I am planning on installing an Air King flow through humidifier.The manual says to install unit on return duct to furnace,I marked the opening to be cut but right after the unit is my electrostatic air cleaner.Do you see any problems this may cause?Will the humidified air play havoc with the air cleaner?Thanks in advance.

 

electrostatic or electronic? if the humidifier is working properly should not affect performance.

 

Is this a by-pass flow through humidifier (takes air from the return duct and sends it directly to the supply duct) or a one piece unit that returns the humidified air to the return duct?

If it is a by-pass flow through, you should have no problems with your air cleaner.

If it is a one piece type, it could cause corrosion problems on the electronic air cleaner depending on your water conditions, desired humidity level, care and maintenance of the humidifier, etc. Consult with both the humidifier and air cleaner manufacturers for proper placement of your model.

Hope this helps