View Full Version : Cold Spots - Sleeping
Wise Old Owl
03-11-2008, 02:32
Just purchased an “ultralight” sleeping bag and tested in the back yard last night. This raised some interesting questions. Being a fat 46 year old guy, 215 pounds, I use a Big Agnes blow up pad because I am a mostly a side sleeper. The new REI Kilo Flash 40 Degree bag was just purchased. Last night was 44 degrees here in PA and here is the question.
I lost more body warmth through the BA pad (as expected) Even though I was using more air than a Thermarest that I just sold off 2nd hand. I put more air into it to ensure I was off the ground, to no avail. I found cold spots in the hips, feet, between the shoulder blades, and lower back. Everything else was TOASTY! I am not a cold sleeper…
What can be added to decrease the heat lost to the ground?
With this knowledge why would anyone buy a Big Agnes Sleep Bag?
Would the Primaloft version of the BA pad make that much of a difference?
What would you do differently?
Appalachian Tater
03-11-2008, 02:38
How do you know it was the pad and not the bag that caused the cold spots?
Wise Old Owl
03-11-2008, 03:01
The cold spots were always down not up.
freefall
03-11-2008, 04:32
Big Agnes actually has a decent reputation of matching their bags to conditions. Take a look at their customer reviews any where you can find them. I am bigger than you, presumably ( 5'10", 250 lbs) and I am comfortable in my hammock at 20* with a Kelty 20* bag and a Thermorest 3/4 length.
Honestly I am looking at a down 15* bag from REI. It is lighter than my bag and should carry me through many cases. (like this)
Salud!
fiddlehead
03-11-2008, 05:47
YOu can try putting raingear, any extra clothes, empty pack, anything, underneath the sleeping pad. It should help somewhat.
I wouldn't want to use a 40 deg bag. But then, i'm a skinny guy that does sleep cold.
I'd try it again with different amounts of air. (a great insulator in itself)
But wouldn't go out without my 1#12oz 20 deg Feathered Friends Hummingbird or something warmer, even in the summer. (you may not fit in one, they are quite small )
Also, keep in mind the ground is still colder this time of year and I don't know, is it still frozen? Air temp does not mean ground temp.
Survivor Dave
03-11-2008, 06:04
WOO,
When I first started planning for a Thru a couple of years ago, I went through the BA Lost Ranger, Lost Dog, Pomer Hoit..blah..blah etc.
I couldn't see spending a lot of mony for half a sleeping bag basically. YOU HAVE TO USE THEIR PAD! Boo! No one I know makes a 78" inch pad other than them for the long bags.
It is a good concept, but found the more you inflate the pad, the less room I had. I am a side sleeper and the whole shootin' match would roll with me. I also had a few cold spots where the pad came together with the bag.
So, I ditched the BA system and went to a Mont-Bell with a Prolite 4 pad. Yes, it's not as comfy as the inflatable, yes the prolite 4 weighs about the same, but after a few nights out on the Trail, hiking several miles, I had no problem getting to sleep. The Mont-Bell is awesome. It stretches with you.
SD
Just purchased an “ultralight” sleeping bag and tested in the back yard last night. This raised some interesting questions. Being a fat 46 year old guy, 215 pounds, I use a Big Agnes blow up pad because I am a mostly a side sleeper. The new REI Kilo Flash 40 Degree bag was just purchased. Last night was 44 degrees here in PA and here is the question.
I lost more body warmth through the BA pad (as expected) Even though I was using more air than a Thermarest that I just sold off 2nd hand. I put more air into it to ensure I was off the ground, to no avail. I found cold spots in the hips, feet, between the shoulder blades, and lower back. Everything else was TOASTY! I am not a cold sleeper…
What can be added to decrease the heat lost to the ground?
With this knowledge why would anyone buy a Big Agnes Sleep Bag?
Would the Primaloft version of the BA pad make that much of a difference?
What would you do differently?
Most air mattresses require a thin closed cell foam pad underneath and/or insulation in them to insulate from the cold ground. Air is a great conductor and while providing a great cushy ride, does not insulate as well as closed cell foam. Using an insulated version of an air mattress like you mentioned would also work, though cost more and weigh more overall. The Gossamer Gear 1/8" or 1/4" Thinlight pads are great closed cell insulation options that can be combined with any air mattress. Hope that helps!
Sounds like you are using the BA AirCore. This is basically just an air mattress and doesn't provide much insulation. The insulated AirCore provides a little, but not much. The BA Hinman is a self inflating (similar to a thermarest) and thus provides a lot more insulation since it is a foam. Three weekends ago I used my BA Hinman in conjunction with a 3/8 blue foam pad and was extremely warm underneath. The temp that night got down to 6*F. I would suggest adding an insluation layer to your pad system, IME the BA AirCore is for comfort, not warmth.
Dirtygaiters
03-11-2008, 23:10
Air itself does not insulate very well. If you want an inflatable pad that insulates well, you need to get one that's stuffed with insulation like primaloft, down, open cell foam, or anything else that would stop the movement of air inside the pad. Another thing you can do is put a closed-cell foam pad like the ones Gossamer Gear makes on top of your inflatable sleeping pad. That should provide insulation while the inflatable provides comfort.
On the other hand, I owned a REI Kilo Plus for a couple months, but found that it was not adequately stuffed with down and there were indeed cold spots in the bag. This was before I realized the same thing you might be realizing--that an inflatable pad alone does not provide adequate insulation--so take that criticism of REI bags with a grain of salt.