Tarp Condensation

Your wife's quilt is rated at 20 F but your $30 one is rated 45 F. I imagine your wife's quilt was more expensive too.

So … I think your quilt let a lot of heat through, keeping the outer surface warm. Lots of heat loss, as you noticed. Any moisture which did condense might have soaked straight in as yours probably had no DWR at all.

However, your wife's quilt, being better rated and probably more expensive, had a cooler outer surface (less heat loss) so it got more condensation. The fact that it had a better DWR meant the water all beaded up so you could see it.

The first solution is to buy yourself a quilt like your wife's!

Cheers

That is what I thought might be going on. Yes the quilt she was using was about 10x the cost of the army navy shiver box. I actually just bought the quilt for myself so I wouldn't have to worry about waking up cold any more or carrying two bags just to stay warm. The plan when we went out was to share the quilt with the cheap bag over the top.

It worked well but unfortunately almost immediately and repeatedly on the first night my wife stole the down quilt, lol. Then neither of us were as warm as we could be since both were open. So the next night I just let her have it, if I stuck her in the cheap bag I'm sure she would have never gone out with me again. Of course I was cold so I ended up sticking my legs under the quilt while in my bag and that pretty well took care of it along with wearing all my clothing.

I will definitely be buying another quilt but I'm hoping to hold out on that till either we are going up to the mountains or winter rolls around again. I was originally planning on getting a two person quilt but in light of my wife's trouble with sharing I think I'll just get her a quilt of her own.

I love sleeping out but waking up cold certainly destroys the experience.

"I wonder if a fabric coating could be made to impede the formation of dew?"

"I have wondered that also. I tried Never Wet as an experiment and if anything it allowed more condensation, not less. I guess something that would absorb the water then "liberate" it back into the air when possible.."

The dew point is determined by temperature and humidity. So there are only two ways to avoid the problem.

1. Reduce the humidity inside your shelter without changing the temperature. if the humidity is reduced the dew point temperature will drop well below the temperature inside and outside of your shelter.

2. Increase the temperature inside your shelter. If you can increase the temperature inside a tent without increasing the humidity.

I don't know of any way to reduce the humidity in your shelter. So item 1 looks impossible. More ventilation will not help since it insure the humidity inside the shelter will stay the same as the humidity outside.

However there are ways to do item 2. If you are using a tent with a separate raid fly, close the vents as much as possible. your body heat may keep the inside warm enough to to prevent condensation. Using a candle lantern may also help keep the temperature up. Again more ventilation will not help since it would let the heat out. Note if you use a lantern inside the tent you have to be careful to keep enough ventilation to prevent CO2 and CO gases from building up.

when I was growing up north of Seattle My dad got a early winters 3 person gore tex tent. At the time the original Gore Tex was Air permeable much like todays event. Later that fabric was pulled from the market because body oils would damage the fabric. Later versions of Gore Tex were not air permeable. When we used this tent in the humide Cascade mountains we always closed the vents as much as safely possible and never had any significant condensation. In boy scouts I would frequently use there PU coated waterproof tents and always had issues with condensation.

DWR appears to encourage any condensation that forms on it to turn into visible water drops. This MIT video may be of interest: