While it's fine to have it professionally cleaned, dry cleaning is not recommended, because the chemicals can damage the filling.
What Is Down?
The filling in a down jacket typically comes from geese or ducks. Goose and duck down are similar, but the down clusters found on geese are larger simply because geese are bigger birds. Down is the soft layer located under the bird's feathers and it's what they use to stay dry and warm. These down clusters are fluffy and will have several strands protruding in all directions.
According to The Ohio State University, the highest quality of down comes from geese living in cold climates. While down can range in color from gray to white, the color of the down has no impact on its insulating capabilities. Down is the warmest and lightest type of insulation for its weight.
Washing a Down Jacket
Washing your down jacket in a washing machine generally won't damage the filling as long as it's done properly. Only wash your down jacket as needed -- no more than twice a year -- to prevent the feathers from breaking. To wash your jacket, zip the zippers and secure any snaps or buttons. Turn the jacket inside out and put it in a front loading washing machine.
Wash the jacket in cold water on the gentle cycle with a small amount of gentle laundry detergent. Run the jacket through three rinse cycles altogether to ensure no soap residue is left in the down. For added protection, use a special soap made specifically for washing down-filled items.
Drying a Down Jacket
If down filling doesn't dry completely, it may begin to clump or even produce a foul odor. Place your down jacket in the dryer to dry completely. Set the heat on the dryer to low and place three clean tennis balls inside with the jacket. The balls will help to redistribute the filling and prevent clumping. Also, add a couple of dry bath towels to the dryer to help absorb moisture during the drying process.
Run the jacket through a complete dry cycle on low heat. Take it out of the dryer and shake it out gently to move the filling around. Put the jacket back in the dryer and run it through at least one more dry cycle to ensure the filling is completely dry. Depending on the size of the jacket, several drying cycles may be necessary to completely dry the down filling. Remove the jacket and shake it out after each drying cycle to keep the filling from clumping.
Other Considerations
Avoid washing your down jacket in a top-loading washing machine. The agitator bar in the washer can easily damage the jacket. Instead, always use a front-loader, which doesn't have an agitator, to protect the coat. Inspect the jacket thoroughly before placing it in the washer.
Take your jacket to a professional for cleaning if the exterior fabric is old, weak or deteriorated; otherwise, it may become damaged during the wash cycle. If you notice an odor coming from your down jacket after washing, don't worry. This is typical with down filling when it becomes wet. Once the jacket is completely dry, the smell should be gone.