Best winter Sleeping PAD?

[Rick]

Thanks, but I don't think I was confused:

The ridge rest is 3/4 inch from a flat surface above to a flat surface below (ie total thickness = ridges + foam thickness). (IIRC, the foam thickness is ~3/8 inch.) The primary insulation is in the foam, not the airspaces of the ridges so its insulation value is much closer to the insulation value of a 3/8 inch flat pad than the insulation value of a 3/4 inch flat pad.

The ridges actually reduce the insulation value (by increasing the area for heat loss) but the airspaces created by the ridges are claimed to increase the insulation value. (Of course, the ridges are flattened under body weight which would decrease their value.) One would need the R-value of a flat pad using the same amount of foam to determine whether the ridges actually help or are just a gimmick (and both R-values should be measured with the pads compressed by body weight).

Currently listed on the REI website:
* RR Regular: 5/8 inch, R-value 2.6, 20x72 inches, 14 oz (regular)
* RR Deluxe: 3/4 inch, R-value 3.1, 20x72 inches, 19 oz (regular)
(Don't know if these R-values were measured under a simulated body weight--my guess is that they were not.)
* REI standard blue foam (3/8 inch), R-value ?, 20x72 inches, 8 oz. (Sold as 24x75 inches, 10oz. The above weight is for a pad cut down to 20x72 to match the RRs.)

Thus, 2 REI blue foams would be lighter than, most likely give more insulation than, and would probably pack larger than a 3/4 inch RR. (And, of course, you could carry just one blue foam in warm weather.)

Doug

Wasn't you, DP

 

[DougPaul]

Wasn't you, DP

OK. Thanks.

Hopefully someone will find my analysis useful...

Doug

 

[tb69wemt]

I use the Pacific Outdoor Equipment Hyper High MTN Sleeping Pad and am very , very happy with it.

http://www.backcountry.com/outdoorgear/Pacific-Outdoor-Equipment-Hyper-High-MTN-Sleeping-Pad/POE0069M.html?CMP_ID=SH_FRO001&CMP_SKU=POE0069&mv_pc=r126


search the web I paid about 80 bucks for mine delivered

 

[sardog1]

Wasn't you, DP

I must have had phone foam in my eyes. Sorry for the confusion.

 

[DAYHIKER]

Exped is by far the warmest

Have used the Big Agnes primaloft in the past...not bad but the Exped 9 with Down insulation actually feels like you have a heating pad under your sleeping bag...used it on Isolation at -10 a couple of weeks ago and had to remove my fleece layers I was overheating in my bag. This mat has a built in air pump which you need to master under cold conditions

 

[Billy]

...And anyone who puts the Thermarest on the bottom will be called out --we've been down this path before .

For those who don't know, please explain why. Thanks.

 

[Kevin Rooney]

For those who don't know, please explain why. Thanks.

We've had some lively discussions as to which is the warmer combination - closed-cell foam next to the snow/ice/ground, or the inflatable.

Personally, I'd always put the closed-cell foam down first and it had been an OK combo. Then, someone who had far more experience than I suggested reversing the order, and sure enough, I found I slept warmer with the inflatable down first.

But, like many things in life - what works for one doesn't always work for another. YMMV -

 

[sardog1]

The "closed-cell pad on bottom" theory is based on the fact that air circulates within the inflatable but not the closed-cell pad. Since heat flows from a warm object (your body) to a cold object (the surface of Mother Earth in winter), it seems logical to minimize heat loss from convection within the inflatable by putting the closed-cell pad on the bottom.

However, Rooney's contrary experience could be explained by the idea that putting the closed-cell pad on top spreads the sleeper's weight more uniformly over the inflatable, thus reducing compressed cold spots. Which would of course mean that I don't know what the *&^# I'm talking about when I advise putting the closed-cell pad on the bottom.

Surely there's a physics student out there who needs a project.

 

[DougPaul]

If we assume that the heat conductivity of the two pads is not a function of temperature, the heat flow is proportional to the temp difference across each pad (reasonable 1st order approximations), and the pads are not deformed by any weight on them, then the order does not matter.
Rtot = R1 + R2
(Rx = R-value of x)

In practice body weight will compress both pads, but might also expand unweighted parts of the inflatable. Compression would most likely reduce the local R-value. The weight profile on each pad would depend upon how much air is in the inflatable, the order of the stack, the weight and position of the sleeper, and the shape of the ground underneath. I'm not going to try guess whether the net effect will be to increase or decrease the total, but I suspect that it doesn't make much difference if the inflatable is well inflated and the two pads stay in good contact.

