The fastest way to stop your Aprilaire humidifier

The simplest way to turn off your Aprilaire humidifier is to set the humidistat dial to the lowest setting, usually marked as "OFF" or "0%". On most models, this dial is located on the front of the unit or on the wall-mounted control panel. Turn it fully counterclockwise until it stops—the humidifier will shut down within a few minutes as the water supply cuts off.

If your model has a digital display instead of a dial, look for a power button or an on/off toggle. Press it once to power down the unit. Some digital models require you to hold the button for two to three seconds before the system responds.

For a complete shutdown—useful during storage or maintenance—you can also turn off the water supply valve behind the unit. This is a small ball valve on the water line that you turn a quarter turn to close. This method prevents any water from entering the humidifier even if the control is accidentally switched on.

Key Takeaways

  • Rotate the humidistat dial counterclockwise to the OFF or 0% position to stop the humidifier from running.
  • Digital models have a power button or toggle switch that you press once, or hold for two to three seconds, depending on the model.
  • Turning off the water supply valve behind the unit provides a complete shutdown and prevents water from entering the system.
  • The humidifier will stop producing moisture within a few minutes of being turned off, but the fan may continue briefly on some models.
  • Always check your specific model number in the manual if the controls do not match these descriptions, as Aprilaire makes several different humidifier types.

Understanding dial-based controls on older Aprilaire models

Older Aprilaire humidifiers use a straightforward rotary humidistat dial that controls both the on/off function and the target humidity level. The dial typically shows percentages from 0% to 100%, or sometimes just OFF, LOW, MEDIUM, and HIGH. To turn off the unit, you rotate this dial all the way to the left until you hear or feel it click into the OFF position.

Once the dial is set to OFF, the humidifier stops calling for water from the supply line. The unit may take a minute or two to fully stop—you might hear the water valve close with a soft click. If the humidifier has a built-in fan, it may continue running for a short time to clear moisture from the pad, but this is normal and will stop on its own.

If you cannot locate the dial or it does not turn, check whether your humidifier is mounted in the ductwork of your furnace system. Some Aprilaire models are installed directly into the HVAC system rather than as standalone units, and these may have controls located on a separate wall panel in another room.

Powering down digital and smart Aprilaire models

Newer Aprilaire humidifiers with digital displays or smartphone connectivity have a dedicated power button, usually located on the front panel or accessible through a mobile app. To turn off the unit, press the power button once. The display should show that the system is powering down, and the humidifier will stop within seconds.

If your model has a mobile app—such as the Aprilaire app for Wi-Fi-enabled units—you can also turn off the humidifier remotely from your phone. Open the app, navigate to the humidifier control screen, and select the power-off option. This is useful if you are away from home or want to turn off the system without walking to the unit.

Some digital models have a "standby" mode separate from a full power-off. Standby mode keeps the system ready to turn on again but does not actively humidify. If you want a complete shutdown, make sure you select the full power-off option rather than standby.

Shutting off the water supply for storage or maintenance

If you are storing your Aprilaire humidifier for the season or performing maintenance, turning off the water supply valve provides an extra layer of protection. Locate the small ball valve on the water line connected to the back or bottom of the humidifier. It will have a handle shaped like a lever or a small knob.

To close the valve, turn the handle a quarter turn so that it is perpendicular to the water line. You should feel resistance—do not force it. Once closed, no water can enter the humidifier even if the control dial or power button is accidentally switched on. This is especially important if you are leaving the unit unused for several months, as it prevents mineral buildup and potential water damage.

When you are ready to use the humidifier again, turn the valve handle back to align with the water line (parallel to it). Open it slowly to allow water to flow back into the system. If water does not flow after a few seconds, the line may be clogged with mineral deposits, and you may need to clean or replace the water filter.

What happens after you turn off the humidifier

After you turn off your Aprilaire humidifier, the water valve closes and the unit stops adding moisture to your home. However, the humidifier pad—the filter that holds water and allows it to evaporate—will still contain some moisture. On some models, a small fan continues to run for a minute or two to dry out the pad and prevent mold growth. This is normal and does not mean the humidifier is still on.

