps even into the 50’s if you’re a warm sleeper without all the weight and bulk of a more traditional sleeping bag. At just over a pound, this saves a lot of weight and an exceptional amount of pack space (about half the size of most ultra light sleeping bags). When even the blanket becomes too hot, it’s nice to just kick it off, perhaps leaving it covering just the feet for a little creature comfort while drifting off to sleep. 
The Proton Blanket is the shape of a generously sized blanket or throw with a gentle tapering to the feet. Wide enough to cover my entire body and long enough to be turned down like a comforter, I can wrap it around me or simple shuffle it to the side if needed. It can also be cinched down at the foot, allowing it to trap more heat for extra chilly nights or surprise temperature drops. Additionally, there are also small snap clips that allow the pad to be clipped to some Thermarest sleeping pads to seal it against a pad, reducing heat loss; Very helpful if the temperature drops below expectations. I’ve also found that you can use string combined with these clips to lace the blanket to a sleeping pad shoe lace style for the same effect. If I get too hot, it’s mighty nice to be able to slide out a let or even turn down the blanket to my hips for maximum venting. Check out the Apogee Quilt if you need something similar to this but a little warmer (40 F for men).
All around it’s a very comfortable piece of gear. The filling is light and fluffy, the fabrics are silky smooth, and and having the ability to simply turn down the blanket like you would at home adds certain creature comforts to the design that can only be appreciated first hand. Having no zippers to deal with is always nice too, as there is no struggle getting in and out of bed.
Part of the design that’s easily overlooked is the fact that the blanket is waterproof. This means you can drag the blanket out of the tent if there is a light drizzle or clouds blowing through, without worrying about it wetting out. The droplets simply run off or bead up, and the blanket continues to provide precious heat for the user. This also means that bag isn’t susceptible to getting wet from dew, condensation, sweat, or mist rolling off of a river. This enhances the usability, and adds a lot of flexibility to when the bag can actually be used. It’s also nice that the bag is built from polyester, which is tougher and resists abrasions better than nylons. Hanging out in the clouds or behind a waterfall, it’s going to do it’s just just fine.
What I didn’t like
The waterproof materials and the Thermacapture technology do result in a somewhat plasticy feel at first. They don’t quite reach rain jacket levels, but it certainly doesn’t feel like traditional polyester at this point. Luckily, with a little use the materials do soften up and become more fabric feeling. I’ve only noticed the effect once I first entered the blanket, however. I quickly learn to appreciate the feel once the warmth settles in.
Overall
I’m a big fan of the lightweight, no fuss functionality of a technical blanket. They provide an excellent alternative to sleeping bags that are simply too hot and bulky for the balmy summer months, and can be paired with other sleeping systems for extra warmth or camp side comforts around the fire or even just in the grass. The waterproof fabrics and cinching foot box only adds usability to a wonderfully diverse range of options. I adore the ability to pull the blanket out of my tent while catching a nice view of the stars late at night, and it’s quite usable around the house and while traveling too. Being so useful, weighing just 1 lb 2 oz and costing only $119, it’s hard to not recommend one of these to any camper.
Highly Recommended
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For more information on Therm-a-Rest and their excellent line of gear, check out www.thermarest.com
I wanted to send a special thanks out to Therm-a-Rest for their support and for providing this excellent piece of equipment to review. We couldn’t do this without their help. Thank you so much! Our full disclosure can be found on the about me/contact page.
TreeLineBackpacker 
We bought 2 of these and really like them. We wouldn’t use them much below 10 degrees, but we sleep warm and if you don’t, I’d suggest 12 as a guide for a minimum night time temperature.
These feel astonishingly insubstantial, but they work – you can feel the warmth trapped by them almost instantly. They take up much less than half the space of our bags and weigh only 513g each. They have allowed us to shed around 1.6 kg in pack weight. And we can use smaller packs.
Downsides? That clip system to wrap around the mat is too tight a fit for me, and I am a bulky medium size, at best. If you are large you won’t fit and I don’t advise you to try – the clips will plainly not take any level of strain.
If you are a restless sleeper you may shrug this off in the night and wake up cold. The blanket is a good size given it’s purpose – ultra light weight alternative to a sleeping bag in warm weather – but it isn’t a generous size; Enough, and no more. Strapping six footers may feel short-changed!
Even so, strongly recommended, if you know what you are doing.
Hi Tar,
Thanks for pointing this out. I’m a smaller guy myself, so I don’t really run into these issues. It’s always nice to hear from others on their experiences. These help when people are researching them for themselves.
I suppose you could always route in your own string on the clips to allow for some extra space inside. have you made any modifications to yours?
None yet. Quite content to use them as blankets. They are the answer in high summer; Could never quite justify the expense of 3 ultra light sleeping bags, which would in any case bulk larger and weigh more.
Astonished to be able to dispense with 40L packs and travel instead with 25L daypacks.
Saw a Kiwi PCT hiker who was travelling exceptionally light. 30litre bag
She had something similar to this.
Saying underside of sleeping bag is a waste because body squeezes the air out.
Are there various grades like this?
Hi Tom,
Yep. She was right about the underside being mostly useless. Flattened insulation has no space to trap air, thus no insulation.
Various grades? Not entirely clear what you mean. But, giving it a shot, both down and synthetic insulation have the same issue. Foam, not so much. This is why foam pads make such good insulation!