I have the original green regular 72" long NeoAir, which I think weighs 14 oz. From experience, I know that I will be cold using it alone if the air temperature is below 35F. I want to be able to go down to 20F as lightly as possible.

I have several options. I have a RidgeRest shorty which weights about 9 oz and Therm-A-Rest Prolite Plus shorty which weights 17 oz for a total of 26 oz. I think this combination would be plenty warm down to 20F, but they are not full length. Both the RidgeRest shorty and the Prolite Plus shorty are 47" long and I am 6' 1", so they are going to extent only to my knees at the most, depending on if my head is on the pad or not. I could then put my backpack, a Granite Gear Nimbus Meridian, below the pads to insulate my lower legs, but the backpack may not keep my calves and feet warm. This system is heavy, but at least the RidgeRest cannot fail.

I could also put my Regular NeoAir on top of the RidgeRest shorty (with the pack below as above) for a total weight of 23 oz. I'm not sure if this combination would be warm down to 20F.

Or I could bite the bullet and buy a Term-A Rest NeoAir All Season regular 72" long which weighs 19 oz (or the smaller medium All Season 66" long which weights 18 oz-not much difference in weight) Supposedly the All Weather NeoAir would be warm by itself down to 20F, at least that's what I've read on some blogs. That would be the lightest, but most expensive, option for me.

My question is this. Is the NeoAir All Season pad warm by itself, with nothing under it, down to 20F. Does anyone have experience with it?

I've used the NeoAir original on top of a Z-rest pad (both shorties), with my pack under my lower legs, on a zero degree night and stayed warm. (It was only supposed to drop to 10.)

However, when the All-Season came out, I jumped on it. ("Hi, I'm Glenn, and I'm a gearaholic...") I got the 66", which is effectively a full-length pad for me, since I'm 5'10", and my head isn't on the pad (it goes on my pack, which doubles as my pillow.)

I've used it for two nights, both of which were 15 to 20 degree nights, in December; my buddy was using an identical pad on the same trip. Neither of us felt any cold seeping in. In fact, we felt heat radiating back up to us through the bottom of our sleeping bags. (We both noted that, when you first lay down, or when you shift your legs to a new position, the pad feels cold for about 20 seconds, until you've heated that part of the pad up. Then it's toasty warm.)

My buddy and I have both been very pleased with our All-Season pads, and feel the money was very well spent. We're going to use them again this weekend, when the lows are predicted to be around 20; I'll let you know if we have any change in our opinions.

Since I've had the original NeoAir comfortably down to the low 20s I've got to believe the All Season will go rather lower by itself. You could simply add a thin (1/8 inch) foam pad beneath the regular and do quite well, I'd think.

Cheers,

Now, now. No more jumping on the bed.

(Sorry, couldn't resist! )

Yeah, my bad.

I originally wrote, "...my buddy used the same pad..." but I caught that one and changed it to "...an identical pad..." to avoid getting caught up in the "two guys on one pad?" questions.

You guys are way too sharp!

Hey, we don't judge here.. if you can pull it off it's a weight saving technique

Only if the other guy carries the pad!

I just put these comments in another thread, but relevant here, so ...

IMO the advent of the Neoair XLite model makes the All Season model less interesting. In size regular (72" x 20" x 2.5") the XLite is 7 oz lighter (12 vs 19 oz), and has a listed R-value of 3.2, vs. 4.9 for the All Season.

If you want the beefier R-value, I would find it more flexible to buy one or more Gossamer Gear thinlight pads, in 1/4" or 1/8" (or one each, for max flexibility). In 1/8" thickness a thinlight pad is 2.2 oz. Admittedly, added bulk, but not too bad overall, and in warmer weather you can just leave it home.

Or, if you already have the All-Season, you could just buy an XLite for warm weather...

When I told my wife that "Brian says I need to buy another pad," she explained to me that your parents were never married.

My local outfitter, on the other hand, wants to buy you dinner.

The amount of insulation added by a 1/8" CCF pad is extremely small. Mark Verber in his encyclopedic analysis of sleep systems shows the R value of the Gossamer Gear 1/8" Thinlite at 0.4.
EDIT, later: I do use a 1/8" Thinlite, but primarily to protect my pad and keep it from slipping. I also fold the Thinlite in half to use as a sit pad in the daytime.

