Fill a bathtub with warm water. Make sure there is at least enough water to submerge your down bag.
Add mild soap to the water. You do not need to add any fabric softener or bleach.
Zip up your down bag and place it in the tub, allowing it to soak for about 15 to 20 minutes.
Drain the tub; press the bag with a towel if you like to squeeze out the water and soap suds. Do not wring the bag.
Rinse your bag with cold water and repeat the above steps until all the soap has been removed. It is important to get all of the suds out to avoid clumping and loss of volume in your bag.
To air dry the bag, place it on a line in the sun. Be sure to time your wash with plenty of sunlight hours to guarantee you bag is completely dry by evening.
When your bag is completely dry, place it in a storage bag large enough to provide breathing room instead of forcing it into a tiny sack. You don't want your bag to lose its volume.
Take the trip to a laundromat. Unless you happen to have a front-load washer at home, it's worth the effort to wash your down bag in one of the large machines found at most laundromats. The combination of a large down bag with a small machine can be harmful to both.
Zip up your bag and place it in the washer for one cycle, adding mild soap. You do not need to add any fabric softener or bleach.
After the first cycle is complete, send the bag through a second cycle, this time without soap. This will ensure that all the soap is removed from your bag.
Place the washed bag in the dryer and set it to low heat so as not to melt any of your bag's synthetic fibers.
If your bag comes out of the dryer looking a little lumpy, go ahead and put it back in the dryer for a longer time. This does not mean your bag is damaged, but that some of the feathers inside are still wet. Placing a tennis ball inside your bag when you put it in the dryer can help your bag retain its fluffiness.
When your bag is completely dry, place it in a bag large enough to provide breathing room. This will ensure your bag maintains its fluffiness.
