Install a humidifier to a furnace by screwing the unit to the outside of the furnace, installing the flexible duct, connecting the waterline and valve and adding the drum. Install the humidistat and adjust the water level. The procedure is the same for Lennox and other brand furnaces.
Installing the humidifier requires cutting an opening in the warm air and the return duct. Most units include a template for the opening. The opening in the cold air return allows the unit to pull air through the humidifier, add moisture and return it to the air stream that flows through the ducts to the home.
Connecting the device requires the use of sheet metal screws. Install the screws by pre-drilling holes through the humidifier, collar and the warm air duct.
The unit requires connections to the cold water supply. Most installers use a saddle valve and copper line for this connection. The saddle valve fits over the pipe with a rubber washer. Once the installer tightens it over the pipe, he turns the needle valve to pierce the pipe. Opening the needle valve then allows water to flow through the line.
Most people find setting the humidistat to 40 percent provides a comfortable humidity level. Setting the level too high encourages the growth of mold.