Sleeping pads: R Value

From the Therm-a-Rest folks themselves (courtesy of Zeke):

For that length of time I would be concerned whether the internal insulation is still in place or if it has moved around to the point of being ineffective.

We have had several days with a max daytime temperature of 7 c (44f)
The other day it was sunny and at that temp I was working outside with just a 200 Merino T (and a beanie).
Yesterday I was walking around in the same temp with that T plus a thick fleece and a down vest as well as the benie .
The temp was the same but just grey and damp.
The point here is that there are many variables when it comes to keeping/feeling warm.

From what I understand, R values are linear so an R 3.9 mat would give about 20% more insulation than a 3.2 mat or ,say, would compare with n 3.9" loft sleeping bag against one with a 3.2 " loft.

BTW :
"Interestingly enough, with their method, the Thermarest pads test higher than their spec'ed values, while the Big Agnes pads generally come out lower."
From memory Thermarest gives their R ratings at 80% inflation.

BTW 2 :
Those bloated mat photos reminds me that it is a very good idea to never  leave your mat somewhat inflated in the sun.
Not that it is the only way the blow up happens but it can happen if you do.

So you've continued to buy what you consider a poorly engineered product since 1982.

Fascinating.

You weren't reading previous posts. Eight out of 35 isn't bad, plus these pads were lived on and used daily for years. Remember the 21 years at the tipi? My only sleeping pads during that time (and consequent backpacking trips) have been Thermys. Long term use = more failures. Thermarest just hasn't yet figured out which glues to use.

But then the same could be said for Exped baffle welding technology. Still trying to figure it out. People in the field get to use these items until they fail and then we offer feedback. It's called gear reviews.

Ever heard of sarcasm? My example isn't the only cached Thermarest that got discovered and shredded by a black bear in the Tennessee mountains---


Here is another pad eaten by a bear.


I rarely resupply on my trips but a couple years ago I decided to place two bearvaults out in the area I was backpacking and dangit if a black bear didn't discover them and gnaw. He rolled both down a hillside and away from my cache site but never got into them. Next to the vaults I had an emergency Thermarest buried and he returned in frustration and ripped it apart.

True. And you can never have too many pics of a tent set up in the snow---