600 Fill Down Jacket Temperature Rating

The rei co op 650 down jacket is a versatile piece for a range of temperatures and activities.

600 fill down jacket temperature rating.

26 to 1 fahrenheit. Item 500675 6w7 temperature rating warmest. Fill power is diplayed in the form of a number which you ll normally find stitched somewhere on the outside of a down sleeping bag or on the sleeve of a down jacket. Like most of the parkas in our collection it features 700 fill power and 13 ounces of white goose down.

But there are ultralight 800 fill jackets that obviously aren t as warm as 700 fill jackets that have more ounces of down in them. A down fill rating of 600 for example means that one ounce of down can cover 600 cubic inches. But that doesn t automatically mean a 900 fill down jacket is warmer than a 650 fill down jacket. In theory 50g of 900 fill power down would be the same warmth as 100g of 450 fill power down.

But if you are comparing 6 ounces of 600 fill down against 3 ounces of 900 fill down the calculation becomes trickier. The process involves putting the down into a plexiglas cylinder and slightly compressing it with a weight. If jacket a is filled with 227 grams of 800 fill power and jacket b is filled with 227 grams of 700 fill power jacket a would be warmer. The down fill rating number is a measurement of down quality meaning the cubic inches of loft one ounce of the specific down produces.

For example a jacket with 6 ounces of 800 fill down will be substantially warmer than a jacket with 3 ounces of 800 fill down that s double the amount of insulation. The fill power rating value is calculated by measuring how many cubic inches an ounce of down creates at its maximum loft. Thus if two jackets contain identical amounts of down feathers by weight the jacket with the higher fill rating will very likely be warmer. A higher rating means less down fill is required to capture the same amount of heat.

Because down with a higher fill power will trap more air and create a thicker layer between your body and the environment. Although the temperature rating system has its flaws there are still other numbers figures and facts to consider when looking for a great down jacket. Very few jacket makers report fill weights though. Down insulation and weather resistant nylon join forces to help keep you warm.

Down clothing and equipment at webtogs ranges in fill power from 550 medium fill power to 900 very high fill power.