In this video, Ask This Old House plumbing and heating expert Richard Trethewey shows an efficient, low-maintenance way to humidify the air.
Steps for Installing a Humidifier for the Whole House
- Disconnect the flexible supply ducts from the sides of the heat pump.
- Remove the existing main trunk from the top of the heat pump.
- Build a new sheet metal trunk.
- Cut three 4-inch-diameter holes into the top of the new main trunk.
- Over each hole fasten a take-off fitting with a balancing damper.
- Mount a louvered sheet metal elbow to the top of the heat pump, then attach the new main trunk to the elbow.
- Attach one 12-inch-diameter take-off fitting onto the side of the main trunk. Fasten a second fitting to the bottom of the trunk.
- Cut a 2½-inch hole in the back of the trunk, then insert the humidifier wand. Secure the wand to the trunk with sheet metal screws.
- Run a new copper cold-water supply line from the water heater to the humidifier.
- Connect a drain line from the humidifier to the existing drainpipe on the heat pump.
- Have a licensed electrician run a new 220-volt circuit to the humidifier.
- Control the humidifier with a humidistat set to approximately 35 or 40 percent.