1. How often should I replace the humidifier Water Panel®?
   For the best performance we recommend that the Water Panel on most of our humidifiers be replaced once a year, either prior to the start or at the end of the heating season. (Aprilaire Model 400 should be changed twice during the heating season.) ^back to top

2. Can I get dimensions and other specifications for the current line of Aprilaire Humidifiers?
   Yes! Just click below to view a pdf document that lists product specifications for our current line of humidifiers: Humidifier Specifications ^back to top

3. Should our humidifier be connected with hot or cold water?
   All of our flow-through units can be connected to hot or cold water. Hot water increases the evaporative capacity of your humidifer, provides more humidity to the home and offers more flexibility in the operation of the humidifier. Some of our units can use hot air and cold water. All humidifiers need some source of heat for evaporation to take place whether it is hot water or hot air. We would recommend that if our power units are installed on the return ductwork, that they be connected to hot water, as this is their only heat source. Heat pumps and large capacity installations need hot water. Heat pumps are not hot enough for evaporation and some larger installations need maximum capacity so they will need to use both hot air and hot water. The Model 400 should be connected to cold water due to the wicking Water Panel as it cannot be guaranteed that the water will stay hot while waiting for the next heat call on the Water Panel. With any drain-though Aprilaire Humidifier connected to hot water, the heat in the water is used in the evaporation process and the water coming out of the drain will be cold to the touch. ^back to top

4. What causes condensation on my windows and how can I eliminate it?
   Cold air outside your window cools the air just inside your window more than the air in the rest of the room. If the well-humidified air just inside the window cools too much or too quickly, it can’t hold as much moisture as before and water appears on the window. To eliminate this, follow the suggested settings on your manual humidistat and adjust the setting in the morning for the anticipated night time low temperature. Another option is to upgrade your manual humidistat to an automatic humidifier control, which always maintains proper levels of humidity with no adjustment needed by the homeowner. ^back to top

5. Should we use soft water or hard water with our humidifier?
   Aprilaire humidifiers will operate properly with either hard or soft water. Connecting to hard water may leave mineral deposits on the Water Panel that are scaly and hard in nature. Connecting to soft water may leave mineral deposits that are fluffier in nature. The bottom line is the Water Panel will typically last a full heating season using either type of water. ^back to top

6. Does the outdoor sensor need to be installed in order for an automatic humidifier to work?
   If the humidifier control is installed and is operating in the automatic mode (as referenced by the faceplate on the humidifier control) the outdoor sensor is required for proper operation. The sensor is the component which sends the temperature reading back to the humidifier control and allows it to adjust the humidity level in the home accordingly. ^back to top

7. Will an Aprilaire Humidifier cause mold in my home?
   Aprilaire Humidifiers are designed to accurately control the level of humidity in the home. This is accomplished by the use of an outdoor temperature sensor that communicates with a computer equipped control over 345,000 times per day. In conjunction with a precision humidity sensor which samples the air coming back to your furnace, the Aprilaire Automatic Humidifier Control responds immediately to changing outdoor conditions. Remember, it’s just as important to shut the humidifier down when the humidity control reaches its set point as it is to deliver even more comforting humidity to the home when it’s warmer outside. The Models 400, 600, and 700 come with this automatic humidifier control that allows the humidifier to deliver the optimum amount of humidity based on outdoor conditions. This will typically range from 20% on a really cold day to as much as 45% when it’s warmer outside. This is of importance because industry data shows that mold does not grow in humidity levels below 60%. The bottom line is that no Aprilaire humidifier will contribute to the growth of mold, when installed, operated, and maintained as recommended. ^back to top

8. Why do you offer an automatic and a manual control for your humidifiers?
   As the #1 manufacturer of humidifiers in the country, we feel it is important to offer a control option for all applications. The automatic humidifier control is the top of the line when is comes to technology. The automatic humidifier control takes a reading of the outdoor temperature and adjusts the humidity level in the home based on the outdoor temperature. This is achieved by placing a sensor outside that reads the outdoor temperature over 86,000 times per day. However, we realize that there are some applications where it is impractical or impossible to run an outdoor temperature sensor to the outside. That is why we provide a high quality manual control for such applications. Having these two options gives total flexibility to meet every customer’s humidification needs. ^back to top

9. Why would one contractor recommend one humidifier unit while another one recommends a different unit?
   There are frequently several different models which will adequately humidify one’s home. Typically dealers will install a unit that they are comfortable with, have recommended to their customers for some time, and meets the technical requirements for humidification in your home. Bottom line, choose the dealer you are comfortable with; they know your heating/air conditioning system and can recommend an appropriate Aprilaire Humidifier. ^back to top