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I would have guessed that it would condense at the point of warm/cold so the top layer of sleeping bag/blanket???? If you were covered by a waterproof layer it would condense under that.
(Like the walls /windows of the rig.)
Just below you would be warm and deeper into the mattress where it got cold would be on the other side of the vapor barrier.

AT , your hammock had you up in the air , the warm/cold interface was at that waterproof barrier and moisture above you probably evaporated.....

My mattress is enclosed by a waterproof cover to keep it from absorbing moisture from the wall/window it rests against , I never find dampness below me but I did notice one time when I covered my sleeping bags with some plastic to protect me from a small roof leak from my antenna crank and in the morning the underside of the plastic was quite wet. And the top of the outer bag was a little damp too.
\edit/ I remember also, back when I used an air mattress it was dry too.

I guess the OP could experiment to find out what happens.
 
I have only Reflectix that covers my windows in the van, a Mr. Buddy heater, a 12v blanket, a sleeping bag that is good to -20 degrees, 3 comforters, my pillows, and I have thermal wear if needed plus a couple of warm hats/gloves. Like someone else on here shared, I just turn my heater on and stay under the covers until the van warms up enough for me to get dressed. 

VanGrrl57 :)
 
Wanderer said:
I've been sleeping with my heater going all night long for the past 4 winters. 4K BTU with windows opened a bit.. Too many people have some vague horror stories where people have died from  mainly their own  stupidity in operating the heater.

The horror stories aren't at all vague.  They are in fact way too common. 
I remember a Grandfather taking his grandsons hunting in Pennsylvania a few years back, they stayed in his "cabin" with a propane heater running all night to chase the chill away..... none of them woke up the next morning. 

People being stupid? 
Well that's sadly getting frighteningly common!   

You my friend are way above average staying alive with a little buddy burning all night. 
I'm guessing no oets either? 
They can really screw up "safe placement" of flames. 

I would NEVER encourage anyone to ever sleep with an unvented combustion heater running! To do so is just inviting disaster, but I guess the "survival of the fittest" concept needs to come into play somehow? 

Dave
 
I am not a full timer, but I do go camping. What I do is I have 2 sleeping bags, (one will fit inside of the other), and a fleece liner. Between all of them and a warm hat, I sleep well. Get the kind of hat that folds down over your ears and snaps together under your chin. you can also get comforters from second hand stores if the bags are not enough for you.
If reflectix gets you warm enough to sweat, maybe just use less of it, (like under your legs). You might try hanging the reflectix over your bed too, like a little pup tent. Just because it works well doesn't mean don't use it.
 
AlmostThere, That seems rather peculiar. I've had a 2'x5' piece of Reflectix in my reading chair for three years. I sit there for hours in either my regular clothes, or my pajamas. Nothing has ever gotten wet or even dampish.

I'll have to try it in my bed and see what happens, for future reference.
 
Benjamin Dejo said:
Wouldn't your lungs freeze at -60F?

Lungs still work  :cool:  Little kids in Siberia play outside in those temps.  You learn fast to breathe through your nose.  I created a microclimate by using a thin poly blanket to cover my head.  Blanket was frozen stiff in the morning.

Almost There said:
Yes, I've woken up with wet bedding beneath me from condensation. Fortunately for me, it was the underquilt on my hammock that contained all the moisture. Also fortunately it was the last night of a camping trip so I didn't have to try to get the bedding dry until I got home. There was enough moisture in the underquilt protector that I had to use a towel to mop up.

I've slept over a blue closed cell foam mattress (doesn't absorb water, doesn't breathe) for years in heat and cold, don't get condensation under me unless I am sweating (hot weather or too much cover).  Same with a Therm-a-Rest.  Currently use a down filled air mattress; no sweat under me.  I do move around at night, so maybe that is the reason but none of the other guys I have climbed with have ever reported sweat under them.  I have read reports of those sleeping in a camper over an open cell foam mattress of condensation on the underside of the mattress in cold weather (this after multiple days of camping).  Those using Therm-a-Rest mattresses haven't reported damp bedding.  Not sure what why the difference.  

rvpopeye said:
I would have guessed that it would condense at the point of warm/cold so the top layer of sleeping bag/blanket???? If you were covered by a waterproof layer it would condense under that.
 (Like the walls  /windows of the rig.)
Just below you would be warm and deeper into the mattress where it got cold would be on the other side of the vapor barrier.
. . .

