by If you’ve spent time shopping for a down comforter, you already know the listings are confusing. Fill power numbers range from 400 to 900. Some say “duck”, some say “goose”, and half don’t tell you which. Construction terms like “baffle box” and “sewn-through” appear without explanation. This guide cuts through it.
Note: This is a buying guide covering how to evaluate down comforters. If you want our top product picks, see our best down comforter roundup.
What Is Fill Power?
Fill power measures how much space one ounce of down occupies in cubic inches. A higher fill power means larger, fluffier clusters that trap more air per ounce. The range runs from about 400 (entry-level) to 900+ (expedition-grade).
- 400–500: Budget tier. More fill weight needed for equivalent warmth. Often duck down or lower-grade goose.
- 550–650: Mid-range. Good warmth-to-weight ratio. Adequate for most homes.
- 700–800: Premium. Light, lofty, durable clusters. Hotels and high-end retailers use this range.
- 850–900+: Ultra-premium. Rarely available at retail. Significant cost premium over 800.
Fill power alone doesn’t determine warmth. Fill weight — the total ounces of down inside — also matters. A 550 fill-power comforter with 50 oz of fill can be warmer than an 800 fill-power comforter with 20 oz of fill. Good listings show both numbers.
Duck Down vs Goose Down
Both are effective insulators. The practical differences:
- Cluster size: Geese are larger animals, so goose down clusters are typically larger and achieve higher fill power more consistently.
- Odor: Duck down can have a slight odor, especially in humidity. Well-washed duck down from reputable manufacturers is odor-free in practice. Poor washing is the real issue, not the species.
- Price: Duck down is less expensive. Most mid-range comforters use duck down.
- Availability: Duck down is more abundant since ducks are raised for food globally.
The practical verdict: buy by fill power and construction quality. Species matters less than sourcing and washing.
Baffle Box vs Sewn-Through Construction
Down needs to stay evenly distributed. Two main construction methods achieve this:
Sewn-Through (or “Stitch-Through”)
The top and bottom fabric layers are sewn together in a grid pattern. Simple and less expensive to manufacture. The problem: the stitching creates cold spots at each seam since down can’t fill those stitched channels. Works adequately for lightweight and summer-weight comforters.
Baffle Box
Small fabric walls (baffles) are sewn between the top and bottom layers to form three-dimensional boxes. Down fills each box completely and can loft fully. No cold seams. Better warmth for equivalent fill weight. This is the right choice for cold-climate or winter-weight comforters.
Some manufacturers use “channel” construction — a hybrid where down moves between channels. Generally falls between the two in quality.
Shell Material
The outer fabric affects feel, breathability, and whether feathers poke through.
- 300 thread count cotton: Breathable, soft, down-proof if tightly woven. The baseline for quality.
- 400+ thread count cotton: More down-proof, softer. Better for allergic sleepers.
- Microfiber/polyester: Less breathable than cotton but more affordable and easier to wash at home.
- Lyocell/Tencel blends: More moisture-wicking than cotton. Worth the premium for hot sleepers.
Thread count has diminishing returns above 400. A 300 TC tight-weave cotton often outperforms a loose-weave 600 TC.
Warmth Ratings
Most brands use a summer / all-season / winter scale. These aren’t standardized. One brand’s “all-season” may be another’s “winter”. Use fill weight (oz) and fill power together as a proxy:
- Summer weight: ~15–25 oz fill, 400–550 fill power
- All-season: ~25–35 oz fill, 550–650 fill power
- Winter: ~35–50 oz fill, 600–800 fill power
Hot sleepers should go one step lighter than their climate suggests. Cold sleepers should go one heavier.
Certifications to Look For
- RDS (Responsible Down Standard): Ensures down is sourced without live-plucking or force-feeding. Most reputable brands carry this.
- Oeko-Tex Standard 100: Shell fabric tested for harmful chemicals.
- IDFL or IDFB: Independent labs that verify fill power claims.
Care and Longevity
Down comforters can last 10–20 years with proper care.
- Use a duvet cover to protect the shell from oils and stains.
- Wash only when needed (1–2x per year with a cover). Use a front-load washer or commercial machine.
- Dry on low heat with dryer balls to restore loft.
- Store in a breathable cotton bag, not sealed plastic.
See also: our guide to best summer comforters if you run warm, and our down alternative comforter picks for allergy sufferers.
Frequently Asked Questions
What fill power should I buy?
600–700 fill power covers most people well. Below 600 is fine for warm climates or summer use. Above 750 is worth the premium only if you prioritize minimal weight.
Is goose down always better than duck down?
Not necessarily. A well-sourced, properly washed 700 fill power duck down outperforms a poorly washed 750 fill power goose down in real use. Check certifications and brand reputation over species.
Do I need baffle box construction?
For all-season or winter weights, yes. For lightweight summer comforters, sewn-through is acceptable and costs less.
How often should I wash my down comforter?
Once or twice a year if you use a duvet cover. More if you sleep without a cover or sweat heavily.
What size down comforter should I buy?
Size up one level from your mattress. A queen comforter on a queen bed has minimal overhang. A king comforter gives better coverage and allows two people to each have adequate coverage without pulling.
The Verdict
Choose Down Comforter Buying Guide 2026: Fill Power, Duck if: You value what Down Comforter Buying Guide 2026: Fill Power, Duck offers in construction, materials, and sleep technology.
Choose Goose, and More if: You prefer Goose, and More's design philosophy and material choices. Compare pricing and trial periods.
Both serve different sleep needs. Choose based on your body type, sleep position, and comfort preferences.