10 below, on a pad, in a bridge

[509-T203-KG]

Backyard test on 03/03/2019:

DSCF4495.jpg

I was enjoying a relaxing Sunday evening at home before starting another work week when my phone notified me of a "Wind Chill Advisory". I decided this might be my last chance this season to test against temps this low.

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Projected Forecast:

• Low temperature: -2°F, wind chill -10 to -20.
• Wind: Only 5-10 mph, which is apparently enough to warrant a wind chill advisory.
  Wind Chill 1.PNGWind Chill 2.PNG

Actual Conditions:

• Low temperature: -10°F
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• Wind: Who knows... there was some.

Gear:

• Hammock: REI Quarter Dome Air.
• Tarp: I was too tired and lazy to pitch one, despite the wind chill advisory. I convinced myself it was fine since I could easily bail. Plus, I could test a theory about my hammock and pad acting as a wind block. Also, it didn't actually seem all that windy outside.
• Under Insulation: Therm-a-Rest NeoAir XTherm MAX Large, inflated to max capacity. R-Value = 5.7, temperature rating: unknown... somewhere between -10 and -40°F (more on this below).
• Top insulation: Sierra Designs Mobile Mummy 40°F, two unmodified Costco down throw blankets laid over top, and my down parka over my feet.
• Pillow: Sea to Summit Aeros Premium Regular.
• Hammock setup: a record low number of steps for me (likely due to the cold, haha):
  - Attach strap 1 to tree 1 - attach strap 2 to tree 2 - attach hammock to strap 1 via Beckett Hitch - attach hammock to strap 2 via Beckett Hitch - tighten the ridge line a bit - sit test - SEND IT!!! Aside from the ridge line, I didn't make a single adjustment. My lazy and hurried setup had too much sag and wasn't centered between the trees very well, so the lay was not as flat as my previous two hangs.

Clothing:

• Feet - heavyweight wool socks.
• Lower body - basic long johns and sweat pants.
• Upper body - long john top, 1/4 zip micro fleece pullover, lightweight Eddie Bauer down hoody from Costco.
• Head - balaclava, wool/synthetic blend beanie.
• Hands - light/mid-weight fleece gloves taken on and off throughout the night.

Personal Stats:

• Height: 5'9"
• Weight: OVER (185 lbs)
• Flip-flopping side sleeper

Sleep Summary:

• After a brief struggle to get properly situated and comfortable (always more difficult in the cold), I fell asleep quickly around midnight and slept hard until I woke up needing to pee. I decided to see if I could hold it until morning and fell asleep again for another 30 minutes. This time when I awoke, I felt a little chilly. I checked my watch... 2:30 a.m., ugh, gonna have to get up...
• Getting up to pee was pretty miserable, haha. For some unknown reason, I decided to exit my mobile mummy instead of just sticking my arms and feet out and wearing it. It was about -6°F, and I was feeling every bit of it. While it didn't seem "Wind Chill Advisory" windy, I certainly noticed a breeze while I was out, and there was an urgency to get back in the hammock. Getting re-situated was painful, my body and hands were definitely feeling the sharp cold.
• At this point, I was concerned about regaining heat, especially on the underside. On a previous test, I struggled to get warm again after getting up. I've wondered if when you get up, the pad loses its stored heat by conduction, and needs body heat that I no longer have to get warm again...
• I considered bailing at this point, but stuck it out, and after 5-10 minutes I started to get warm again and managed to sleep comfortably until my alarm went off at 6:45 a.m., only waking occasionally for adjustments.
• Wind: every once in a while I would feel a gust on my face and need to adjust to cover more, but that was it. I never felt it under me, and surprisingly didn't notice it affecting me from above either.
• I can easily and comfortably side sleep in the fetal position all night with this setup. Probably the best sleeping position to conserve heat.
• Other than directly before, during, and after having to get up to pee, no part of me was cold. I wouldn't say I was "toasty", just "not cold".
• The only observable condensation I could find was within about a 1-foot radius from my mouth. Not enough to bother me. I did not weigh the gear or measure loft before and after to test for condensation inside.

