Foam under or over

[Rightfoot]

Heading out this weekend to Red River Gorge. Over night temps in the low teens. I have a neo aire and ridge rest foam pad. Total R value is 6.2. Should I put put the foam
pad under the neo aire or on top.
regards,
Rightfoot

[egilbe]

Depends on who you ask. I prefer foam on the bottom, but others will disagree.

[Shutter]

Wouldn't it make most sense to lay directly on whichever has the highest R value? Highest R value on top, lowest R value on bottom.

[Dogwood]

This weekend at RRG light winds 5 mph, no rain, night time lows at 14*. If it rains tonight(50%) and snow/showers Thurs(60%) ground will likely be damp. I'd be cowboy camping which I really enjoy particularly in cold temps. Mylar ground sheet, 1/8-1/4 CCF, Womans NeoAir, Katabtaic 15* Sawatch quilt or FF 20* Swallow UL. With the Sawatch I likely wouldn't need the CCF. Foam pad would be under the NeoAir Xlite Womans.

You have the R value needed if you are sleeping in an enclosed tent on the ground with a 15-20* sleeping bag with an accurate temp rating so no need for the mylar. I don't see a world changing difference to warmth with that being the case where your pace the CCF pad. Personally, I like the inflatable to the top under this scenario to warm the air inside it without a restless missing turning sleeping position. Maybe, if you toss and turn and are a side sleeper the CCF can go on top.

No wrong or right just my opinion. I think you'll be fine either way. Do what's most comfy for ya. Enjoy the RRG with some light snow. Sleep on the edges of the escarpments. With the leaves off the trees and partially cloudy but occasional clearness the night should be gorgeous for cowboy camping.

[T.S.Kobzol]

Foam on top

[Dogwood]

Foam on top

Is that when you're hanging or even when on the ground?

[nsherry61]

On the ground, at least when it is below zero, I find foam on top to be noticeably warmer. Like, a lot warmer. I don't know why.

I'd rather put the CCF underneath. It seems neater and more stable and better looking, and more logical and, and, and, BUT it's warmer on top, at least when it is really cold and you're pushing the temperature limit of the pad system.

[Tipi Walter]

On the ground, at least when it is below zero, I find foam on top to be noticeably warmer. Like, a lot warmer. I don't know why.

I'd rather put the CCF underneath. It seems neater and more stable and better looking, and more logical and, and, and, BUT it's warmer on top, at least when it is really cold and you're pushing the temperature limit of the pad system.

I agree with this and TS Kobzol---foam on top. But why believe us---just do it both ways and see for yourself.

[SWODaddy]

An air pad is more susceptible to heat transfer via convection with the cold air, whereas a CCF pad is more susceptible to heat transfer via conduction with the cold ground (think I got the terms right, but you get the point).

Short answer: foam on top.

[Dogwood]

On the ground, at least when it is below zero, I find foam on top to be noticeably warmer. Like, a lot warmer. I don't know why.

I'd rather put the CCF underneath. It seems neater and more stable and better looking, and more logical and, and, and, BUT it's warmer on top, at least when it is really cold and you're pushing the temperature limit of the pad system.


I agree with this and TS Kobzol---foam on top. But why believe us---just do it both ways and see for yourself.


Now we get top the place where a mixed under insulation system with an inflatable pad in the mix and the inflatable psssts you just lost your major R Value pad if the inflatable is next to ground with the CCF on top. This could have been prevented if the CCF was on the bottom. NOT GOOD losing your main insulation in 14* temps?

That's why I said and I ask how are you sheltering if at all...tent, hanging, cowboying, groundsheet?, type of ground, quilt, sleeping bag. temp rating of either the bag or quilt in regards to the lowest environmental sleeping temp...

[Dogwood]

An air pad is more susceptible to heat transfer via convection with the cold air, whereas a CCF pad is more susceptible to heat transfer via conduction with the cold ground (think I got the terms right, but you get the point).

Short answer: foam on top.

And what happens if the OP is cowboy camping? What happens if no groundsheet is being used? Do you still suggest laying the higher R Value Neo Air inflatable directly on the ground risking deflation? It happened to me on a Sheltowee Trace Thru-hike having a very cold night only on a 1/4 CCF pad using a quilt that was 5* rated above the minimum night time temp. Shivered most of the night despite wearing everything I had and putting my knees to feet in my empty backpack.

[nsherry61]

An air pad is more susceptible to heat transfer via convection with the cold air, whereas a CCF pad is more susceptible to heat transfer via conduction with the cold ground (think I got the terms right, but you get the point). . .
Right or wrong, it sounds great. I'll run with it. Now we know. Thanks!


And what happens if the OP is cowboy camping? What happens if no groundsheet is being used? . . .
So, use a friggen ground sheet. Duh.

