SIM Lite 3.8

R Value is cumulative so having 2 stacked pads will increase the total insulation. With that 2.2 + 4.x you'd be in the range you'd want to be for those temps. I use an Exped Dura 8 which is 3.5in thick (8.89cm) and works well for backpacking. When car camping I use a Deep Sleep (R9) that is 3in thick (7.62cm). Since both pads in question are about the same insulation value, I'd lean towards the thicker as long as it doesn't compromise your pack size or weight.

Exped is good, several models depending on what kind of camping. For reference I’m 6’ 330lbs. MegaMat/DeepSleep used for car camping. Dura used for backpacking. You may also be able to use furniture foam which would be cheaper and can be cut to different sizes.

Make sure your pad’s R value is ASTM F3340 rated, otherwise it’s just a suggestion. I would want an R value over 6 for winter camping

Yeah, the regular length has been fine for me. If I have some extra room at the end of my tent, I’ll fold up my jacket and lay it down there - keeps my feet from hanging over dead air. Often on colder winter trips, I’ll bring a bivy sack for extra warmth. Sleeping bag and pad go in the bivy sack. No issues then - your feet are in the bivy, and toasty warm

Exped has a 5R version out- just picked one up but haven’t used it yet; I used a 3.5R version in Yellowstone Lamar Valley last September with a Feathered Friends Flicker 20 degree. At age 64 not going back to closed cell foam- just more lunges more farmer walks with dumbbells and more frequent training hikes with loaded pack. I like polyester sleeping pads because if I don’t cover enough ground during the day I do a great job making up for it at night when I’m sleeping and a polyester sleeping pad helps me stay on the pad. Yes it weighs more. So… more lunges…more training hikes…and better sleeps at night on trips. Nemo Tensor used to be polyester but they switched to nylon to market a lighter weight pad.

I was using a backpacking style exped inflatable pad and recently replaced it with a self inflating one. Takes up a lot more space but far more comfortable (and quiet!).

I've had great success with Thermarest, REI, and Exped self inflating mattresses. All have good customer support too. I wouldn't ever bother with an all air mattress. Poor insulation, rotten in cold. Get a FlexTail pump.

I tried long term sleeping on an Exped. They're a seif inflating pad. It did not last a full year. The fabric in those is glued to the foam, and as it turns out tossing and turning can eventually break that bond, and the fabric blister.

Yes. They were going to honor the warranty, but it was less than a year so just easier to drop it at REI where I bought it and get a refund. Definite bummer; great mattress even at home. If they ever do a long lasting home version I'll be all over it...literally. :)

Exped, REI, and Thermarest pads have all lasted that long and more. All self-inflaters.