Mens Down Jackets are perfect for cold dry days on the hill, they have an excellent warmth to weight ratio...
Mens Down Jackets are perfect for cold dry days on the hill, they have an excellent warmth to weight ratio which means they're warm without excess bulk or added weight. They also pack down really small so they're great for putting in your rucksack for when temperatures drop.
Down is made up of 100% natural feathers taken from the undercoat of a goose or duck and when they cluster together they are high lofting plumules or tufts which trap air. When worn against a warm body, the trapped air is warmed by the body and creates a warm layer. Bear in mind that if you're cold the down jacket will also stay cold.
Down is graded to distinguish between how effective it will when worn. It can be graded by measuring its Fill Power. This measures how many cubic inches 1 ounce or 25 grams of down can fill inside a lab cylindrical flask. The higher up the flask the down fills the higher its fill power. Brands will provide fill power ratings from 450 through to 900 but most outdoor jackets only go up to 800. The higher the fill power the higher quality and lighter the product will be. Higher fill power down is collected from mature geese.
Down does have a 'down' side though - don't get it wet! If down gets wet, either from moisture in the air or from rain or snow, then the feathers flatter out and can't loft meaning their insulating properties are worse than useless; when a wet layer of down is against your skin then your body temperature will fall, and fast.
Many brands such as Berghaus, The North Face, Montane and Mountain Hardwear now offer a water resistant down which means moisture from the air, rain or snow won't stop the down from lofting and trapping warm air as usual.
A new discovery are hybrid down jackets which are made of down mixed with a synthetic fibre. The synthetic fibre, in the same way, prevents the garment from compressing due to dampness and will dry more quickly.