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Thoughts and Conclusions:

• I need a way to measure wind... I really have no idea how windy it was or what the wind chill was.
• I do know that there was some wind and, aside from the exposed part of my face, I didn't notice it. I still feel like the pad and thicker material hammock side walls act as somewhat of a wind block.
• While getting up to pee was unpleasant, it was the right decision. I would've continued to not be able to sleep and be cold (been there before).
• The more I use this pillow, the more I think it might be nice to have the additional side-to-side width of the larger size for car/backyard camping.
• When I came inside in the morning my wife said "So you made it, huh... I guess that means you don't need to buy any new gear!" DOH! But I suppose she's right... while it'd be nice to have a lower rated quilt or bag so I don't have to layer as much, I can get by with what I have down to -10°F (or however cold it was with wind chill). Like I'm not going to buy new gear though... ha!
• I still haven't found the lower limit for the pad. According to the chart I've seen floated around on here, at an R-Value of 5.7, I'm flirting with it. Then there's the chart printed right on the box that seems to say I should be good to -40°F? Not sure I'll ever get to test that. So, aside from developing some sort of DIY method to keep my pad in place better, I don't foresee ever needing to upgrade my under-insulation.
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If you're interested, here's a link to another thread containing 4 additional reports using some, or all, of the same gear. Happy hanging! https://www.hammockforums.net/forum/...Hang?p=1947322

- KG

[psyculman]

Thanks for posting this. Some usable information there for me.

[Crazytown3]

Looks pretty comfy. Those Costco down throws are a nice supplement to existing gear, even when they are unmodified. I use them myself to supplement both my top and bottom quilts.

I love backyard test hangs like you did. There is minimal risk, and huge rewards in terms of testing gear.

[sidneyhornblower]

I'm extremely impressed with that performance. Reading the list, I would have said there's no way you had enough insulation but you proved me wrong. Maybe this is a good argument for the effectiveness of stacking layers of various ratings. It's also a good advertisement for that pad. There's no way I would have had the guts to try those temperatures without a lot more insulation under and over me, including an underquilt protector for wind breaking.

Thanks for posting such a comprehensive and data rich report.

[NJHeart2Heart]

I'm jealous that you have the trees to hang in your backyard!

[BillyBob58]

Thank you, thank you, thank you for extensive testing of this pad in a bridge hammock! Long ago, Ducttape did minus 22F with CCF pads and was fine. But, your recents tests are the first extensive testing pushing the limits of these NeoAir winter pads- in a hammock- I have read. The incredible part- compared to even zero rated UQs- is that you were able to get by even without a tarp blocking wind chill! So either wind chill is simply not a significant factor with these pads, or you would have been fine even to a significantly lower temp using a large tarp and/or an UQP under your pad. Plus, you had one other huge advantage going for you, especially in a back country, remote situation. Had it become too cold for sleep, you could always lower the hammock to where it was just barely touching the ground or snow. Either of which are most likely considerably warmer than the air blowing under a hammock. After doing that, you would probably be good for another 20-30 degrees. All of this with- if using the long wide- a pad weighing only 23 oz, less than many zero F UQs which would have suffered from the wind. And, not much different in volume either. Very impressive!

I have been really leaning towards switching to pads in either my bridge or 90* hammocks. Your testing has encouraged me along those lines. Considering that I can either be just as comfy, or or pretty close to as comfy, using a pad in these types of hammocks as I can with an UQ. The only thing that makes me hesitate is a slight worry about the ability to patch an inflatable pad - or worse what kind of loss of warmth a blown baffle might cause. In those areas(durability, simply nothing to go wrong) is where the total bomb proof CCF pads shine. But they take up so much more room, and are not as comfy if forced to ground, or if on the ground by choice when sleeping above timberline, or shelters.

