The four numbers on a down specification
Down outerwear is bought and sold on a small set of figures, and most disputes in the category come from one party meaning something different by one of them. Getting the specification written down precisely at the sampling stage is the cheapest risk control available on a down program.
| Figure | What it measures | Why it matters |
|---|---|---|
| Fill power | Volume occupied by one ounce of down (cubic inches, or the EU equivalent in cm³/30g) | Warmth per gram. Higher fill power packs smaller for the same warmth |
| Fill weight | Grams of down actually put into the garment | Total insulation. A high fill power with a low fill weight is still a thin jacket |
| Down content | Ratio of down clusters to feathers (e.g. 90/10) | Determines loft and how well the fill recovers |
| Cleanliness | Oxygen number and turbidity after washing | Controls odour and allergen risk, which matters most in the US and EU |
Fill power and fill weight are not interchangeable
This is the most common confusion in the category. Fill power describes the quality of the down — how much space it fills per unit weight. Fill weight describes how much of it is in the jacket. A jacket with 700 fill power and 80 g of fill is a light jacket. The same garment with 700 fill power and 250 g is a serious winter coat.
So a high fill-power figure in isolation tells a buyer almost nothing about warmth. Both numbers belong on the specification, and the warmth claim in the marketing should be derived from the pair rather than from the fill power alone.
Down content: what 90/10 actually means
Down content is the proportion of down clusters to feathers. Down clusters trap air and provide loft; feathers are flatter and provide less insulation per gram. A 90/10 fill is 90 percent clusters and 10 percent feathers, and it lofts and recovers noticeably better than an 80/20 of the same fill power.
Content is where specification substitution most often happens quietly, because a 80/20 fill can be engineered to hit a stated fill power while feeling and behaving differently over time. If the brief calls for 90/10, that belongs on the purchase order as an explicit figure, not as an assumption.
Baffle construction: how the fill is held in place
Down moves. Unless it is contained, it migrates to the bottom of every panel and leaves cold spots at the shoulders and chest. Baffle construction is how that is prevented, and it is chosen per panel rather than per garment.
| Construction | How it is built | Trade-off |
|---|---|---|
| Stitched-through | Outer and lining sewn directly together in channels | Lightest and simplest; creates cold bridges along every stitch line |
| Box baffle | Separate walls form three-dimensional chambers | Full loft with no cold bridges; heavier and more labour-intensive |
| Baffle with mesh wall | Two-dimensional baffle with a mesh internal wall | Weight saving over box baffle with most of the loft retained |
A technical winter jacket will typically use box or mesh baffles through the body and stitched-through construction in the sleeves and hood, where loft matters less than weight and mobility. That mixed approach belongs in the tech pack, not left to the factory to decide.
The fabric side: down-proofing and finish
Down proofing is the property that stops fine down fibres working through the weave. It is a function of fabric construction — yarn count, weave density and often a calendered or coated finish — rather than of the down itself. A jacket made from an under-specified shell will leak down from the first wear, and no amount of filling discipline will fix it.
Alongside down-proofing, decide the shell finish before sampling: matte or sheen, water-repellent treatment or untreated, and whether the garment is to be laminated or coated. Each choice changes both the look and the hand feel of the finished product.
Six-point specification checklist
- Fill power, with the standard it is measured to (US or EU) stated explicitly.
- Fill weight in grams, per size if the range varies.
- Down content ratio (for example 90/10), written as a firm figure.
- Cleanliness requirement, with the oxygen number and turbidity limits.
- Baffle construction per panel, with the stitch-line pattern on the tech pack.
- Shell fabric down-proofing standard and finish, confirmed on the production lot.
We manufacture down jackets, long down coats and down trench coats alongside our activewear ranges at our Guangzhou facility, with pattern development, panel cutting, baffle construction and pressing all managed in-house. Getting the six figures above settled before sampling is what turns a down program from a series of arguments into a repeatable product.