In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to add a humidifier to a forced-air system.
Steps for Adding a Humidifier to a Forced-Air System
- Screw the humidifier to a wall near the furnace.
- Cut away insulation from the duct using a utility knife.
- Position the hole-cutting template onto the side of the duct.
- Drill a pilot hole through the duct, then cut out the hole with aviation snips.
- Secure the humidifier's steam wand to the duct with self-tapping sheet metal screws.
- Attach steam hose to the wand and to wall-mounted humidifier; secure hose with cable ties.
- Connect the flexible drain hose to the steam wand and to the humidifier.
- Run a copper drain pipe from the underside of the humidifier to the sump pump or floor drain.
- Cut and solder a copper tee fitting into a nearby cold-water pipe.
- Run new cold-water copper piping to the bottom of the humidifier.
- Have an electrician run the electrical cable to the humidifier and to the room humidistat.
- Turn on the water to the humidifier.
- Install the air-proving switch in the duct.
- Set the upper limit of humidity on the high-limit switch.
- Set room humidistat to the desired level of humidity in the house.