On a furnace. Between the filter and blower motor, and between the furnace and evap coil.
On a standard air handler with the blower after the coil, between the filter and coil, and then in the supply plenum.
On an electric furnace with the evap added after the blower, between the filter and blower, and between the electric strips and the coil.
On a standard air handler with the blower after the coil, between the filter and coil, and then in the supply plenum.
On an electric furnace with the evap added after the blower, between the filter and blower, and between the electric strips and the coil.