Aprilaire Owner's Center Frequently Asked Questions

1. Can I connect a Model 400 Humidifier to a Heat Pump system?
   Model 400 humidifiers can be installed on heat pump systems. However, due to the fact that heat pumps deliver lower temperature air to the home than gas furnaces, evaporation will be approximately 60% of rated capacity (Note: With other Aprilaire models, hot water can be used instead of cold water to maximize evaporation. However, due to the nature of the wicking water panel in the Model 400, hot water provides no extra benefit). As such, your dealer will need to take the size and age of your home into consideration to ensure the Model 400 will provide satisfactory comfort and protection through adequate humidification. ^back to top
3. Will the humidifier harm my rigid metal or flex-duct work?
   Aprilaire humidifiers are an evaporative-style humidifier. Unlike misting or atomizing humidifiers that put a water droplet into the airstream, Aprilaire humidifiers use a natural evaporation process to generate humidity. Because the humidity is a gas it passes through any air cleaner (and any blower motor as well) with no adverse effects. ^back to top
5. What kind of humidifier is the Aprilaire?
   Aprilaire humidiers are an evaporative-style humidifier. Unlike misting or atomizing humidifiers that put a water droplet into the airstream, Aprilaire humidifiers use a natural evaporation process to generate humidity. Because the humidity is a gas it passes through any air cleaner (and any blower motor as well) with no adverse effects. ^back to top
7. 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
9. Is it okay to install the air cleaner near a humidifier?
   If you own an Aprilaire Humidifier the answer is a very simple “Yes.” The humidifier will not have an adverse affect on the air cleaner since the humidity being created is vapor. If you do not own an Aprilaire Humidifier - we recommend that you contact the manufacturer of your humidifier for specific application information. ^back to top
11. My dealer is recommending a model not listed on your site. Is the unit out-of-date?
    

12. Periodically, we add features or refine some aspects of our products. When that happens, we change the model number or introduce a new model number. Models not listed in the main product sections, but still offered by dealers, have very likely been changed quite recently. They are still modern, high-performance humidifiers that will serve your home well. Your dealer is the expert in recommending the best humidifier for your home and its unique needs. The bottom line is that when you purchase an Aprilaire Humidifer, you are buying the finest whole-house humidifier available today.

13. Listed below is a description of current Aprilaire Humidifier models and the models they replaced.

14. Model Number	Description	Previous Models
    350/360	This self-contained humidifier is specifically designed for homes with radiators or baseboard heat.	Model 330
    400	This bypass humidifier features drain-free operation. The water panel evaporator is wetted by the standard flow-through system but then wicks excess water up from a small reservoir. Operation can be either manual or automatic.	Recirculating Models 445 (manual control) & 445A, 448 (automatic control)
    500	This small, manually controlled bypass model incorporates a built-in bypass damper and easy right or left discharge change-over.	Bypass Models 550 (manual control) & 350A, 558 (automatic control)
    600	This large bypass model incorporates a built-in bypass damper and easy right or left discharge change-over. Control can be automatic or manual.	Bypass Models 220, 224, 440, 560 (manual control) & 560A, 568 (automatic control)
    700	This large capacity powered model can be operated in manual or automatic mode.	Powered Models 110, 112, 760 (manual control) & 760A, 768 (automatic control)

