I'm sure this has been talked about but search isn't being fruitful.

What would be a possible low for sleeping in just a montbell ul down inner parka and down inner pants. Then probably supplemented with a pair of synthetic bootie/socks and mits.

I would imagine its somewhere in the low 40's. Which would be nice because it would completely take away the need for a summerquilt.

I know the problem would be that with your legs you'd have less heat build up from having them split instead of together, like with gloves instead of mits for fingers.

I guess the other problem would be rolling over and having the down that was up against the pad being condensed so it would take longer to loft and heat up which might cause chills? But then you could always hop outside, do a couple jumping jacks, and it would be a good excuse to actually get up to relieve yourself.

What do you think?

It might work, but jacket plus pants plus booties plus mitts will weigh a lot more than a good UL summer quilt.

I think you'd be pushing your luck. My JRB sewn-thru Shenandoah quilt, which is accurately rated to 40-45F degrees, has 6oz of down, and weighs 15.5oz. A Montbell combo like you proposed has 4.5oz of down and weighs 15.8 oz in size medium. And then when you add in heavy socks and gloves, if you can't keep your hands up inside the sleeves, there's barely any weight savings over your Golite Ultra 20 + the jacket, since the down pants and heavy socks (3-4 oz?) aren't exactly multi-use in those temps.

I don't think the money savings would even be that great, considering the cost of UL Down pants(though I guess you could use the down pants for snow camping too) vs the cost of a lightweight summer quilt like the JRB model or the BPL synthetic quilts.

Metabolism drops a lot when you're sleeping, so what you're comfortable in awake, even at rest, may not be enough when you're sleeping. You could open your bedroom windows at night and try sleeping in the combo you've proposed to get an idea.

You can also consult this chart and this one for more ideas about what is okay for what temps.

I've done the bedroom in just the jacket on a night that was 37 and was ok. But I had my legs covered with sheets which might be warmer than the pants.

For weight savings, I'd probably bring the parka either way for around camp so it would be bringing the pants instead of the ultra 20 so that would be about 13 or 14. And then booties or just socks.

I guess its just something i'll test in the backyard.

Your bedroom was 37 degrees?

I was going along your line of thought, but settled on buying a Nunatak Arc AT from a BPL'er instead.

And that Arc AT only weights 8 oz. or so.

I alreayd have the parka and pants for winter insulation purposes so its more of a hmmm, can I make it multi-purpose?

It was 37 outside, no heat, window open so probably in the 40's in my room. I wanted to test some stuff before a trip.

Jeff just to let you know I tried a similar idea this spring. I slept in a unheated storage room with the window open. The next moring the measured tempurature in the room was still around 45 while outside it was probably in the low 30's. At any rate I was very surprised at how much heat the room held in.
I would just say before you go out on a limb with your setup you might want to make sure of the tempurature.

Edited by Cameron on 12/16/2009 22:07:41 MST.

Keep in mind that even with a window open, you will likely have far more effect from any breezes when you are camping, even in a tent than you would in a room with at least two solid walls.