The best air mattress on the market right now is the NeoAir made by Cascade Designs Therm-a-Rest.
I was lying on mine one night in the tent during an 8-day hike of the Haute Route in the Alps. A strange sizzling sound began.
At first I thought I was being attacked by insects under the tent.
Then my NeoAir began to swell in one small spot.
Bizarre.
Each night after being inflated the swelling increased in size. It seemed to stop when internal pressure reached a specific point. (under-inflated)
I slept on the thing anyway though, being a savvy hiker, I was actually carrying a second small air mattress, using it as a pack frame and pillow.
I’m BRILLIANT to have a back-up. Right?
Sadly, my “pillow” had developed a slow leak. It was worse than the NeoAir.
The NeoAir is not widely available in Europe as yet. By luck I happened to find a demo model in Chamonix, France reduced to 109 Euro (US$156).
I’ll be returning the damaged NeoAir on warranty when I get home.
But I’m wondering if this was a fluke. Or a design flaw in a new product. Leave a comment if you’ve heard of this happening to any other NeoAir mattresses.
I’ll post it to Twitter tagged #NeoAirFail, as well.
Cascade Designs Therm-a-Rest – official NeoAir webpage
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UPDATE: I’ve only heard of one other incidence of this happening. My NeoAir was replaced under warranty.
besthike.com 
Thermarest – I have 2 of them and they both had buldges, I am going to send back to the manufacturer to see what they say.
We have 2 mattresses bought last year. Both had the say use – probably about 30 nights and bizarrely both have started to fail at the same time (although bought from different places). We found the did not fail massively and by underinflating could keep using for a while.
We have had an old thermarest delaminate but that was our fault for leaving inflated in the sun – don’t do this!!!
We are sending ours back in the UK so will wait to see
Actually, my current NeoAir has worked perfectly for many nights, perhaps 80.
I see no signs of failure yet.
Need to pop the valve during the day if you leave it in your tent, then re-inflate at night
I’ve just hit this issue as well, on one of the edges. probably have 50 nights on it. My friend’s mattress also just started to buldge as well – near the center, even though he bought his a year after I have. Will be shipping this to Thermarest next week – I just hope this is not something the newer models have fixed by now.
I had the same problem with my neoair xlite after maybe 20-30 nights…
http://www.avventurosamente.it/vb/120-sacchiletto-e-stuoini/22992-m%C3%A8-schioppato-il-neoair-xlite.html
Hi,
im french and i had the same problem.
exactly the same…
my 5 years old matress was replaced under garanty by a new neoair xlite.
thermarest is a serious company, you can rely on their products.
thanks for your post.
Being a lifetime warranty, they don’t ask the receipt fot the warranty to be valid, do they? Cause I think i’ve lost mine
I’ve replaced mine with no issue. They did not ask for a receipt (which I actually do have). Great customer service and warranty.
wow that is weird, we use a thermarest as well but had no problems what so ever. Mine has been going strong since 2012! We do use a different model… maybe it is an issue with this specific model?