I recently moved into a little house that has forced air heating. I moved there in September and thankfully, there was no need for heat. Well, now it is starting to get cold and so I turned on the heat. The noise that I get is incredible. It's like someone is pounding on the floor. Also, the floor in the living room, right above the unit I am sure, shakes. I don't want to say that it is a rattling, because it's much louder than that. So loud, that I can't watch TV in the living room. It shakes so bad that the spackle I just put on some cracks above the door, cracked again. I guess I know where they came from. Now the heat works great, keeps my place nice and toasty. My question is, does anyone know what might be causing this horrible sound? What possible solutions can anyone give me? This noise is driving me nuts!!