My mattress is enclosed by a waterproof cover to keep it from absorbing moisture from the wall/window it rests against , I never find dampness below me but I did notice one time when I covered my sleeping bags with some plastic to protect me from a small roof leak from my antenna crank and in the morning the underside of the plastic was quite wet. And the top of the outer bag was a little damp too.
\edit/ I remember also, back when I used an air mattress it was dry too.

You are correct.  Body heat will drive your insensible persperation through your covers to condense somewhere outside of the covers.  In below freezing temps my inside tent walls were covered with frost from perspiration and breathing vapor.  When i used a Goretex bivy sack the inside of the bivy sack and the top of my sleeping bag was wet.   I learned on my first trip to Alaska that down was not a good insulator for that environment.

 -- Spiff
 
Well, my test camp out on the new bed resulted in mixed results. I read lots of horror stories about CO deaths, so I decided NOT to run my Mr. Heater while sleeping. I want to say I've owned my Buddy for a couple for years and have slept with it on all night in a Coleman tent & a pop up camper. Neither of those are even remotely air tight, so I really wasn't worried and woke up with no after effects. I have a battery powered CO Monitor.

I ran it after supper & while I watched a movie, it got shut off & I rolled up my front window before I crawled under the covers. I woke up about 4 hours later for the middle of the night whizz, and when I got back in the van I decided to fire it back up (opened window again) and warm things up a bit before getting about 3 more hours of sleep. Naturally, I fell asleep while it was running, but I only slept a couple of hours before deciding I'd had got all the sleep the night was going to offer.
My conclusions are - I'm fairly happy with my bed set up. My mattress is about 11" thick and I had plenty of blankets, so I wasn't cold until I crawled out of them. I could have made it all night without restarting the heater, although is was quite chilly here that night, around 27° at the coldest.
As with everything, use common sense. Be aware of combustibles and make sure you have fresh air coming in if your running any kind of heater that uses fire. Always include a CO monitor!!
 
DannyB1954 said:
I am not a full timer, but I do go camping. What I do is I have 2 sleeping bags, (one will fit inside of the other), and a fleece liner. Between all of them and a warm hat, I sleep well. Get the kind of hat that folds down over your ears and snaps together under your chin. you can also get comforters from second hand stores if the bags are not enough for you.
If reflectix gets you warm enough to sweat, maybe just use less of it, (like under your legs). You might try hanging the reflectix over your bed too, like a little pup tent. Just because it works well doesn't mean don't use it.

Would a full size NASA style heat reflecting space blanket overhead work just as well as Reflectix? I've got several of the heavy gauge space blankets with grommet holes in the corners. I used one in the bottom of my tent under my megamat. My outdoors wilderness guide said I'd get better heat insulation if I could figure out how to hang it overhead in the shape of the tent. Heat rising, reflected back onto my body. Seems like same inside vehicle. Would condensation be a problem with no heater on in the minivan???
 
Kathleen said:
My outdoors wilderness guide said I'd get better heat insulation if I could figure out how to hang it overhead in the shape of the tent. Heat rising, reflected back onto my body. Seems like same inside vehicle. Would condensation be a problem with no heater on in the minivan???

The shinny part of the reflectix or space blanket works with radiant heat, ( There are 3 forms of heat flow, Radiant, Convection and conduction). That being said, the plastic part of both refletix and space blanket would slow the convection heat from your body from rising as quickly, so it should help keep the space above you a little warmer. Many homeless use cardboard in this manor.
 
Spaceman Spiff said:
Lungs still work  :cool:  Little kids in Siberia play outside in those temps.  You learn fast to breathe through your nose.  I created a microclimate by using a thin poly blanket to cover my head.  Blanket was frozen stiff in the morning.


I've slept over a blue closed cell foam mattress (doesn't absorb water, doesn't breathe) for years in heat and cold, don't get condensation under me unless I am sweating (hot weather or too much cover).  Same with a Therm-a-Rest.  Currently use a down filled air mattress; no sweat under me.  I do move around at night, so maybe that is the reason but none of the other guys I have climbed with have ever reported sweat under them.  I have read reports of those sleeping in a camper over an open cell foam mattress of condensation on the underside of the mattress in cold weather (this after multiple days of camping).  Those using Therm-a-Rest mattresses haven't reported damp bedding.  Not sure what why the difference.  


