Hi People,
Looking for some info regarding Sleeping pad R-Values and cold weather comfort. I'm going to upgrade from my Ridgerest because I just can't stand it anymore. I was looking at a BA Insulated Air Core, thinking that it would be warm enough, but then saw Richard Nisley's comments here:
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=5687

In that thread, Richard mentions that the BA Air Core actually has an R-Value of 1.8 (as opposed to the advertised 4.1). Also, the chart seems to indicate that you need about an R4.5 to get down to 35 degrees and something at about an R6.5 to get down to about 15 (my target low temp). Also, an uninsulated air pad (R1) appears to only be good for about 72 degrees.

I'm skeptical of this data, because I'm a cold sleeper and have comfortably taken my ridgerest about 15 degrees colder than I should be able to. Or perhaps more appropriately, I'm skeptical that the R-Value performances are the same for pads as they are for sleeping bags.

Based on this info, I have some follow up questions:
-have there been any updates to how r-values translate to pad performance?
-Are the newer BA Insulated Air Cores still in the upper 1's?
-How low can a person typically take an R1 pad (air mattress)?

Thanks!

Measured R-values for a large number of pads can be found here

The BA Air Core and BA Insulated Air Core are two quite different pads!

Check the State of the Market report series on sleeping pads that BPL issued last August:

http://www.backpackinglight.com/cgi-bin/backpackinglight/airmat_sotmr_part1_2011

https://www.backpackinglight.com/cgi-bin/backpackinglight/airmat_sotmr_part2_2011.html

Note especially that the tested R-value varies widely with the amount of inflation. If you inflate your pad fully (assuming you can stand to sleep on that hard a surface), you'll get the highest R value. If you like your pad really squishy (as I do), the tested R-value will be quite a bit less. Probably the average R-value shown in the ratings is as close as you'll get to real-life use.

Clearly, individuals differ as to how much insulation they need underneath. However, I have read that the EN13537 tests of sleeping bags specify a mat with R-value of 5 for a 20*F/-7*C sleeping bag. I haven't been able to confirm this, but it's pretty much what I've found from experience.

From Part 1 of the above cited SOTM article: "If you must have an answer for a winter mat, a minimum R-value of 5 would be a good starting point. Below that and you may have some problems, depending on how you sleep and other conditions as outlined above. A mat with an R-value above 6 should be fairly reliable, even comfortable. Note that what a mat offers does seriously depend on how thick it is in the field, and this is a major topic for Part 2."

Then, of course, there's the difference between frozen ground and snow (the latter is usually warmer once your body heat goes through the pad and starts to melt it).

Also check Mark Verber's encyclopedic website (page down to the sleeping pad section):
http://www.verber.com/mark/outdoors/gear/sleep-system.html

Kier---I lost interest and couldn't stand my Ridgerest in 1984 and never went back, due mainly to comfort and warmth. Throw one on a sheet of ice and you'll quickly understand. In the years since I've been thru every conceivable Thermarest and the Prolite Plus has become my go-to three season pad and the Exped Downmat my winter pad (at 8R---very nice).

Thanks for the wealth of info!

I had no problems sleeping on a ba iac at 40 sans clothes. I would assume I could easily go lower with clothing. However, I am not a cold sleeper. A buddy of mine who was a very cold sleeper was also able to sleep on a ba iac with minimal clothes (maybe none, we were in separate tents), but just barely. He said the pad felt a little cool.

Thanks Larry. The whole reason I'm looking at the BA IAC, beyond 2.5" of comfort, was thinking that I'd have one pad for solid three season use. But in order for a pad to fit 3 season use, it needs to be able to stay comfortable down to 20 degrees or so. I guess I could take along my ridgerest to layer on top of it, but I'm trying to keep this simple and relatively light. I'm willing to pay the 6oz penalty in the summer if it would pay off with a 10oz penalty in the spring and fall (by skipping two pads).

hmmm...

Kier,
A couple of weeks ago I used my BA IAC for 2 nights.
The first night it got down to 35 and I was comfortable.
The next night it got down to 25 and I was miserable (very cold).
I've had that pad for years and it's pretty consistent with my prior experiences with it.

Some of that may be attributable to inflating the pad by mouth both nights. I expect the the buildup of moisture did not help.

Thanks John. I'm starting to think that a sub 24 ounce pad that can take me down to 20 or 15 degrees isn't going to happen. I may have to shoot for the BA IAC and accept that in the colder parts of the shoulder seasons I'll have to layer on the ridgerest.

Kier, how about the newly released NeoAir Xtherm? It's a full length pad with an R-value of 5.7 for 15 ounces. Not cheap, but that should be all the pad you need to get to 15 or 20 degrees.

You may want to check these out. I purchased both and will be testing them the 17 th through the 21st. I have slept one night on the allseason and it was impressive.

The Neoair allseason isn't that much more R value compared to the BA IAC, so I was going to have to bring extra ground insulation anyways, so why spend the extra $$$?

However, I hadn't seen the xtherm, and that is pretty impressive. It's a lot more than I wanted to spend, but 15oz for a 5.7 r-value is very nice. That might be the pad I'm looking for and worth saving a few more pennies for.