Here is what you really need to know:
1) All down is not created equal. Goose down is better than duck down. Down from mature geese that live in cold climates produce larger down clusters that trap more body heat keeping you warmer as well as lofting up to produce a comforter that is puffy without weight. Fill-power is the measurement of a down cluster's ability to loft up after compression. 650 fill-power and up is considered luxury quality. The higher the fill-power the greater the thermal properties and the puffier the comforter. There is also cluster count to consider. This is the percentage of whole down clusters as opposed to pieces of broken down known as “fly”. Canadian White Goose Down is considered to be the finest in the world. Siberian, Hungarian and Polish white goose downs are premium qualities and the very rare Eiderdown, the ultimate in softness and warmth without weight, is the best down in the world.
2) Down will eventually “leak” out of anything other than a cotton cambric downproof fabric. What makes the long staple Egyptian cotton fabric downproof is not just a high threadcount but callendering. This is a natural process of compressing the fabric between giant steel rollers to fill in spaces invisible to the eye. The best cambric cotton downproof fabric comes from Germany or Switzerland. Many of the cambrics are made with a sateen finish. They are very soft,durable and breathable. Threadcounts over 300 are best and will remain downproof for 10-15 years. For Eiderdown the best ticking is Swiss Batiste the lightest of all downproof cambric cottons with the highest threadcount, sateen finish and a silky soft touch, woven specifically for Eiderdown the softest down in the world.
3) Comforters come in open stitch (Karo-Step and Ring Stitch) where the filling can move, closed stitch (baffle box, sew-through box stitches) fixing the filling into one small box, and the Baffle Channel Tri-Wall construction, a channel stitch with a triangular baffle wall to prevent unwanted shifting. The channel tri-wall, the ultimate couple friendly comforter style, is very beneficial as it allows the filling to be adjusted on one side for truly individual comfort. This is especially useful in summer, or when one person is a warmer sleeper than the other. Baffles prevent cold spots and allow premium downs to loft up to their full potential. Less filling is required in a sew-through stitch, making these comforters better for summer or very warm bedrooms.
4)The temperature of your bedroom will determine the best comforter for you. Look for a year-round goose down or Eiderdown comforter. Most high quality goose down or Eiderdown comforters are year-round for bedrooms 60 – 72 degrees.