R-value of sleeping pad vs. subjective temp

I'll just quote what I've said before on the subject:

No pad is "too hot"–they're only more efficient. Basically, both a three-season and winter pad have the insulation to keep you at very, very similar levels of warmth (to the point that you won't notice a difference) at 50 degrees F. However, you might notice a difference, depending on R-value, at 30 degrees F. At 10 degrees F, the winter pad only has the insulation to keep you warm.

Basically, they both lose heat to the ground so slowly that at higher temperatures (e.g., summer) they are functionally the same. At lower temperatures, the three-season pad loses heat to the ground too quickly to keep you similarly warm.

FYI, I use an XTherm year-round. It was the 70D bottom and simplicity of having one pad that convinced me.

It isn't subjective whatsoever. Clayton is exactly right.

Here's a link to a similar thread on the subject:

http://tinyurl.com/qjkd9h9

I might add that there are too many variables to simply assume that all pads with the same advertised "R" value are actually going to perform the same, especially when it comes to all the inflatable mattresses on the market.

The temperature of the air, the temperature of the ground, ones body weight, how one sleeps on the pad, the dew point; all these things affect how the air in those mattresses will behave, thus affecting the pads so-called "R" value.

Closed celled foam pads are likely to be more consistent with their R values than anything else we rely on. That's why they are always recommended for winter.

If you like the comfort of an air mattress but think you need more insulation, no harm with supplementing with a closed celled pad.

I find if my pad is inadequate I can easily feel the cold originating there. That is if sleeping on my back my back gets cold first. Once chilled it seems harder to tell. As a cold sleeper I switch from my neoair to my xtherm around 35-40F depending on weather reports. Had I bought the Xtherm first I may have just used it all year round as Clayton.

I also find a little moisture can reduce my body temp considerably. Last trip after hiking in moist air all day my LS shirt was moist and I was slightly chilled before bed so I put on my rain jacket and then wore it to bed in an attempt to trap some more body heat and dry my worn shirt. My shirt dried out shortly and I ditched the jacket before sweating and it worked nicely. At that point I was dry warm and needed to vent to avoid getting into the same situation. I seem to do better a little on the cooler side rather than get into a situation where I am producing even small amounts of moisture as the temp drops.

jimmyb