[Dogwood]

Duh? Doo da da.:confused:

You're missing the point. Does the CCF pad under the Neo Air give it greater or less protection from deflation? Could this be important if the main R Value component in the under insulation is the R Value of the inflatable pad?

[jellyfish]

An air pad is more susceptible to heat transfer via convection with the cold air, whereas a CCF pad is more susceptible to heat transfer via conduction with the cold ground (think I got the terms right, but you get the point).

Short answer: foam on top.

Science the heck out of this problem. Love it.


Sent from my iPhone using Tapatalk

[rocketsocks]

The way it was explained to me and the way I remember it is the small indents in the ccf pad take less energy to heat up when coverd by a layer (ie; person in bag) than the larger volume of the air mattress below...but I don't mind saying that after reading this thread...I'm more confused than ever :D blinded by science :cool:

i put my my ccf on top

[Engine]

Depends on who you ask. I prefer foam on the bottom, but others will disagree.

+1 Bottom protects pad, stops slipping, adds same R value. (but in all fairness to the put it on top folks, I haven't tried it with my current 1/8" GG pad)

[T.S.Kobzol]

Is that when you're hanging or even when on the ground?


Ground. From experience, and I did try it both ways.


Coincidentally also in a hammock as the bottom quilt is always under the hammock and I slid the foam in the double sleeve. I have never tried inflatable pad in a hammock and probably never will...doesn't seem to make sense to me.

[Tipi Walter]

One caveat with foam pads---These things are bulky and usually placed on the outside of the pack whereby they occasionally pick up thorns from briars or hawthorn trees or whatever else. These spikes break off into the foam and are invisible. THEN when you sandwich your inflatable with the foam the thorn pokes out and punctures your beautiful inflatable. It can happen. CCF's act like pin cushions . . . at times.

[Starchild]

Ever sleep on a foam mattress or a mattress with a foam topping, it is very warm. Air mattresses are colder than normal mattresses.

[SWODaddy]

And what happens if the OP is cowboy camping? What happens if no groundsheet is being used? Do you still suggest laying the higher R Value Neo Air inflatable directly on the ground risking deflation? It happened to me on a Sheltowee Trace Thru-hike having a very cold night only on a 1/4 CCF pad using a quilt that was 5* rated above the minimum night time temp. Shivered most of the night despite wearing everything I had and putting my knees to feet in my empty backpack.

The context of the question was clearly heat retention. My answer was appropriate in that context, so I don't know why you're trying to quibble over "what if" scenarios. Nobody here needs lectured on the fact that a foam pad is more durable than an air pad, that's obvious.

[Dogwood]

Ground. From experience, and I did try it both ways.


Coincidentally also in a hammock as the bottom quilt is always under the hammock and I slid the foam in the double sleeve. I have never tried inflatable pad in a hammock and probably never will...doesn't seem to make sense to me.

Thanks for answering. You also answered what I was thinking, "how do you use a CCF and inflatable in a hammock." You place the CCF in a sleeve. The CCF on top of an inflatable in a hammock , which I tried a few times quickly abandoning that approach, has me feeling like I'm on a skateboard on ice in hammock with all my tossing and turning and side to to side sleeping. Nothing stays under me. :)

[Dogwood]

Right or wrong, it sounds great. I'll run with it. Now we know. Thanks!


So, use a friggen ground sheet. Duh.

Respectfully, many use a CCF pad so they don't have to use a groundsheet.

One of the advantages of CCF verse open celled foam like a many of the Yoga type mats is they don't sop up H20 like a sponge. water.

[swisscross]

+1 Bottom protects pad, stops slipping, adds same R value. (but in all fairness to the put it on top folks, I haven't tried it with my current 1/8" GG pad)

The GG pad becomes a mangled mess when place on top of an air pad.
I guess I move around too much during the evening.
Placed under the air pad it stays put. Not sure how much warmth it actually adds.
I take it anyway as a sit pad and to keep my main pad from skating around the tent.

[Dogwood]

One caveat with foam pads---These things are bulky and usually placed on the outside of the pack whereby they occasionally pick up thorns from briars or hawthorn trees or whatever else. These spikes break off into the foam and are invisible. THEN when you sandwich your inflatable with the foam the thorn pokes out and punctures your beautiful inflatable. It can happen. CCF's act like pin cushions . . . at times.

Good point. Cockle burrs, Jumping Cholla, Prickly Pear cacti included in the desert. Burdock and thistles too.

[Dogwood]

The GG pad becomes a mangled mess when place on top of an air pad.
I guess I move around too much during the evening.
Placed under the air pad it stays put. Not sure how much warmth it actually adds.
I take it anyway as a sit pad and to keep my main pad from skating around the tent.

