In addition to the campus “cool” factor, in the old days a down vest used to mean walking around looking like a molting Michelin man. Today’s vests are sleek, well-designed and engineered, and with a little know-how you can choose a vest that fits both function and fashion. Look for the fill power rating as well as the quantity used, and check for water resistance.

Fill Power of the Down

Look for the fill power rating to determine the quality of the down used. This vest is rated at 650. Eddie Bauer

The quality of the down is determined by its loft and insulating ability, and is measured numerically as ‘fill power.’ A higher fill power (800—900) means the down holds its loft (and insulating air) better than a down with a lower rating. However, the warmth of a garment not only depends on the quality of the down, but the quantity as well as other factors like baffling, shell permeability, etc.

Down Quantity

Some down vests mix feathers with the down. This product uses 10% feathers with 90% down. Hawke & Co.

Fill power rating alone won’t keep you warm. Warmth depends on the amount of down used. The more down, the warmer it keeps you. Down with higher fill power will keep you warmer than an equivalent amount of down with a lower fill power rating. Although not readily available with every vest, look for both the fill power rating and the quantity of down used (usually in grams) to determine how warm it will be.

Hydrophobic Down

Look for down that’s treated for water resistance. Marmot

While a vest is only one part of a layering system, because of untreated down’s propensity to lose loft and insulating ability when wet, pay attention to whether the vest uses treated down as well as wind and water-resistant fabric.