Ran into this awhile ago myself. My 1/4hp (I think) took a dump, so to speak. Anyhow I go to Home Depot, was gonna' abbreviate to HD but thought that might get misconstrued, and figured I would get the 1/2hp. Well, got it home and there was no way I could make that monstrosity fit. Ended up getting a 1/3hp with sound dampening. Works great for everything I do and it is much, much quieter than the one I replaced. I think if you haven't used it a lot up until now, 1/3hp will work fine for you. The sound dampening feature is nice though. Have fun with the plumbing.