BTW, speaking of flat inflatable pads: the other day I was experimenting with my NeoAir All Season in a WB bridge with pad pocket. This pad with it's 4.9 R value is not as warm as your 5.7 R pad. It was only a moderately cool day. But I started letting air out a little at a time to check differences in comfort and warmth. It wasn't very cold, probably not much colder than the minimum required to feel cold in a hammock. There was, however, a little wind. Any way, I wasn't feeling much difference all the way from fully inflated to completely deflated. Then I removed the fully deflated pad from the pad pocket and got back in. Bam! Easily noticed an uncomfortably cool back, especially when the wind would hit me. It would have definitely been too cold to sleep all night, but even with a fully deflated/valve wide open, there was a noticeable improvement in warmth, to at least adequate at these not really cold temps, plus wind chill. I'm sure it would not have been adequate in the 30s or 40s, but it still added a noticeable amount of warmth even without inflation.

[509-T203-KG]

Thanks for posting this. Some usable information there for me.

Nice! Glad you found it useful.

Looks pretty comfy. Those Costco down throws are a nice supplement to existing gear, even when they are unmodified. I use them myself to supplement both my top and bottom quilts.

I love backyard test hangs like you did. There is minimal risk, and huge rewards in terms of testing gear.

Yep, two CDT's gotta be about the best $31.98 I've ever spent. Even though it takes time to write these reports, it's nice to have documentation of the results for future reference. Plus, hopefully others can benefit from the info.

I'm extremely impressed with that performance. Reading the list, I would have said there's no way you had enough insulation but you proved me wrong. Maybe this is a good argument for the effectiveness of stacking layers of various ratings. It's also a good advertisement for that pad. There's no way I would have had the guts to try those temperatures without a lot more insulation under and over me, including an underquilt protector for wind breaking.

Thanks for posting such a comprehensive and data rich report.

I was also surprised by the performance (I figured I'd have to bail). Stacking insulation seems to be working well... perhaps the additional layers also help with cutting wind? And yes, I couldn't be more pleased with the performance of the pad. It's certainly doing its job... a case of "you get what you pay for". I'm also starting to put more weight into the fact that I'm able to sleep on my side, curled up in the fetal position. That has to make a fairly substantial difference in conserving body heat.

I'm jealous that you have the trees to hang in your backyard!

I know... I take it for granted, and I totally shouldn't. I'm very blessed!

[509-T203-KG]

The incredible part- compared to even zero rated UQs- is that you were able to get by even without a tarp blocking wind chill! So either wind chill is simply not a significant factor with these pads, or you would have been fine even to a significantly lower temp using a large tarp and/or an UQP under your pad.

My experience tells me that the wind just doesn't seem to affect it. The bottom of the pad is made from 70D nylon, per Therm-a-Rest.

Plus, you had one other huge advantage going for you, especially in a back country, remote situation. Had it become too cold for sleep, you could always lower the hammock to where it was just barely touching the ground or snow. Either of which are most likely considerably warmer than the air blowing under a hammock. After doing that, you would probably be good for another 20-30 degrees.

Are you referring to the whole "a pad is warmer on the ground than in the air" concept? While I've heard this here on the forum, I've never seen any actual documentation or testing to prove it. Is it the air moving under it that makes a difference? Or not being on a solid surface doesn't reflect heat back as well? Something else? I've only tested the pad in a hammock, and have gotten down to -10, so who knows.

The only thing that makes me hesitate is a slight worry about the ability to patch an inflatable pad - or worse what kind of loss of warmth a blown baffle might cause. In those areas (durability, simply nothing to go wrong) is where the total bomb proof CCF pads shine. But they take up so much more room, and are not as comfy if forced to ground, or if on the ground by choice when sleeping above timberline, or shelters.

