OKEYHAUL Spreadsheet: Down Jacket Fill Power and Fill Weight

How do fill power, fill weight and baffles differ?

Fill power describes the volume occupied by a specified amount of down under test conditions. Fill weight describes the quantity of filling used. Baffle construction describes how that filling is contained and distributed. These are different pieces of information when comparing down jackets in the OKEYHAUL Spreadsheet.

A headline fill-power number cannot tell you all three. A jacket may use lofty down in a small quantity, while another uses a different amount or arrangement. The comparison becomes more informative when you separate the filling’s measured properties from the design of the finished garment.

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What does fill power measure?

IDFL describes fill power as a volumetric test: a specified amount of filling is prepared, compressed under a prescribed load and measured. Results can be expressed using different units, including cubic inches per ounce or cubic centimetres per gram. The number is meaningful in relation to the method used.

Higher loft means the material occupies more volume for the tested amount. That is why fill power is useful when discussing insulation efficiency. It remains a property of the filling under defined conditions, rather than a complete account of a jacket’s coverage, fabric or construction.

What does fill weight tell you about a jacket?

Fill weight states how much filling is present, usually as a mass in grams or ounces. IDFL lists net fill weight as a separate test from fill power. The distinction matters because volume per unit of filling and total quantity are different measurements.

Total garment weight includes more than insulation: the shell, lining, fastenings and other components also contribute. A total weight therefore cannot simply be treated as the weight of down inside. If only one of those values is published, the other remains unspecified.

The two down measurements are most useful when read together. Fill power helps describe loft, while fill weight supplies quantity. Neither label alone gives the complete construction or a universal comparison between garments.

Why does the fill-power test method matter?

Fill-power testing includes preparation of the sample, often called conditioning. IDFL explains that measuring systems and conditioning methods vary, and that handling or compression before testing can affect the reading. Two bare numbers without that context may not be directly comparable.

This is a reason to preserve the unit and any stated method when reading a specification. Converting a number into a different unit does not automatically remove differences in preparation. A laboratory result has a scope; it should not be turned into a broader finished-garment claim without supporting information.

What are baffles in a down jacket?

Baffles are the compartments or construction used to contain the filling. Rab’s down-jacket explanation discusses different baffle sizes and distinguishes stitch-through construction from boxwall arrangements. Their role is part of how insulation is distributed through the garment.

The visible quilt pattern is therefore one part of a construction discussion. It does not disclose the fill weight in each section or provide a laboratory result for the complete jacket. A photograph of large, puffy compartments cannot supply those missing specifications.

Coverage matters as well: the body, sleeves and hood belong to the finished design. Comparing a fill label while ignoring where the insulation is placed can miss the main difference between two garments.

Does fill power tell you what temperature a jacket is suitable for?

Patagonia’s explanation explicitly separates fill power from an exact measure of garment warmth. It identifies fill quantity, distribution, other materials and construction as additional factors. A fill-power number should therefore not be converted into an unsupported promise about a particular outdoor temperature.

For an OKEYHAUL Spreadsheet down-jacket browse, use the terms to understand what a description actually supplies: a measured filling property, a quantity, or a construction detail. Keep those categories distinct and leave absent specifications unfilled rather than estimating them from puffiness or a brand name.