It certainly does for me too as I toss and turn AND tend towards using the thinner thickness CCF pads of 1/8 to 3/8.

No right or wrong. Not pushing anything. Situations and usage varies.

[Obiwan]

I would put the foam on the bottom since it is less prone to punctures. I have also done the same thing with my clothes in early fall cold snaps at altitude and it worked well even with the first gen neoair

[Deadeye]

Whatever, just be sure to take the approach trail.

Foam on the bottom, if only to protect the inflatable. R-value of the combined pads shouldn't be materially different in either order.

[Don H]

Rightfoot, If your Neo-Air is an Xtherm model then it's designed to reflect body heat back onto you. Using a foam pad on top would interfere with that.

I always put the pad on the bottom.

[cmoulder]

Try it both ways and find out for yourself.

I find CCF on top much warmer.

The 1/8" GG CCF pad does indeed get mangled up if on top, but a 3/8" CCF will retain its shape.

It also helps greatly to have some elastic loops to hold the air mat and CCF together.

[Slo-go'en]

Since I adjust the air pressure in my NeoAir to conform to my body, ie, let my butt dip into it, I'd put the pad under. Under chilly conditions, my butt is the first part of me to start feeling cold due to it being a bit closer to the ground. Putting just a 1/4 length of CCF under that area is a big help.

[MtDoraDave]

Would it make that much of a difference to have one on top versus the other? I don't know about the difference in felt R value, but the comfort of having the inflatable on top is why I would do it that way.

Last November, it was in the teens or low 20's, and I only had my prolite plus. Risky not bringing a ccf, but it is what it is - it didn't get punctured, and I was quite warm each night. Perhaps if a person is under equipped as far as bag/quilt temperature rating, it may make a difference.

[Leo L.]

Ground. From experience, and I did try it both ways.


... I have never tried inflatable pad in a hammock and probably never will...doesn't seem to make sense to me.

I've never camped in a hammock and propably never will, but I very much like to take a noon break including a nap in the hammock which hangs in the loft.
I store my Thermarest inflated spread out in this hammock and find it really great for this nap.
The weight of my body seems to increase the air pressure in the mat a bit thus spreading it to its full width, so the side rims of the hammock don't press to tight to my sides (a feeling of being too much enclosed I would not like).
So up to my very limited experience with hammocks, an inflatable adds a lot of comfort to it.

[T.S.Kobzol]

We maybe drifting from the original post but ... Interesting use of inflatable to get greater comfort. I already assumed my hammock is super comfortable and the undwequilt isonky for warmth. Adding foam pad is only in extreme cold for me and I think it is mostly mental insurance ;)

[Pringles]

Since some have commented about a pad deflating... I've assumed that whatever warmth value the pad has is retained even if it is flat as a pancake, that whatever material made it have an r value is still present and working. But since we're talking about this, am I correct, that the r value is retained even when the pad isn't inflated?

[Leo L.]

In an inflatable mat, the air is the most important factor of insulation.
Once flat, the only insulation present comes from the shell, which is near to nothing.

[cmoulder]

But since we're talking about this, am I correct, that the r value is retained even when the pad isn't inflated?

Totally not! :)

[nsherry61]

Would it make that much of a difference to have one on top versus the other?. . .
No matter how counter-intuitive it seems, it can make a big difference. BUT, it only matters if it's cold enough that doing it the other way isn't warm enough.

[cmoulder]

No matter how counter-intuitive it seems, it can make a big difference. BUT, it only matters if it's cold enough that doing it the other way isn't warm enough.

True. I tested at -5°F.

Zero doubt, CCF on top was warmer. By a lot.

[Tipi Walter]

Excellent opportunity to test it in the next 4 days.

[Rightfoot]

Couple of inches of new snow falling today and the temps are supposed to drop. I've got Friday and Saturday night to try both methods. The original question drifted a bit to cowboy camping and hanging but I will be in a Mountain Hardware Trango 2 tent with a tried and tested 0 degree goose bag. Should be a fun weekend. Thanks for everyone's input. I'll repost Monday with my findings.

[HooKooDooKu]

Wouldn't it make most sense to lay directly on whichever has the highest R value? Highest R value on top, lowest R value on bottom.
No, because R-value is cumulative.

However, there are three forms of heat transfer: Convection, conduction, and radiation.
R-value is only a measure of resistance to conduction.

But how warm you feel is going to be based on how the pads handle all three forms of heat transfer.

So while I don't KNOW why some are claiming a CCF pad on top of an air pad feels warmer than the other way around, I see that as a possibility if the CCF pad does a better job at reflecting radiated heat than the air pad. All other things being equal, having the pad that best reflects radiated heat closer to your body would make sense as the arrangement that keeps you warmer.