I just couldn't get comfortable on a NeoAir--partly the small horizontal tubes (which kept "bucking me off" every time I turned over) and partly because I never could reach the "sweet spot" between my hip bone's hitting the ground and having the mattress surface too hard. I'll stick with my custom made KookaBay 3.5" thick air pad, with R5 insulation, which weighs 13 oz. and cost $150, making it comparable in weight and price with the NeoAir but a lot more comfortable--for me, at least.

The NeoAir is definitely not for everyone, so don't let the light weight lure you into getting one without a thorough trial (the voice of experience here!). At least I got mine from REI (with one of their 20% off coupons), so I was able to return it after unsuccessfully trying for several months to get used to it. There are other options!

I agree with you, OM: the NeoAirs are not for everyone. (No different than any other piece of gear.) I've had very good luck with them, but I completely believe you when you say you couldn't get comfortable on them. (I've never been able to get comfortable - or stay warm - on the Big Anges Insulated Air Core pads, but have meant plenty of folks who really like them.)

I have a long-time hiking buddy who switched to the NeoAir at the same time I did. He felt they were comfortable, but has recently relegated it to the closet and gone back to using his Thermarest Prolite Plus. He feels its extra warmth, reliability, and simplicity in use more than makes up for the weight difference. (Blowing up the NeoAir really bugged him.)

For now, though, I really like mine.

I know that I will be cold using it alone if the air temperature is below 35F.
That is one of the problems when comparing opinions on R requirements for mats.
The R value required is related to ground not air temperature so the same person at 35F could be warm one night but cold the next using the same mat (all other things being equal)


You guys are way too sharp!
And that is why they puncture their mats...
Franco

That sounds about right; I've seen it listed at 0.45, but that's quibbling. I don't agree that this is extremely small, however. If you were just thinking in terms of r-value per unit ounce, the pad offers more than the neo-air itself does --- stands to reason, ccf is pretty good insulation.

More importantly for me is that I can apply it where I want to. I'm not into (nor capable of) the sort of detailed analysis that folks on BPL get into about this sort of thing, but from trying it both ways it certainly "feels" to me that putting a thin ccf pad on top of an inflatable helps significantly (and more than putting the same ccf pad below the inflatable).

I definitely wouldn't suggest that the neo-air is the be-all and end-all for all hikers, just that for folks already considering one, combining the lighter version with one or more thinlight pads might be a winning combination.
It's worked well for me, in any event, allowing me to use the same inflatable pad in a variety of conditions.

I still think that a piece of single bubble foil insulation works better under, or over, a sleeping pad like the neoair than a CCF pad. A piece big enough to cover the largest neoair would probably weigh around or under 4-5 oz.

Are their any discussions on that at BPL?

What about adding a simple space balnket? 2 bucks. I did this in my hammock last year under my pad and wow what a diff on a cold night! Dont do it on warmer nights you will sweat like crazy. I will never not take a space blanket. When the thermometor dips unexpected, you can add a least ten degree rating to your gear. Best thing is it cost pennies and about 2 ounces!

W/O getting all sciency I suspect that since the NeoAir already has an IR barrier inside so I'm skeptical adding yet another, without some sort of air gap, will gain any warmth. I think what you want is to slow conductive loss, e.g., foam of some sort.

Cheers,

(Groan!) Guess I had that one coming.

I disagree Rick, the radiant reflector in the Neoair is probably not as effective as the "foil". The bubbles provide an air gap, and it's tough enough that it can be used as a ground sheet under your pad. When it's over your pad the reflector is closer to your body, and your sleeping bag will be providing additional air space.

And I fully agree that adding a space blanket over your bag is a good idea too. Your bag is providing the airspace in that instance.

As I've said before, I use bubble foil for a sitting pad too. Based on my experience I don't believe a piece of CCF, no matter how thick it is, will keep you as warm, and it will weigh more per square foot and not pack as well.

What can I say? I haven't ever found reflective sheets to be of any benefit beyond stopping airflow, nor bubble pads. But they don't weigh much so there's no harm in experimenting.

IMHO you have to deal with conduction first, convection second (higher priority if using an air mattress or sleeping in a hammock) and radiation last. I don't believe Jardine and I agree on that last bit.

cheers,

Perhaps in this instance we do need to get a little 'sciency', as I think it's too easy otherwise to draw general conclusions from limited, specific circumstances. I.e., one person might use a space blanket in their sleep system on a particular night and conclude that it kept them significantly warmer --- and maybe they're right. Another might conclude that it did more in terms of adding noise at night and getting them wet by not allowing water vapor to pass --- and maybe they're right too in their particular situation. My own experience at trying a space blanket a few times in colder weather with my hammock was more towards the latter, FWIW.

