Just got back to this thread. As to the poly fill, it depends on the loft. If it's a really thick quilt and the covering is natural fiber (cotton preferably), then it's probably doing a reasonable job. If it's polyester covering then it's going to reflect somewhat. Also, the loft is small, there is going to be much less absorption. Fiberglass is about the most efficient absorber, and the higher the density the more efficient it is.