This comforter is filled with down and not of feathers, the heat retaining quality is enhanced. Once settled and accumulated heat, you never want to get out. Moreover, the down is much more breathable than a synthetic quilt and allows evacuation of part of the natural transpiration.
The ability to put only the duvet in 4.5 or 9.0 in one or combine the two for a quilt 13.5 is a great asset: we thus have 3 different thicknesses depending on the time of year with a single quilt.
