I wash mine., haven't seen any ill effects. Just wash and dry on gentle mode.

Hot Water, Hotter the better to kill the bed mites.

I washed several of them, down and not down, every few months for the last five years. They are great but take a LONG time to dry, way more than one cycle. Tennis balls in the dryer help to fluff it. I would NOT do it in your washer if it is not made for that capacity, however, as overloading can affect your motor. Repairman told me overloading is main cause of washer failure. Anyway, yeah, I wash mine all the time. It works better if you have a high thread count on the cover to prevent feathers coming out.

Yep, I wash mine all the time, but I do it at a laundromat using the largest machine. Drying does take forever and just to make sure it's thoroughly dry I bring it home and drape it over a sofa and let it air for a couple of days.

Washer and dryer is fine. There are some companies which make a down wash ( liquid in a bottle). Might even be available from some of the stores which carr down comforters, such as Company Store and Cuddledown.