But there's all sorts of things that might be coming into play. Air that can move is a poor insulator... and from what I've seen of the neo air, the baffles are open from side to side. In other words, a neo air likely has two R-values associated with it... one for how well it resists the transfer of heat from the ground to your body, and another R-value for how well it resists the transfer of heat from the air surrounding the sides of the pad to your body. It's quite possible that a CCF pad does a much better job as resisting heat transfer from the surrounding air, and therefore having a CCF pad on top of an air pad will insulate you to some degree from the side-ways heat transfer of the air pad.

So you really need to know more than just R-value to know how a pad is going to work for you... and every pad is going to be different as it relates to conduction, convection, and radiation.

Since every type of pad in a manufacturer's lineup is going to react to these three modes of heat transfer differently, and those modes are affected by your setup (hammock, ground, tent, tarp, etc)... the only real answer that can be given is that each person simply must try both ways and see what works better for them in there conditions.

[Kaptainkriz]

Indeed, and may even have a little snow on the ground. Looking forward to having fun.

Excellent opportunity to test it in the next 4 days.

[Kaptainkriz]

Well, it was somewhere around 9F last night just South of Manassas Gap. I tented at the Jim and Molly Denton Shelter. I had a Z-Light and an XTherm under a barely adequate Cosmic 21 Down bag. It was definitely warmer with the foam on top and the air on the bottom. That configuration did lead to a lot of sliding but was warm provided I wore a couple layers and a hat. One thing that also contributed to warmness was a Sea to Summit Aeros Pillow. The pillow really helped to keep my head toasty warm. I had not over-nighted in temps that low before. Stuff I learned: My hands froze quickly while setting up the tent and cooking outside. Mittens and a Zippo hand warmer made for quick recovery. I'm glad I took I think Tipi's advice and filled my pots with water the night before. Everything in the tent not with me in the bag was frozen solid. Pot was ready to cook in the AM. The copper strip trick enabled my canister stove to perform very well. The metal toilet seat at this shelter is a cruel hoax!
378183781937820

[Venchka]

Interesting. Night before last I was in my tent in the backyard and the temperature dropped to 12 in the wee hours of the morning. Xtherm Large and WM 20 degree Alpinlite Long. Once I got through experimenting with various bits of clothing I slept well.
Obviously the Cosmic bag is rated better than advertised or you are a very warm sleeper. Either way it's good.
Wayne


Sent from my iPhone using Tapatalk

[rocketsocks]

Well, it was somewhere around 9F last night just South of Manassas Gap. I tented at the Jim and Molly Denton Shelter. I had a Z-Light and an XTherm under a barely adequate Cosmic 21 Down bag. It was definitely warmer with the foam on top and the air on the bottom. That configuration did lead to a lot of sliding but was warm provided I wore a couple layers and a hat. One thing that also contributed to warmness was a Sea to Summit Aeros Pillow. The pillow really helped to keep my head toasty warm. I had not over-nighted in temps that low before. Stuff I learned: My hands froze quickly while setting up the tent and cooking outside. Mittens and a Zippo hand warmer made for quick recovery. I'm glad I took I think Tipi's advice and filled my pots with water the night before. Everything in the tent not with me in the bag was frozen solid. Pot was ready to cook in the AM. The copper strip trick enabled my canister stove to perform very well. The metal toilet seat at this shelter is a cruel hoax!
378183781937820i guess I missed it, but what is "the copper strip tip"?

[Kaptainkriz]

This one: http://www.whiteblaze.net/forum/showthread.php/115424-How-low-will-a-cannister-go!

i guess I missed it, but what is "the copper strip tip"?

[Engine]

Spent the night outside on Saturday and used my normal setup with a 1/8" GG pad on the bottom, the Nemo insulated mummy Tensor inflatable, and my EE 20* quilt. It only got down to 29* and I had to stick an arm outside the quilt a couple times to shed some excess heat.

In the morning, after being outside of the tent for about 90 minutes I went back to pack it all up. By then the top of the inflatable felt pretty chilly to the touch, but when I put my hand between the pads I was surprised by how warm it still was there, especially compared to the floor of the tent which was quite cold. It's amazing to me that just 1/8" of evazote can provide that level of extra insulation.

[Rightfoot]

Had a great weekend other having to depend on a rolling start to get the old diesel truck to start Sunday morning... It was down to 9 degrees Friday and 5 degrees Saturday night, both nights with a light breeze. I went foam on bottom the first night and slept well. The second night was foam on top and I believe I slept even warmer. The major problem with foam on top was staying on top of the pad without sliding off although this can be fixed with a little creativity. Thanks for all of the ideas, especially to Tipi for the water in the pot idea. As Kaptainkirz said above it worked great.