Improving R-Values for Consumers

Thanks for this, Rex.

Excellent idea! I’d go even further and recommend adding 5-10 degrees to a bag or quilt if someone is a side sleeper and is using an air-only mattress.

Having gone through ASTM F3340, I do not believe the test appropriately addresses how the density of a pad will impact its resistance to heat flow. (This is why ccf pads are consistently and continuously recommended for cold weather use, at a minimum to supplement an air-only mattress.)

Roger Caffin address this in his pad review years ago, and it still doesn’t seem like the industry is listening.

Can anyone point me to a good source for a thin, light weight closed cell foam layer/pad that I can use under my pad to add a little extra warmth/ temperature insurance to the pad?

https://www.gossamergear.com/products/thinlight-foam-pad

Similar thin pads from Mountain Laurel Designs in 1/8 inch and 1/4 inch:

https://mountainlaureldesigns.com/product/goodnight-eva-1-8-foam-pad/

https://mountainlaureldesigns.com/product/1-4-foam-pad/

Variety of sizes and thickness from Alps Mountaineering, some on sale at REI:

https://www.alpsbrands.com/alpsmountaineering/products/pads/foam-mat

And if you trust Amazon or other Wild West marketplaces, you can find many others. Very few advertise even approximate R-values, making selection tricky.

— Rex

It has always bugged me when people say a particular pad is good for a particular temperature – it depends on your sleeping bag and other things

Your proposal addresses that, good idea

Now, if manufacturers adopt this I’ll be surprised : )

Good topic & good idea.  As I get back into backpacking, seeking & sourcing a light/UL kit enabling me to hike the mountains I love, I’m finding it difficult to find pad+quilt solutions that carry a substantial enough R-value.  Very few (especially wide/comfortable) pads test over R=4, especially with decent weight. (example: the Sea to Summit Ether Light is loved by many, including Philip Werner, whom I respect, at Section Hiker, but comes in at only 3.2(R) with the new testing.  The Nemo Alpine is interesting, but largely out of stock – & as I said, the choices at 4.8+ are few (I understand the Thermarest X-Therm is not the most comfortable).

And the thin pads (i.e. Gossamer & MLD), while very versatile in use case, offer VERY little bump in R-value (.4, .8, etc), while adding substantial weight & even more substantial volume.  What would be the ‘from scratch’ best practice purchase given these issues?  A Sea to Summit Ether Light Insulated plus a CCF like Nemo Switchback (more weight & volume) or a 4.5+ (R) plus nothing?  I’m working on my big 3 right now, & looking TT DCF shelters which produces a new host of challenges fitting the wide pads (& height) in the Notch Li, Aeon Li, etc.

My original plan was/is to cut weight significantly on everything but pad & quilt – insuring my warmth.  The super thin foam mat additions don’t seem to move the needle.

Given all the experience on this forum, it would be interesting to see what solutions cold sleepers with quilts that like wide pads use.  Thanks for this relevant dialogue.

Steve,

S2S is apparently coming out with an “extreme” version of the Ether Light that will weigh 720 grams in the men’s regular and have an ASTM R-value of 6.2. The large/wide version weighs 950 grams.

Unfortunately my proposal for presenting R-values won’t work with today’s standards and tests. Turns out the ISO 23537 standard, or EN rating, isn’t accurate enough for the sleeping pad tests outlined in the story. I don’t know how REI derived those slightly confusing numbers.

To bad. For now, plan on sleeping colder than your sleeping bag rating unless your sleeping pad is R-4.8 or higher, or multiple layers (e.g. inflatable plus foam) add up to 4.8 or more.

— Rex