From the numerous threads I have read at HF, my guess is that you will have condensation issues on the exterior/ exposed / outer shell material, possibly frozen to the interior side of the UQ. My reasoning is that sil (nylon or poly) are not recommended for quilts because then the quilt will not be able to breath allowing your bodies persperation to disapate into the atmosphere especially at winter temps. I would expect the same problem with the cuben fiber material as used for a quilt because it is waterproof.