You are correct.  Body heat will drive your insensible persperation through your covers to condense somewhere outside of the covers.  In below freezing temps my inside tent walls were covered with frost from perspiration and breathing vapor.  When i used a Goretex bivy sack the inside of the bivy sack and the top of my sleeping bag was wet.   I learned on my first trip to Alaska that down was not a good insulator for that environment.

 -- Spiff
Hmmm, Spiff, you had your down bag inside your goretex bivy sack and your sleeping bag got wet??? Darn, I was thinking I would use the same combo in my van when it gets cold.
 
Anything that blocks the evaporation of the water that we all give off from our bodies will condense and wet the area, doesn't matter if it's down or not. I ended up with a wet underquilt one night because I tried using a silnylon protector to help block airflow under my hammock. Underquilt is synthetic, silnylon doesn't breathe, just like goretex doesn't.

You're better off layering your sleeping gear - microfleece thermals, then a fleece sleeping bag liner, the sleeping bag, throw a wool blanket over top of that if you're still cold but you shouldn't be - always wear a hat of some kind - I lke my fleece hoodie because it keeps my neck warm too, and warm socks.
 
Almost There said:
Anything that blocks the evaporation of the water that we all give off from our bodies will condense and wet the area, doesn't matter if it's down or not. I ended up with a wet underquilt one night because I tried using a silnylon protector to help block airflow under my hammock. Underquilt is synthetic, silnylon doesn't breathe, just like goretex doesn't.

You're better off layering your sleeping gear - microfleece thermals, then a fleece sleeping bag liner, the sleeping bag, throw a wool blanket over top of that if you're still cold but you shouldn't be - always wear a hat of some kind - I lke my fleece hoodie because it keeps my neck warm too, and warm socks.

Thx for the info, Almost There. I own a great siltarp. It works outdoors over the goretex bivy bag, a lightweight set up, with the bivy on top of a tent footprint. It's a light weight sleep set up if I want to camp in a beautiful spot away from my vehicle. I don't have screens on my windows. May try the insect bivy inside the van if the bugs get bad.

I will wear a wool hat and hoodie to bed. Merino wool layers, head to feet when temps drop. You can wash merino in warm water and it dries quick in the shade. Anti microbial, no odor, wear it for days, even weeks, does not absorb human scent. Can be found at good thrift shops. Costco makes merino wool sleep pants.

I have 3 sleep bags for different temps and wool blankets. It will be the great experiment when I get out on the road.
 
It isn't too cold unless the five gallon water jug freezes solid, then it is time to head to a warmer elevation/latitude.

Having enough sleeping bags/blankets isn't too much of a problem.  The biggest issue is getting up in the morning and any night time forays that are required.  Sleep fully dressed, with socks.

In colder weather I like to take a hike in the morning to warm up, by late morning it will hopefully be in the upper 40's/50's.  This is quite doable in sunnier climes, and with less wind.
 
Almost There said:
Anything that blocks the evaporation of the water that we all give off from our bodies will condense and wet the area, doesn't matter if it's down or not. I ended up with a wet underquilt one night because I tried using a silnylon protector to help block airflow under my hammock. Underquilt is synthetic, silnylon doesn't breathe, just like goretex doesn't.

You're better off layering your sleeping gear - microfleece thermals, then a fleece sleeping bag liner, the sleeping bag, throw a wool blanket over top of that if you're still cold but you shouldn't be - always wear a hat of some kind - I lke my fleece hoodie because it keeps my neck warm too, and warm socks.

If you read the accounts written by early polar explorers, they had the same problem, but worse—the moisture buildup inside their down sleeping bag during the night would freeze during the day in the intense cold. (They write of having to break open their sleeping bags every night so they could get inside.) When this frozen moisture then thawed from their body heat during the night, it made their bedding wet, ruined its insulation, and sapped precious heat from them. Without periodic fires to dry out their bedrolls, the cold night air would have eventually killed them.

I keep three sleeping bags in the van--a lightweight mild-weather bag (which also doubles as a  liner for the heavier bags), a mid-weather rated to 50, and a cold-weather mummy bag rated to 30. If necessary, I layer one inside the other. 

If it's REALLY cold, a trick I used to use while backpacking in PA was to use two bags and put a large plastic trashbag between them, to trap heat. Alas, it also traps moisture, so your inner bag will get wet. I dried it out during the day.

But mostly I deal with cold weather by moving further south.  ;)
 
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