Using a neo-air, my inclination is towards Rick's thought about the radiant reflector built in. Perhaps it's not as good at heat reflection as a space blanket, but the incremental gain of the space blanket might not be worth the hassle of adding it? Given that it only addresses one of four ways of heat loss (Conduction Convection Evaporation Radiation) and the suckers tear so easily (not a great approach for use night-after-night-after-night), I'm just not a fan except for emergency use.

Bubble foil: I have no experience. Indeed, weight and bulk per measured R-value gain could help put this in perspective, with the caveat that listed r-value for a specific construction installation might not translate to r-value as measured as part of a sleep system. I'd also be curious about durability, given the "bubble" part of it --- is this likely to slowly degrade as various bubbles pop? All materials degrade with use; ccf degrades quite nicely, slowly.

I suspect that with a lot of experimenting backpackers out there, if bubble foil was a great option for sleep systems we would have heard of it in this context a lot more often. Here's one short BPL thread on the topic, fwiw.

The big thing on radient bubble "stuff" - specifically the research I read in regards to housing (you'd be surprised how much a house "lives" and breaths like a human being) - is that you need a 1/4" of space to reflect into AND the reflective surface has to be very clean. So I can see the tent working and a good idea, but not as a sleeping pad.

More info than you ever wanted to know, but http://cchrc.org/docs/reports/TR_2011-01_Reflective_Insulation_in_Cold_Climates.pdf

A good idea of how it works,maybe, can be understood looking at the Neo Air All Seasons.

The R4.9 is obtained by trapping warm air inside those many chambers (apparently 100) using those reflective barriers.
When deflated the R value is about 1.5 about the same as a blue mat.
Franco

Well, I am no expert and I won't pretend to know all the science behind it, so I won't say anyone is wrong, but I will explain my thoughts so you all can review and critic my logic...

I looked into the "R" value of bubble foil yesterday and from what I could gather a single layer with one white side and one reflector side (like I use) has an R value of about 3. If you add dead air space the R value increases by a value of 1 for every inch of air space.

I'm guessing that the trapped air in the polyethylene layers traps heat to provide the first 3" of R value to bubble foil because just the reflector sheet (a space blanket) has no R value at all by itself. My "Baker's Tent" made from space blankets does trap the heat. That's easily proven. It's basically one big bubble made the same way as bubble foil.

Okay, so now we know that a space blanket will provide more R value as it's covering a bag with more loft. That's an important thing to understand in how it works.

But that's not the whole story as I figure it. I'd think that what we want for our purposes is a minimal amount of air between our skin and the reflector. What we want to do is retain our body heat in our body, not in a sleeping bag. That's the logic I'm working with.

With that in mind, it also makes sense to me that the more loft you have in your bag the less you'll feel the effects of a space blanket over it because that loft is absorbing the radiant heat you are emitting before it gets to the reflective layer.

If I am correct, then if you wore a thin layer of anything that has air space (fleece would work) with a space blanket over it, and then added R value (get inside your sleeping bag) you'd add the most warmth (to your body) with the least weight.

The issue there, we know, is condensation. That's a problem with the fabric, but as I've pointed out previously there are breathable reflective fabrics now. No one has tried them as far as I know. I think we have to test the potential for that.

Still, right now a space blanket laid loosely over your bag does breath quite a bit, and I've never experienced condensation doing that. I have experienced the increase in warmth, and very quickly too. This was with a 32º (optimistically rated) synthetic bag, that is not high end, in mid 20ºs nights.

What I will say for sure is that I know the stuff works (neoair is using it for that reason), we just haven't figured out how to make it work best for us yet. I'm playing with that a little and seeing some very good results.

And like you said, "there's no harm in experimenting"

The clean reflective surface is facing the air bubble, so it stays pretty clean. The reflective surface does deteriorate on the outside of bubble foil with use though. This is especially true with the reflective surface on SOL space blankets, it rubs right off, and they will be certainly be less effective as it does.

Heather, you should make one of those tents for grins (and you have so much spare time ). Seriously though, I think you'd have a blast playing with one up there with on your property.