If your humidifier is connected to your furnace system, the furnace itself will continue to run if it is heating or cooling your home. Turning off the humidifier does not affect the furnace. The two systems are separate, and the furnace will operate independently.

If you notice that the humidifier does not turn off after several minutes, or if you hear water still flowing, check that the control dial or power button is fully in the OFF position. If the problem persists, the water valve may be stuck or faulty, and you should contact an HVAC technician or Aprilaire customer service for help.

Troubleshooting when the humidifier won't turn off

If your Aprilaire humidifier continues to run even after you have set the control to OFF, the most common cause is a stuck water valve. Mineral deposits from hard water can jam the valve, preventing it from closing completely. Try turning the dial or power button off again, waiting 30 seconds, and then turning it back on and off once more. Sometimes this cycle clears a partially stuck valve.

If the humidifier still runs, locate the water supply valve behind the unit and close it manually. This will stop water from entering the system when ready. Then contact an HVAC technician or call Aprilaire customer support at 1-800-334-6011 to report the issue. Do not attempt to disassemble the humidifier yourself, as this can damage internal components and void your warranty.

Another possible cause is a faulty control board on digital models. If the power button does not respond, try unplugging the humidifier from its electrical outlet for 30 seconds, then plugging it back in. This resets the control board. If the button still does not work after a reset, the board may need replacement, and you should contact Aprilaire support or an authorized service technician.

Seasonal shutdown and winterization tips

When you turn off your humidifier for the season—typically in late spring or early summer when outdoor humidity rises—take a few extra steps to protect the unit. First, turn off the humidifier using the control dial or power button. Then close the water supply valve behind the unit. Finally, open the access panel (if your model has one) and inspect the humidifier pad for mineral buildup or mold.

If the pad looks discolored or has a white crusty coating, it should be cleaned or replaced before you store the unit. A clogged pad can harbor bacteria and mold spores that will spread when you turn the humidifier back on in the fall. Most Aprilaire pads cost between $20 and $40 and are straightforward to swap out—straightforward slide the old pad out and slide the new one in.

Store the humidifier in a cool, dry place if you have removed it from your system. If it is built into your furnace, straightforward leave it in place with the water valve closed. When fall arrives and you are ready to turn the humidifier back on, open the water supply valve, set the control dial to your desired humidity level (usually 30% to 50% for winter), and the unit will resume operation.

Frequently Asked Questions

Will turning off the humidifier damage it?

No. Turning off your Aprilaire humidifier using the control dial or power button is the normal way to stop it and will not cause any damage. The unit is designed to be turned on and off regularly. However, if you turn it off and on repeatedly within a few seconds, you may stress the water valve, so avoid rapid on-off cycling.

Should I turn off my humidifier in summer?

Yes. Most homes do not need humidification in summer because outdoor humidity is already high. Leaving the humidifier on during warm months can make your home uncomfortably humid and promote mold growth. Turn it off when temperatures consistently stay above 70°F and outdoor humidity is above 50%.

Can I turn off just the water without turning off the power?

Yes. Closing the water supply valve behind the unit stops water from entering the humidifier while leaving the power on. The control board and fan will still draw a small amount of electricity, but no moisture will be added to your home. This is useful if you want to keep the system ready to turn on quickly without waiting for it to power up.

What if the dial is stuck and won't turn?

Do not force a stuck dial, as this can break the internal mechanism. Instead, close the water supply valve behind the unit to stop water flow when ready. Then contact an HVAC technician or Aprilaire support. The dial may have mineral deposits inside that need professional cleaning.

Does turning off the humidifier affect my furnace?

No. The humidifier and furnace are separate systems. Turning off the humidifier does not stop your furnace from heating or cooling your home. The furnace will continue to operate normally, and you can control it independently using your thermostat.