Larry, I don't think it would be reasonable in terms of cost to retrofit an existing home with a central vac system. Certainly, people do it, but it's going to cost a pretty penny. The vacuum tubes are typically laid out along floor joists, and then rise vertically within the walls as placed per plan. The actual outlets are usually at or near electrical outlet height on the wall. If this is something you can do yourself, then the costs would be reasonable.
The actual motor and cannister are typically mounted on a wall in the basement or utility room... Hence the quiet. You can be many rooms away from the motor noise... A very pleasant by-product of a central vac system. There are two types of vac heads... One is as you describe, like a shop vac head, although typically of better quality and more sophisticated design. The other type of head is electrified, with a rotating brush for carpeting. The newer hoses have the electricity running through the hose and getting its juice from the central vac outlet itself. Non-carpeted flooring doesn't need electricity and, therefore, you'd use a different hose... Just a simple snake without electricity running through it. The downside is cost. If it breaks down out of warranty, be prepared to spend on repairs what you'd spend on a new stand-alone vacuum cleaner. --Barry
