A website that covers the heating, ventilation and air conditioning industry (HVAC) has published a guide to replacing humidifiers manufactured by a certain company. The article contains a table that shows the new model numbers on one side, and the older model numbers on the other. In addition, the article has a table that identifies the old model number on one side, and the height and width measurements on the other. This is needed in order to see if the new unit will match the duct work opening.
Read more: Aprilaire Humidifier Replacement Guide