The store sell them usually have name for you to call. It is not a difficult job. Depend on your situation the job could be from 60 to few hundred dollars.
There are vent for sale at homedepot for the wall.
I have 旋风. It works ok and looks ok. There are something better out there. But usually 1 time more expensive. For cleaning they are all the same. Clean outside is easy. Inside cleaning is difficult for all of them. You need to take it apart. But does anyone ever clean inside. I don't plan to.
I used old vent too. But because of the position of the vent on the hood. I still have to modify the cabinet.
