Installing a central vacuum system in an existing home can be a bit tricky, especially when it comes to installing inlet valves and PVC tubing in the walls. Below we show you how to do this if you have access from under the floor for the horizontal runs of tubing. If you do not have under-floor access, you may be able to modify these instructions to run the tubing horizontally through the attic.

For installing a central vacuum system in new construction, a much easier job, see Installing a Central Vacuum System in New Construction.

Start by selecting locations throughout the house for the vacuum system’s inlet valves. Space the inlets so the vacuum hose can reach every corner of the house. If you will be using an electric cleaning head, make sure an electrical receptacle is within 6 feet of each inlet.

Mark the positions of the inlet valves on the interior walls at the same height as the electrical outlets. It is best to mount the receptacles next to wall studs—fittings are available for mounting valves directly to wallboard only—but it is not essential. Use an inlet valve as a template to mark the wallboard for cutting the inlet hole.

Using a keyhole saw or wallboard saw, cut the hole.

Drill a 1/8-inch-diameter hole through the floor directly below each inlet hole where the base shoe or the base molding will cover the hole. Push a wire through the bored hole so you can find the hole’s location when you go under the floor.

Go below the floor and use the wire as a reference point for measuring the location for the tubing that will go up through the center of the wall. Cut a 2-inch-diameter hole up through the floor and through the 2-by-4 bottom plate of the wall, using a hole saw. You’ll probably have to do this in stages, using a combination of cutting with the hole saw and prying out chunks of wood with a chisel. Be sure to wear eye protection throughout the entire process.

Run a suitable length of the vacuum system tubing up into the wall cavity to the inlet hole and have a helper hold it there. Go back into the room above, cement on a 90-degree elbow, and then slip the mounting plate through the hole and onto the elbow.