R-Value/Temperature Rating Comparison

[GadgetUK437]

I was struggling to compare pads, what with R-values and temperature ratings.
Luckily the Exped site puts both on the specs of their pads, so I made a chart.
Thought I would put it up here just in case anyone else might find it useful.

[theclark5]

Thank you. Was just looking into this today!

[SilvrSurfr]

Just keep in mind that R-value is for when the pad is used on the ground. To my knowledge, those ratings don't apply when you're suspended in the air.

[Drybones]

Just keep in mind that R-value is for when the pad is used on the ground. To my knowledge, those ratings don't apply when you're suspended in the air.

Or in a shelter, I've slept comfortable in a tent at 15* on a 3.5 R pad wearing only boxers...froze my butt off in a shelter at about 25* with the same gear and a down jacket on...got cold from the bottom.

[Shug]

Thanks for this.....good to have on record. Got a couple pads for my Amok and now I know I can get on down there.
Shug

[TominMN]

Just keep in mind that R-value is for when the pad is used on the ground. To my knowledge, those ratings don't apply when you're suspended in the air.

R-value is r-value. Suspended or on the ground. But I agree that the temperature ratings for a pad on the ground aren't valid for hammock use.

[HillbillyHanger]

I agree. R value is a measure of a materials ability to restrict heat flow. On the ground, you fight conduction. In the hammock or on a raised shelter platform with air gaps you fight conduction and convection heat loss.

[TominMN]

... and maybe more than a smidgen of radiative.

All this raises an interesting question when it comes to temperature rating of a pad because it seems that the manufacturers are taking into account air temp and not ground temp, but I could be making a gross assumption. Regardless, I suspect the average reader of that chart is thinking air temp.

Ask a ground sleeper about sleeping on frozen ground with air temp in the 50s.

[millergear]

Some data I gleaned from Dave Womble (and/or Ed Speer) many years back specifically for in a hammock. My tests showed them to be right on. BUT, everyone is different! And not all Pads have them same R Value per inch.

Pad Thickness R-value Temperature
(in.) (deg. F)
0 0.00 70
1/8 0.54 63
1/4 1.09 57
3/8 1.63 50
1/2 2.17 43
5/8 2.71 37
3/4 3.26 30
7/8 3.80 23
1 4.34 17

[TominMN]

That's just it. Temperature rating for whom?

And r-value per inch variability has probably mushroomed with all of the pad options these days.

Still, something that one can use as a starting point for reference could be useful...