Try using a rebreather mask in cold weather....You can even have your head under the quilt with no condensation using one of these...Search for info, as this is an old subject that comes up this time of year.
PS... Your lungs will like it too as your moisture is rebreathed in the warmed air, eliminating dry mouth and the shock of breathing cold air.
Ounces to Grams.
... Largest supplier of camping quilts and under quilts...Home of the Original Nest
Under Quilt, and Bear Mountain Bridge Hammock.
800 595 0413