Our Boy Scout Troop did a week-long backpack trip last summer and several others swore by the CCF pad for the reason of not having to worry about punctures. We did have one puncture on the trip and he was able to repair it on the first try. As far as the blown baffle, I think the thing you'd have to worry about is whether you could even sleep on it comfortably. It seems like plenty of people use inflatable pads for months-long through and section hikes though.
Blown baffle.jpg

BTW, speaking of flat inflatable pads: the other day I was experimenting with my NeoAir All Season in a WB bridge with pad pocket. This pad with it's 4.9 R value is not as warm as your 5.7 R pad. It was only a moderately cool day. But I started letting air out a little at a time to check differences in comfort and warmth. It wasn't very cold, probably not much colder than the minimum required to feel cold in a hammock. There was, however, a little wind. Any way, I wasn't feeling much difference all the way from fully inflated to completely deflated. Then I removed the fully deflated pad from the pad pocket and got back in. Bam! Easily noticed an uncomfortably cool back, especially when the wind would hit me. It would have definitely been too cold to sleep all night, but even with a fully deflated/valve wide open, there was a noticeable improvement in warmth, to at least adequate at these not really cold temps, plus wind chill. I'm sure it would not have been adequate in the 30s or 40s, but it still added a noticeable amount of warmth even without inflation.

Interesting. That's another aspect I haven't really tested. For all of this season's winter hangs, I have had the pad inflated to maximum capacity. When I first got the pad, I decided that I preferred it only partially inflated for comfort and stability. However, on the 4th night of our backpack trip, temps dropped below freezing (not sure how cold, but enough to freeze water bottles), and I was cold. The next night we had the same conditions, but I fully inflated the pad and I was warm. I've been fully inflating it ever since, and have learned to sleep comfortably on it and maintain enough stability.

[BillyBob58]

.............Are you referring to the whole "a pad is warmer on the ground than in the air" concept? While I've heard this here on the forum, I've never seen any actual documentation or testing to prove it. Is it the air moving under it that makes a difference? Or not being on a solid surface doesn't reflect heat back as well? Something else? I've only tested the pad in a hammock, and have gotten down to -10, so who knows.

Yes, that is what I am referring to. I have also not seen any documentation on this. And you getting to -10F with a 5.7 R value certainly seems to throw the whole concept into question. ( that really is a bit more than my expectations by a good 10F or more).

An 8 R value Exped Downmat(DM) 9 is rated to minus 38F on the ground. It has been assumed by many of us(and reported by some based on their experience) that pads are warmer on the ground than in a hammock. I don't know the rating for your NeoAir with 5.7R, butI calculate that, using the same rating per R value obtained from the DM9, it would be rated to about minus 7F on the ground. But you have already gone a bit below that in a hammock at 10F, plus some wind chill, and still warm. So, unless there is something very atypical about you, have we been under rating pads in hammocks?

I have a PDF file from Youngblood, a guy that used to post here and who invented the Speer Snugfit and the Speer Segmented Pad Extender(SPE). It was titled "Some Observed Temperature Ratings for Combined Inflatable Pads and Closed Cell Foam Pads as Used in a Speer SPE". A Thermarest self inflating standard 1.75" thick had an R of 5.8 and an observed temp of 12F. Though I suppose this was not a known max, but rather what it said: an observed temp. There was also a 6.1 R Luxury Camp with an observed 9F. Still, it is quite likely thes could go even lower. But can they go a low as on the ground? I am starting to wonder.

But it surely does make sense to me that a pad can keep us warm at a lower air temp if used on the ground. The ground can be 5 to 12+ degrees F warmer than the air, and on the ground wind under the hammock is blocked(though wind is apparently not much of a factor with these pads, but it would make a huge dif to someone unable to keep warm in an UQ due to inability to totally block the wind). But wind or no wind, the ground is often warmer. I don't know about snow temps, however, but I do know that snow is a great insulator.

Our Boy Scout Troop did a week-long backpack trip last summer and several others swore by the CCF pad for the reason of not having to worry about punctures. We did have one puncture on the trip and he was able to repair it on the first try. As far as the blown baffle, I think the thing you'd have to worry about is whether you could even sleep on it comfortably. It seems like plenty of people use inflatable pads for months-long through and section hikes though.

Blown baffle.jpg

Wow, what a picture! That sure looks like it would be a trip ender. The pad that you were able to latch: was it a NeoAir?

