Insulation Consultation

What’s up with down? Here’s a look at nature’s original insulator and its synthetic look-alikes.

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When it comes to puffy winter jackets, imitation is not only the sincerest form of flattery, it’s also the solution to a lot of problems. Goose down—the original puffy stuffing—is a natural insulator: It’s extremely warm, it compresses and rebounds easily, and it’s durable. But it has its shortcomings, too, the most notable being that it loses its loft, and therefore its insulation capabilities, when it gets wet. Synthetic insulators (Thinsulate, Primaloft and Polarguard, to name a few), generally a blend of polyester fibers, mimic the structure and thermal efficiency of down filaments but are water-resistant. As an alternative to down, they’re a viable choice, plus they’re hypoallergenic, mildew resistant and less expensive. But they’re also heavier, bulkier and harder to pack—all drawbacks when weight, volume and layering are considerations. Now, thanks to hydrophobic laminates on shell materials, down ski apparel is experiencing a renaissance—and for good reason. Unsurpassed in its warmth-to-weight ratio (three times warmer per ounce than synthetics), down is ideal in cold-weather layering systems. Puffies—both natural and synthetic—are this season’s must-have technical insulators. Here’s a primer on the options and nine jackets guaranteed to warm you up as the mercury falls.

Fill-Power A measure of quality: The higher the fill-power, the lighter and more compressible the down. While some streetwear pieces use lower fill-power, 400 or higher is standard for technical insulators. Some jackets use a down/feather mix to reduce the price.

Loft Down filaments—which come from the fine undercoat feathers of geese and ducks—and synthetic fills—with hollow or 3-D structures—cluster together (or “loft”) to form pockets that trap warm air. Each ounce of down has about two million inter-locking filaments, but, unlike synthetics, down loses its lofting ability when wet.

Shell Fabric Usually a super-lightweight, low-density ripstop (tear-resistant) nylon coated with a durable water-repellent (DWR) finish.

Zippers, Pockets, Hoods, Powder Skirts On layering pieces, the fewer components the better, as they add weight, inhibit packability and can let water in.