We are kinda all thinking the same things. In my case the neoair is unessasary in a Hammock . I need warmth not comfort. Howvever it was mentioned i use a space blanket. This comes from Henneseys 4 season system . Look at the vidios on there site. Noisey, yes so my idea is to contact adhesive space blanket to top of underliner pad! Should calm the crunchy right down? Second there system puts actual hammock bottom between liner pad and space blanket. Has anyone tried this out? Bottom layer is breathable so does it block out the condensation issue? Third , another idea of mine is to use a thin Gossomer gear Evosote closed cell pad inside the hammock over it all. Closed cell doesnt absorbe moisture from below. When I get this all together and a final weight compared to my current thermarest ridgrest, I shall post it. The neo air scared me and so does straight bubble foil. They both look like condensation traps to me! I used a space blanket one night directly under my sleep pad inside Hammock. The moisture in the morning was bad! I am not trying to change the subject to Hammock systems but we seem to have related issues!
Hmm, Wonder if Thermarest Bonded a 1/8 inch or even 1/16 inch layer of evosote to top of there neoair? Wouldnt pack as tight , but would it be the holy grail of winter ground pads? I need to shut up and call the patent office! LOL, Happy Trails

I would try using 3M glue to laminate a SOL blanket to a fleece blanket and use that as an under quilt. The reflective surface should be on the bottom, facing the hammock. I would cut slits (or slots) in the reflective surface if moisture build-up was a problem.

Or, I would try a piece of the breathable reflective material I linked to in a previous post all by itself.

This stuff here

Just got back from an overnighter - temps got down into the 20-25 degree range. I used the 66" NeoAir All Season (third night of use) and stayed plenty warm - essentially the same results as the two previous nights.

Actually, I have been thinking about it. I have the time, I'm just in the middle of a very bad case of winter hibernation. Though so far I have two backpacking trips planned - one in March in Cali (3 nights) and one in early May nearby (another try at Chena Dome.)

So I'll attempt to start this project (I have parts for a camping stove, a wrap-around insulated skirt... well you get the idea.)

I used the regular neoair (L) with the 1/8" thinlight underneath in temps down to 17 degrees last year in PA. the ground was very cold, been low temps for weeks. I use the thinlight as a sit pad and to protect my neo air. I can say that when kneeling on the neo air, I could definately feel the cold, very cold, when on parts not over top the thinlight pad. I stayed warm all night using this combo and WM badger, just longjohns.

This year I've been in temps down to 11 degrees with the Xlite and 1/8" thinlight-same sleep system, and stayed very warm and comfortable. Though whatever tactile material is on the bottom of the Xlite grabbed and shredded my thinlight as I tossed in my sleep.

Bill I like that idea or I may bond sol to synthetic insulation like phat talked about. I havent had time to get to wallyworld yet. The slits to ley moisture out is a very good idea. I may face insulation with sol on one side and ripstop on the other?

Speaking from experience, the "reflective factor" is hugely overrated compared to the chill you'll get from the fact that underneath you won't breathe. I'd try it without the reflective blanket.

You could add a full length 1/2" generic blue closed cell foam pad to your regular NeoAir. I've done this down to 20 degrees. Below 20 degrees, I would go with a 3/4" closed cell foam like the thicker Ridgerest. These add-on pads are also useful for sitting on in camp around a fire or whatever without worrying about damage to your expensive NeoAir.

My experience has confirmed none of that, no "chill" no "condensation", no "moisture" issues at all, and as I've pointed out several times, there is a breathable reflective material available one might try if those are a problem for you.

Here's a real world test that's worth watching:

I suspect there's only a limited amount of IR radiation to "capture" and that moar reflective layers aren't additive, like R-values. If someone, for example, is already using a reflective NeoAir (not the Trekker) adding still more reflective layers isn't likely to do much.

That's my two pesos,

I'm sure you're right about adding more reflective layers, but I'm pretty sure that not all reflective layers are equally efficient. The one on a NeoAir is probably not near as efficient as those on emergency blankets, so an emergency blanket under a NeoAir may help keep you a bit warmer, but I'd suspect it wouldn't be much.

It also makes a difference on how close the reflective surface is to your body, so one placed on top of your NeoAir may also help keep you warmer. Since the NeoAir material does not breath, I see little downside in trying it on top of one if you're cold.