Interesting. That's another aspect I haven't really tested. For all of this season's winter hangs, I have had the pad inflated to maximum capacity. When I first got the pad, I decided that I preferred it only partially inflated for comfort and stability. However, on the 4th night of our backpack trip, temps dropped below freezing (not sure how cold, but enough to freeze water bottles), and I was cold. The next night we had the same conditions, but I fully inflated the pad and I was warm. I've been fully inflating it ever since, and have learned to sleep comfortably on it and maintain enough stability.

OK, thanks. Interesting that you were cold near freezing with a partially deflated pad, compared to being adequately warm at minus 10F with a fully inflated.

[BillyBob58]

Backyard test on 03/03/2019:



I was enjoying a relaxing Sunday evening at home before starting another work week when my phone notified me of a "Wind Chill Advisory". I decided this might be my last chance this season to test against temps this low.



Projected Forecast:
• Low temperature: -2°F, wind chill -10 to -20.
• Wind: Only 5-10 mph, which is apparently enough to warrant a wind chill advisory.


Actual Conditions:
• Low temperature: -10°F 

• Wind: Who knows... there was some. ……………………………………………………………………



Sleep Summary:After a brief struggle to get properly situated and comfortable (always more difficult in the cold), I fell asleep quickly around midnight and slept hard until I woke up needing to pee. ……………………………………………
• Other than directly before, during, and after having to get up to pee, no part of me was cold. I wouldn't say I was "toasty", just "not cold".
• The only observable condensation I could find was within about a 1-foot radius from my mouth. Not enough to bother me. I did not weigh the gear or measure loft before and after to test for condensation inside.



Thoughts and Conclusions: ………………………………………………………………………………
• I still haven't found the lower limit for the pad. According to the chart I've seen floated around on here, at an R-Value of 5.7, I'm flirting with it. Then there's the chart printed right on the box that seems to say I should be good to -40°F? Not sure I'll ever get to test that. So, aside from developing some sort of DIY method to keep my pad in place better, I don't foresee ever needing to upgrade my under-insulation.
- KG

(In response to my comment that, since he was using this winter pad, KG also had the advantage that if it was just not warm enough, he could just go to ground)

……………………
Are you referring to the whole "a pad is warmer on the ground than in the air" concept? While I've heard this here on the forum, I've never seen any actual documentation or testing to prove it. Is it the air moving under it that makes a difference? Or not being on a solid surface doesn't reflect heat back as well? Something else? I've only tested the pad in a hammock, and have gotten down to -10, so who knows…………………………………………………………….
.

(Me confirming that, yes, I was “referring to the whole "a pad is warmer on the ground than in the air" concept?”)

Yes, that is what I am referring to. I have also not seen any documentation on this. And you getting to -10F with a 5.7 R value certainly seems to throw the whole concept into question. ( that really is a bit more than my expectations by a good 10F or more).

Having just gone back through this thread, I realized I had missed something, and maybe KG had also. On the subject of whether a pad is supposed to be warmer on the ground than in the air, thus giving him the advantage if he finds himself cold at minus 10F. The advantage of being able to just go to ground for survival. He said he had never seen any documentation for that, and I couldn’t say that I had either. But I missed what he had said in his report, that the pad had a rating right on the box of minus 40F.

Since most backpackers and customers of Thermarest have always been ground sleepers, it is virtually certain that this rating is based on ground use. Until I am told otherwise, I will assume this rating is not for hammock use. Now KG has made it to minus 10F(plus some wind chill) in a hammock(no tarp) with this pad rated to minus 40F on the ground. We do not know if he could actually make it any lower and still be warm enough, and I found this to be amazing enough for 20 oz of pad with about the same volume as a winter down UQ. But what we can probably count on is that if he had found himself cold at that minus 10F, or minus 15F, according to the manufacturer’s rating on the box, he would probably be just fine on the ground, to even significantly colder temps.

The only question left(for me) is: could he make it to minus 40F, in a hammock, with just this pad under him? I find that to be highly unlikely, but I also do not really know. I have never seen it put to the test. Then again, as KG said, he has not yet reached the lower limit of this pad for himself, since he was still warm enough at minus 10F plus a bit of wind chill.