Sleeping pads

[Jacko]

As temperatures have stated to decline I have started to think about resolving a dilemna of mine for winter camping. Wht is better insulation Therm-a-rest type pad or the fold up foam type. Also i need to consider weight. I have used the Therm-a-rest for several years and see they are rated frm R3 to R5 but have a nagging suspision than the foam solution may have a more effective R value - depending upon the type ofcouse. Any personal experiences in this?

 

[Kevin Rooney]

I can't say with certainty which is the better insulator. However, for me, it's a moot point as I use one of each when camping on snow and ice. Put the Thermarest down first, then the closed cell (I know - that seems counter-intuitive, but most people - including myself - find that warmer).

Edit: The warmest closed foam pad I've found is made of Evazote (I think I've got the spelling correct). Got it from MEC about 10 years ago, but I think they still carry them. They're a little thicker/heavier, but if you get a 3/4" length it comes out the same weight-wise as the department store closed foam. It is very rugged.

 

[Rick]

Ditto on Kevin's comments. I use my old orange thermarest and a ridge rest underneath it (OK, So I am a little backwards )
I like the absolute security of always having a pad that won't deflate as well as the compactness of a self-inflating pad.

 

[DougPaul]

I use a closed cell pad and a self-inflater. I've always used the self-inflater on top--never tried the reverse.

Only Cascade Designs seems to publish R-values:
R ..... oz
2.3 ... 13 ... prolite 3 short, 47x20x1
2.3 ... 20 ... prolite 3 reg, 72x20x1
3.2 ... 17 ... prolite 4 short, 47x20x1.5
3.2 ... 24 ... prolite 4 reg, 72x20x1.5
3.8 ... 21 ... trail lite, short, 47x20x1.5
3.8 ... 32 ... trail lite reg, 72x20x1.5

3.1 ... 19 ... RR, 72x20x.75
2.6 ... 14 ... RR, 72x20x.625
2.2 ... 15 ... Z-lite, 72x20x.75

Doug

 

[sardog1]

Insulation values for all Therm-a-Rest mattresses (both closed cell and self-inflating) appear on the packaging and at Therm-a-Rest.com. Unfortunately, you'll need to look at each mattress, as there is no online comparison chart on the site.

And as the Therm-a-Rest folks state, "Some people sleep colder than others, and many snow camping pros prefer to sleep with a RidgeRest or Z-Lite under their self-inflating mattress for increased warmth." Personally that's the way I've always done it.

My untested hypothesis is that putting the circulating air in the self-inflating mattress next to the ground increases heat loss, through convection in the mattress. If the mattress is sandwiched between closed-cell and my body, I think it reduces the heat loss that might occur through the self-inflating one. YMMV.

 

[Kevin Rooney]

My untested hypothesis is that putting the circulating air in the self-inflating mattress next to the ground increases heat loss, through convection in the mattress. If the mattress is sandwiched between closed-cell and my body, I think it reduces the heat loss that might occur through the self-inflating one. YMMV.

Try testing your hypothesis, sardog1, and put the mattress on the ground. Most find that combo warmer - and like you, I was rather skeptical until I tried it. I didn't believe it either when I first read about it. It is possible to teach old fharts new tricks.

 

[Jacko]

So we have agreement that a combination works well. In exactly what order needs some experimenting. I guess that will require a few more weeks fortunately.

I have come across the Exped Downmat which is rated at R8.0 and weighs in at 1.2g it is filled with goose down as well as being inflated. It sounds like a good weight and warmth combination but I know of no one who has used it or if it compares favourably to the combo techniques taked about here. I am a little suspicious of a technology that uses down - warm but only when dry - since it is infated this could be a chink in the armour.

As a comparison the best Therm-a-Rest rates at R5 and 1.080g

 

[sleeping bear]

Personally, I'd stay away from the down. I always blow some more into my thermarest for added firmness, which adds moisture. I've actually had it freeze closed, and was then forced to inflate the thing manually, and slowly.

I too am a fan of the two pad combo, and I like my closed cell foam on the bottom. I've not tried it the other way because it seemed like it wouldn't be as warm. However, with the thermarest on the bottom, you may run the risk of it getting damp (especially if you're in a quinzee) and then freezing later.

If you really want to go warm and techie, thermarest just came out with a heated pad. It takes four AAs and starts getting warm when the temp drops below 68, and takes it back up to 70 something. Or stick a nalgene full of boiling water between your legs (cap on tight!) at night- you'll dream you're in a sauna.

 

[DougPaul]

Or stick a nalgene full of boiling water between your legs (cap on tight!) at night- you'll dream you're in a sauna.

I have had to forceably eject said nalgene because it has made me too hot on an otherwise fairly warm night...

Doug

 

[Pete_Hickey]

Personally, I'd stay away from the down. .

I'm curious, why?

The idea behind the goose down, is to prevent the air in the inflatable part from moving as much, reducing convective losses. I have no experience, but the theory sounds good to me.

 

[teejay]

I have come across the Exped Downmat which is rated at R8.0 and weighs in at 1.2g

I wish it were true. The two Exped mats with R ratings of 8.0 are 940g (~2.1 lbs.) and 1260g (~2.8 lbs.). Not bad, though, for mats over 3" thick.

http://www.trailspace.com/gear/exped/downmat/

teejay

 

[DougPaul]

I'm curious, why?

The idea behind the goose down, is to prevent the air in the inflatable part from moving as much, reducing convective losses. I have no experience, but the theory sounds good to me.

My take on it is that over time the down would tend to get wet from the moisture in your breath and since it is in an airtight (and presumably watertight) compartment, the down would get wet and be very difficult/impossible to dry. If the shell material is the slightest bit permiable to mosture, your warm damp body would also tend to drive moisture into it at night. Using an external pump rather than your breath to inflate it would help. By comparison, the self-inflater does most of the inflation on its own and only a few (if any) breaths are required to finish the inflation.*

The second risk is the classic air mattress risk: if it develops a leak, you have no useful insulation. At least there is some insulation left with a leaky thermarest (or equiv).

The above is purely my conjecture--haven't tested it or seen any tester reports examining these issues.

* I have several Thermarest self-inflaters of various sizes and weights, etc. The solid foam ones (heavier, pack larger, and more insulation for the thickness) self-inflate totally but the ones with holes in the foam (lighter, pack smaller, less insulation for the thickness) require a few puffs to inflate to full thickness (discovered after a cold night or two...). Looks to me like an all too common trade-off--smaller, lighter, and more expensive for less performance.

Doug

 

[jbrown]

Using an external pump rather than your breath to inflate it would help. By comparison, the self-inflater does most of the inflation on its own and only a few (if any) breaths are required to finish the inflation.*

The Exped down mats have a stuff sack that is used like a bellows in order to inflate the mats so as to avoid the introduction of moisture.

 

[rambler]

Here is what Kevin R. is talking about:

Gossamer Gear, click on "Sleeping" to find Evazote Pads

www.gossamergear.com

and MEC (Mountain Equipment Co-op in Canada)

www.mec.ca

"Zotefoam Evazote Bivy Pad"

 

[sardog1]

Before you buy an Exped with down in it, try deflating it and getting it back into its bag. Have someone record your time and the diminishing quality of your vocabulary as that time passes. Then think about doing that at -20 some morning, while your feet slowly turn numb. Nope, not for me.