I personally put the closed cell pad on the bottom because it reduces the chance of damaging the inflatable (due to something sharp on the ground) and I assume (without actual testing) that it is more comfortable. Perhaps the edges of the upper pad will stay in better contact with the lower pad as well. You are welcome to stack in whatever order pleases you.

Conclusion: much ado about very little.

If you want to perform some experiments and make some measurements, be my guest. However, IMO, such issues as "are closed-cell phones more waterproof than regular cell phones?" and "do they keep the batteries warmer?" are much more pressing than the stacking order of sleeping pads. Or just sleep on it.

Doug

 

[daxegraphix]

Memo on the pads...

Thanks for all of the information--and schooling. Last night I slept out in the backyard using 2 cheapo closed-cells folded so that I had 3 layers under me from neck to thigh. My pack went under my calves and I cheated and used my home pillow under my head. Here in Albany it was around 8 or 9F with 25-40mph winds and light snow. With my new -20 bag wrapped in my OR supplex bivy bag and this 3 layer cheap foam configuration--I was actually warm the whole night. This is without a tent--the nylon coffin. I'll experiment now with an inflatable and a closed cell just for the heck of it, but this config seemed to work well.
Thanks for the help,
Pete O.

 

[KPMMBM]

sort of related to this thread, if I plan on using my 3 season tent in winter does using or not using the footprint make any difference in insulation value? I know a three season tent doesn't have the structural benefit of a winter tent but I'm not concerned about using a footprint for damage by rocks, sticks, etc in winter. any other concern about using a 3 season tent in winter? most likely not above treeline

 

[sardog1]

The footprint adds nothing to insulation. But you will discover its merits in the morning when you break camp. Without it, your tent floor will be frozen to the snow surface -- or worse, to the ground if there was insufficient snow for insulation.

With the footprint in place, packing the tent is much easier in the morning. You won't need to break off clumps of ice from the tent floor and the tent stays drier. (Water is evil in winter in all its forms, except for traveling on and imbibing.) The footprint can be shaken (not stirred) to relieve it of any ice/snow cladding it acquires.

 

[DougPaul]

Re a footprint:
Just buy some plastic drop cloth (available in a number of thicknesses) at your local hardware store and cut it to match your tent floor. Much lighter and cheaper. Thinner is lighter but less durable--I think I use ~1mil thickness.

Doug

 

[Craig]

Re a footprint:
Just buy some plastic drop cloth (available in a number of thicknesses) at your local hardware store and cut it to match your tent floor. Much lighter and cheaper. Thinner is lighter but less durable--I think I use ~1mil thickness.

Doug

Tyvek can be free if you don’t mind dumpster diving.

Product specs to the right…

 

[Chip]

The footprint adds nothing to insulation. But you will discover its merits in the morning when you break camp. Without it, your tent floor will be frozen to the snow surface -- or worse, to the ground if there was insufficient snow for insulation.

With the footprint in place, packing the tent is much easier in the morning. You won't need to break off clumps of ice from the tent floor and the tent stays drier. (Water is evil in winter in all its forms, except for traveling on and imbibing.) The footprint can be shaken (not stirred) to relieve it of any ice/snow cladding it acquires.

I like to inspect the area under the tent after packing up: The person who melted more snow/ice under the tent was less well insulted from the snow/ice overnight and was probably colder.

I don't use a footprint at all. One thing I have done is to cut 3 Walmart blue eggcrate pads to fit my winter tent floor precisely for full floor coverage. These can be duct taped together in the tent, if you want. Actually only the 2 outside pads needed to be cut, I think. I share these with whoever else will be in my tent that night as our bottom/first pad layer. We then also pack whatever we want to use as our second pad. This system works well to assure at least one full layer of insulation throughout the tent. I also like this system if I'm sharing the tent with a dog, as it guarantees the dog some pad and protects the floor from claws.

If there'll be 3 people in the tent, we each have one of my pieces and our own 2nd pad. If there'll be 2 people in the tent, 1 person carries the full/middle pad and their own pad and the other carries the 2 outside cut pads and their own pad.