    
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16. 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
18. 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
20. Can my Aprilaire Humidifier be upgraded to operate automatically?
    Yes, any furnace-mounted Aprilaire Humidifier, including models that are no longer a part of our current product offering, can be upgraded to fully automatic operation with the installation of the #56 Humidifier Control. You will receive up to 50% more humidity compared to a manual humidistat which will increase your home's comfort. Your Aprilaire Dealer can install this component so you can enjoy fully automatic operation - just set it and forget it! ^back to top
22. Are there problems with standing water with the Model 400?
    No. Problems associated with standing water are addressed in the design of this humidifier since it contains at most, eight ounces of water at any given time. In addition, all the water evaporates, leaving the unit dry for long periods between humidification cycles. Nevertheless, it is recommended that simple recommended maintenance be performed twice a season. ^back to top
24. How often should I clean the floats in the water panel sensor assembly in the Model 400?
    The simple maintenance of replacing the Water Panel and cleaning the scale control insert, floats and float chambers can be completed in less than 10 minutes. For proper operation, this is required twice a season. ^back to top
26. Does a drain hose have to be attached to the Model 400 humidifier?
    The Model 400 uses new technology designed to use 100% of the water entering the unit. This means there is no continuous flow of water through the unit as with Humidifier Models 600 and 700. However, there is a safety overflow connection at the base of the unit. In the unlikely event of a failure, water can safely be directed to a drain if an overflow hose is attached. ^back to top
28. Why do I have to change my Water Panel on my Model 400 Humidifier twice a year?
    To ensure peak performance the Water Panel should be replaced twice a season. Over time, the wicking capabilities (ability to draw water up the Water Panel) are reduced as minerals build up on the panel. The mid-season change means you will receive proper humidity throughout the humidification season. ^back to top
30. Can I purchase humidifier electrical components direct from Aprilaire?
    Electrical components such as solenoid valves and motors are not available for direct purchase. From a safety standpoint, and to insure proper humidifier operation, these parts should be installed by a local expert, your Aprilaire Dealer. If you need the name of a local dealer, please use the Dealer Locator. ^back to top
32. Can I purchase an Aprilaire Humidifier at a retail outlet?
    No. Aprilaire products are sold through licensed contractors as they are best suited to help you choose the right unit, install it correctly and handle any warranty situations in the unlikely event they would occur. ^back to top
34. What will it cost to install an Aprilaire Humidifier in my home?
    The cost of every installation varies based on your specific application. It is recommended that you secure competitive bids and choose the contractor that you believe best meets your needs. ^back to top
36. 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
38. What’s the difference between the Model 350 and the Model 360 Aprilaire Humidifiers?
    Both units are totally self-contained and are designed for installation in homes with electric baseboard heat, hydronic heat and even with homes with forced air heating systems with special humidification needs. The Model 350 can be hung from the floor joists in a basement where ductwork would connect to a floor vent in a central location in the home for distribution of the humidified air. The Model 360 is our through-the-wall unit and can be placed in a central location of the home in a closet. ^back to top
40. 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
42. Should I regulate the water flow to my humidifier at the saddle valve?
    No. The saddle valve is not designed to regulate the water flow. The humidifier has a water-metering orifice that is designed to regulate the water flow to the Water Panel. ^back to top
44. How much water should be flowing out the drain of my humidifier?
    The water going out the drain line serves the important process of flushing mineral deposits from the water panel. Depending on the model that you have in your home, it should take two and a half to five minutes to fill a one-quart jar. The actual time is determined by the water-metering orifice in your humidifier. If your humidifier has a yellow or white orifice it will take approximately five minutes to fill a quart jar and if it has a blue or red orifice it will take approximately two and a half minutes to fill a quart jar. ^back to top
46. Why is there water draining from my humidifier?
    All of the Aprilaire Flow-Through Humidifiers incorporate a self-flushing action. This action flushes many of the mineral deposits left on the Water Panel from the evaporation process down the drain. This also minimizes the amount of maintenance required. ^back to top
48. How often should I replace my humidifier's 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
50. 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
52. 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
54. How do I properly install my replacement Aprilaire Humidifier Water Panel®?
    The orientation of your Water Panel is important for maximum evaporation. Most Genuine Aprilaire Replacement Water Panels you purchase will have a paint dot or stripe on one of the short ends. This paint should be placed up, towards the water distribution tray, for proper operation. If your humidifier requires the #45 Water Panel, there will be no paint dot and the panel can be installed in either orientation. ^back to top
56. Will my Aprilaire Humidifier affect my Aprilaire Air Cleaner?
    Aprilaire Humidifiers use a natural evaporation process to generate humidity. Because the humidity is a gas it passes through any air cleaner (and any blower motor as well) with no adverse effects. ^back to top
58. Where can I purchase the replacement parts for my Aprilaire Humidifier?
    Your local heating and cooling contractor who installed your humidifier can help you obtain these parts, or you can search for an Aprilaire Dealer in your area using our Dealer Locator located on this site. We also offer an E-Store where you may purchase select humidifier parts. If you prefer not to order online, you can contact our parts department, toll-free at 800-931-0014 and someone will gladly assist you. ^back to top
60. 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
62. 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
64. Which humidifier should we purchase for our home?
    It is very possible that more than one model humidifier may work for your home. The most qualified person to help you decide which humidifier will best fit your needs is your local HVAC contractor. They can recommend and install the best unit for your home based on its size, age and construction. ^back to top