In this video, This Old House plumbing and heating expert Richard Trethewey shows how to control the temperature to every room of the house.
Steps for creating zones in a forced-air HVAC system
- Use snips to cut a hole in side of furnace duct and fasten a male fitting.
- Attach to the male fitting a flexible duct, which is connected to an electric suction fan.
- Remove the grilles from all the registers throughout the house.
- Plug up the duct openings—except one—with a foam-rubber block placed inside a plastic trash bag.
- Turn on the suction fan to create negative pressure in the ductwork.
- Fashion a parachute from a plastic grocery bag and attach to it a spool of monofilament fishing line.
- Place the parachute into the one unplugged register. The negative pressure will suck the parachute and fishing line down to the furnace.
- Remove the flexible duct from the side of the furnace and pull out the parachute.
- Disconnect the parachute and attach the air tubing to the monofilament line.
- Go to the unplugged register and reel in the monofilament to pull the air tubing through the duct and into the register. Disconnect the monofilament.
- Unplug one of the other registers, and use its foam-rubber block to plug up the register that now has the air tubing in it.
- Repeat Steps 7 through 10 to pull a length of tubing from the furnace to every register throughout the house.
- At each register attach a pneumatic damper to the end of each length of tubing.
- Disconnect the suction fan, flexible duct and male fitting from the furnace. Seal the hole with a piece of sheet metal.
- Mount a manifold to the wall beside the furnace and then connect the ends air tubing ends to the ports on the manifold.
- Next to the manifold, mount an electric air pump. Connect the air pump to the manifold with two clear plastic tubes.
- Remove all foam-rubber blocks from the registers and reinstall the grilles.
- In each room with a register, install a battery-powered sensor, which allows you to control the room temperature.
- Mount to the wall in the kitchen or living room the main display panel, which grants you control over the temperature in every room from one location.