Sunny seems to be the most affected by the hoover. He used to hide under my bed for an hour or two. Now as soon as he sees the hoover, he'll run into my room and hide. Pepper wil usually run in there as well. I usually have to pick up Storm and put him in my room. If I don't he'll want to run in there a few minutes after I've started vacuuming. I then shut the door to my room. When I want to vacuum my room, I'll put them out in the other room. This seems to work well for them.