Down is the pinfeathers of a bird's belly and has no center quill like feathers. Down maintains warm by trapping air within thousands of tiny plumes, like fluffy insulation.

The goal is to have the lightest weight on your body yet keep you comfortably warm.

When shopping for down, check the federal label attached to comforters or pillows. It will tell you whether you're buying 'white goose down', or just 'goose down', 'duck down', 'down', or even 'assorted water fowl feathers.' White Goose Down has always been favored.

Down is rated by "fill power" -- a measure of its puffiness or "loft". The higher the fill power, the "puffier" the down.

Only consider 100% cotton shells. The higher the thread count, the more "breathability" the quilt will have. This improves "venting" and helps avoid that sweaty, clammy feeling you may get with some polyester quilts.

Next, construction. Least expensive is the "karo step" - rows of stitches in rough diamond shaped patterns across the comforter. Problems can occur if the down shifts to the comforter's ends and sides. Better is the end-to-end box stitch, which prevents the down from shifting. Best is the "baffle box". Instead of stitching the top and bottom layers of the shell to each other, each side is stitched to a series of vertical walls, or "baffles".

Baffle box stitching allows the down to puff to its maximum potential. This eliminates cold spots and enhances the down's ability to retain heat. It also prevents down from shifting to the foot or sides while the comforter is draped over the bed.

When cleaning down, always follow the care label. Generally, you may warm wash the comforter in a gentle cycle. It can also be machine dried - warm. Adding some tennis balls or wrapped sneakers helps, but be prepared for a long drying time. Down may also be professionally dry cleaned -- but check that the store is reputable and changes the cleaning solution regularly or the chemical smell may linger in the down.