Will a bunched up sleeping bag used as a quilt go lower?

[ky chris]

I'm going on a trip this weekend where the lows will be around 30 degrees. I have a 40 degree 800 fill bag that I feel good down to about 32 in the backyard. I'll be using a WBRR and 20 degree Lynx. Will the 40 degree bag used as a quilt go down lower since the whole circumference will be bunched up on the top?

I also have a 15 degree down bag but it is 600 fill. I'm debating taking extra clothes and the 40 bag or just the 15 bag. I only have so much room in my pack. I should probably just be safe and take the 15 but I'm still curious.

And BTW, I won't have this problem as soon as my 20 degree Burrow comes in.

[breyman]

And BTW, I won't have this problem as soon as my 20 degree Burrow comes in.

No, you won't. Just got mine today and it rocks.

Bunching up the bag will certainly add some warmth (especially if you don't allow too many air gaps in it), but I'm not sure exactly how much it will add. Maybe 10 degrees, at most. That will put you right around the temps you mentioned. If it were me, I'd add just a bit of insurance (I don't skirt too close to the lows in winter) and bring the 15* bag.