Pad/underquilt combo guess...

**berk** · 03-15-2014, 16:05

I have an exped dm 9lw, if I put a 3/4 20* uq under it, how low do you suppose I could take it? I've had the dm alone down to 11*, and was comfy.

Reason I ask is I'm thinking about buying the above mentioned uq as my 3-season bottom insulation, adding the pad when I can pulk in cold temps....thanks!

**g2outdoors** · 03-15-2014, 16:47

I've asked the same question before. I have an exped synmat UL 7 (r-value 3.9) and a 3/4 JRB Greylock 3 (20*) UQ. I'm hoping that I can combine them and get down around 0*. Maybe someone with experience doing this can chime in.

**Ejimo** · 03-16-2014, 11:07

I've used my 40* 3/4 with a foam pad and gotten into the low 30's with ease. But I as well would love to hear from a more experienced Hanger about this.

**ShellHammock** · 03-16-2014, 13:42

That is a tough question... You are combining two different types of insulators, hoping to get each to preform at their best. Pads are essentially vapor barriers, that block the radiant heat coming off of your body, effectively holding it hostage with no where to escape. That is why people get condensation issues with pads. Quilts, down or synthetic, slows down that same radiant heat your body pumps out allowing it to pass through the insulator and the shell of the quilt. The thicker the quilt, the longer it takes that heat to pass through, and the warmer it becomes.

With the pad UQ combo, pads will be the first layer next to your body and will be able to do its job first, trapping the radiant heat from your body. There is the problem. The UQ essentially never gets any of the heat you are producing! BUT, the thickness of a quilt below a pad will also help keep convective heat loss to a minimum, so I would think that combining the two would certainly boost your lower temp limit, but you aren't getting the most efficient use out of the UQ...

Stacking pads works to boost warmth and stacking UQ also works to boost warmth; when you combine apples and oranges, you may not be getting the most efficient use out of your gear.

I don't have any experience with the down-filled pads, so maybe their shells are a more breathable material that would make that combo work more effectively?

The only way to know for sure is to go out and test! Be sure to test this sort of thing in a controlled environment, with a solid bail out plan. 10° or 0° temps are not the time to mess around miles away from help.

**berk** · 03-16-2014, 13:46

Sounds good...I've also had the pad down to -15f on the ground, so I'm good on bailout plans!

**treywilly** · 03-21-2014, 18:42

Originally Posted by berk

I have an exped dm 9lw, if I put a 3/4 20* uq under it, how low do you suppose I could take it? I've had the dm alone down to 11*, and was comfy.

Reason I ask is I'm thinking about buying the above mentioned uq as my 3-season bottom insulation, adding the pad when I can pulk in cold temps....thanks!

I think you'll get below 0, all depends on TQ!!!