When reflective layers touch they become effectively worthless. A reflective layer is usually thin and metallic. That means they have high conductivity and very little heat capacity. They will quickly equilibriate with what ever they are touching. If you lay a Neoair on a reflective layer, the two will quickly become the same temperature. It won't matter what the reflective property of the layer it is sitting is since the radiation exchange is occurring inside the mat, thus only the reflective properties of the mat matter. Because of conduction the space blanket's radiative properties are moot. Now you proposed, a bubble mat with a reflective layer. The bubbles are designed to reduce conduction between the top and bottom. However you do indeed get a diminishing return on each additional thermal layer. I suspect Neo Air's already use multiple radiation layers inside the pad(at least the new ones), so you probably won't get much additional benefit regardless.

I can go into the equations if you are interested.

"I can go into the equations..."

If you do, I'll start quoting the Internal Revenue Code!

I think you're wrong about that.

What is relevant is how much radiant heat is passing through the neoair layer and if any of it can be reflected back inside the NeoAir by the bubblefoil layer.

The bubble foil reflects about 96% of radiant heat. I've looked at the reflective material on a NeoAir and I doubt it achieves that efficiency. It just not near as reflective. That's what I based my assumption on when I said placing bubble foil under a NeoAir might add a bit of warmth.

I think I also said it works better if you lay it on top of your pad.



Since mine is not a new model, that would seem to confirm my observations. The trick for them is getting the reflective layer about 1/8" under the top of the mattress with airspace in between, like bubble foil does. No easy trick, they can't trap the air, the pad won't pack down small if you do that.

--

It seems clear to me that how well these non-breathable reflective materials work is a very personal thing, might be somewhat regional and weather conditions based too.

Phat apparently gives off more moisture than I do, and because of that a SOL type layer does not work for him. There's nothing strange about that, we're all a bit different. But because they don't work for him is no reason I should not use them if they work for me.

As I've said, I think the material can be improved, or at least improvised better, for our needs. I even found and linked to a lightweight breathable reflective material that I think should be tested to see if it solves the kinds of problems Phat and others have experienced. I looks to me like it very well could, but I can't test it, I have not been able to duplicate those problems.

If that stuff works, just like it is, not yet optimized for our use, it could potentially lower your bags comfort rating by 10º, weigh less than 650 fill power down to do it, and cost less than $10.

Just because WM hasn't figured out how to incorporate it into their bags yet doesn't mean it can't or shouldn't be used. One reason they probably can't put a reflective layer inside a sleeping bag yet is because it loses its efficiency too fast, the shine wears off of it. But don't think they (and others) aren't still working on it. Whoever figures out how to use it first will have the lightest bags on the market.

I am not, but perhaps we are talking about two different things. My first comments were in regards to just a reflective layer.... like a space blanket. Your bubble layer will prevent conduction between the reflective layers. Your bubble layer could be quite effective with a lower R-value neo air, however putting a space blanket under it won't help much. You are in essence making it closer to how the newer higher R-value neo-air's (I suspect) are designed.

I agree adding a light breathable reflective shell material to a sleeping bag could greatly improve efficiency. Problems could involve having a loud crunchy sleeping bag with an uncomfortable fabric, but it would be interesting to see how it turns out. It sounds like you should get into the sleeping bag business.

No need to wait, you can have a bag with reflective layer today. (Scroll down to "radiant.") It'll cost ya.

Warmlite sleeping bag options

There were a few such options back in the '70s and '80s. The only one I had first-hand experience with was from Early Winters--considered an ultralight model back in the day. Did the reflective layer make a difference? Heck if I know (since you couldn't, uh, rip it out to test). It wasn't a luxurious bag, but back then 800+ci down and advanced synthetics didn't really exist, either.

Cascade Designs considers their pads to be part of their sleeping systems, so if they feel it's warranted they might market a quilt or overbag with an IR layer.

Cheers,

Their you go.

The only thing is, he says they put the reflective layer on top of the down. I believe that the reflective layer would work better if it were placed 1/8"-1/4" above the inner layer (closer to your body), and with the down on top of the reflective layer to add R value.

The best solution might be to add a very thin inflatable layer made with a reflective surface inside the top layer of the bag. A NeoAir that's 1/8' thick if you will. That obviously has the "spring a leak" draw back, but it might work incredibly good too and it would inflate with just a puff of air.


I'm just a futzer at heart. The design, testing, and manufacturing processes interest me, but the business side doesn't a bit.