What the labels mean
Down vs Down-Alternative Duvet: Fill Power, Weight, and the Cover
Down is warmth per gram. Polyester alternative is a wash-and-forget insert. Fill power 600–700 is the adult down buy; “cloud loft” on a $49 poly is a photo.
Updated 27 Aug 2026 · 6 min read · down vs down alternative duvet
Clusters versus polyester
Down is the under-plumage cluster, not the feather quill. Fill power is cubic inches one ounce occupies: 600 is good, 700 very good, 800 excellent and usually wasted on a bed you do not pack in a stuff sack. A queen all-season down insert often sits at 50–70 oz of 600–700 fill, baffle-box stitched so the fill cannot migrate into corners.
Use a washable cover; the insert stays in. That is the whole duvet versus comforter split. Alternative fill is polyester made to mimic loft. It is the right call for a vacation rental and the wrong call at down prices.
Warmth, wash, and the $49 listing
Down wins warmth-to-weight and drape. Alternative wins the 60°C wash and the “someone in the house is allergic to dust in down, not always to down itself” situation. Shell should be tightly woven cotton (down-proof, often 233–400 TC) so quills do not poke.
| Down 600–700 FP | Down-alternative | |
|---|---|---|
| Queen all-season | 50–70 oz fill, $180–$400 | $40–$120, heavier |
| Wash the insert | Rare, gentle, or pro | Hot wash is the point |
| Loft over 5 years | Recovers if you break clumps | Goes flat, especially cheap fibre |
| Packing a guest quilt | Overkill | Correct |
Feather blend is not down
“Down and feather 70/30” means 30% quill. It is cheaper, pokier, and heavier. Fine in a European winter if the shell is down-proof. Not the same as 600-fill down. If the bag will not print fill power, you are not buying down as a spec; you are buying a puffy rectangle.
Questions, answered
- Is 800-fill worth it in a duvet?
- Rarely. 800-fill is for jackets you stuff in a pack. On a bed, 600–700 fill at the right weight is warmer per dollar.
- Down alternative for allergies?
- It removes the animal protein. Many “down allergies” are dust in an unwashed insert. A cover and a wash still matter.
- Baffle box or sewn-through?
- Baffle box for down so loft is not pinched. Sewn-through is acceptable on a thin summer alternative.
