When it comes to jackets and sleeping bags, goose down has been the star insulation since the 1930s for its unparalleled warmth-to-weight ratio. But its kryptonite has always been moisture: get down wet and the fine, soft underfeathers clump together, eliminating the heat-trapping spaces between them. Thus, in moist environments, adventurers have typically gone with synthetic alternatives made from hydrophobic polyester fibers. Unfortunately, the plastic stuff is heavier, doesn鈥檛 pack down as well, and isn鈥檛 as warm.
But spurred by rising costs and scarcity鈥攄own is a by-product of goose meat, which is appearing on fewer menus鈥攎anufacturers have developed ways to mimic down鈥檚 coveted poofy structure by adjusting the diameter of poly strands and the way they鈥檙e tacked into 颅jackets. Thinsulate鈥檚 Featherless fill resembles frizzy clumps of hair. ThermoPlume, by PrimaLoft, contains tufts reminiscent of tiny sails. And Patagonia has constructed synthetic strands that look a lot like small feather boas. 鈥淲e鈥檝e been working with PlumaFill for ten years, but it has taken us this long to figure out how to match down鈥檚 capabilities,鈥 says Kristo Torgerson, Patagonia鈥檚 alpine global product director.
So far none of the insulations have reached the loft of the finest 900-fill down, but they鈥檝e come damn close. The PlumaFill in Patagonia鈥檚 Micro Puff jacket (above right) is as warm or warmer than 800 fill. 鈥淪ynthetic insulations have always been the ideal for outdoor-gear makers because of their ability to handle moisture, but consumers want the loft and softness of down,鈥 says Donna Veraguth, who designs apparel for Jackson, Wyoming, clothing brand Stio. 鈥淭he new synthetics have both.鈥 Veraguth sees them becoming more popular in sleeping-bag construction鈥攖hey鈥檝e already infiltrated the much larger bedding market. And that should have geese everywhere breathing a sigh of relief.
Here are three聽jackets we've been testing with next-gen insulation.聽
Montane Icarus听($199)
The Icarus uses PrimaLoft Thermo颅Plume, which is blown into two baffle sizes. So-called nano baffles under the arms and along the side of the torso provide mobility and breathability (via the stitching) where less warmth is needed. Larger baffles hold more heat across the chest and shoulders.
Marmot Featherless Hoody听($200)
Marmot quilted聽Thinsulate Featherless into dozens of small compartments to prevent it from shifting around, so there are fewer cold spots. A second layer of polyester in the chest provides extra warmth and wind resistance.
Patagonia Micro Puff听($299)
Long strands of Patagonia鈥檚 own PlumaFill are tacked into place between ten-denier fabrics for the lightest, plushest jacket here. The Micro Puff dried faster than any other synthetic-fill layer we tested. Performance like that comes at a premium, although the costs $50 less than Patagonia鈥檚 equivalent down-insulated piece.