Humidifier Not Producing Mist: How To Diagnose and Fix

By: Evan Scoboria, Last updated: June 23, 2023

Humidifiers are an excellent solution to mitigate dry conditions in our homes and offices, but what happens when your humidifier stops producing mist, the visible sign that it's working as expected? Understanding why this happens is essential to troubleshooting and resolving the issue, especially since the reasons can differ depending on whether you're using an ultrasonic or evaporative humidifier.

Humidifier not producing mist

Common Reasons Why Your Ultrasonic Humidifier May Not Be Producing Mist

The operation of ultrasonic humidifiers relies on creating and releasing a fine mist, a process that might sometimes be interrupted for several reasons. If you notice that your ultrasonic humidifier is not producing mist, here are some common reasons why:

  1. Insufficient Water Levels: Ultrasonic humidifiers use high-frequency vibrations to produce a mist from the water in their tank. If the water level is too low, the transducer responsible for these vibrations cannot generate the fog. Always ensure that the water tank is adequately filled.

  2. Quality of the Water: The type of water used in your humidifier can affect its performance. Using hard water, which contains high mineral content, can cause a build-up on the ultrasonic plate leading to reduced mist output. In such cases, using distilled or demineralized water instead can solve the problem.

  3. Dirty Ultrasonic Plate: The ultrasonic plate or nebulizer, responsible for creating the high-frequency vibrations that generate mist, can get dirty or clogged over time. This might be due to mineral deposits if you are using hard water or general dirt and grime. Cleaning this part regularly can prevent this issue and keep the humidifier working efficiently.

  4. Faulty or Broken Parts: Mechanical or electrical issues can lead to a malfunctioning humidifier. These could be due to a defective fan, a malfunctioning transducer, or issues with the power supply. If the problem persists after cleaning and refilling the water tank, it might be due to a hardware malfunction.

  5. Room Conditions: The humidity level and the room's temperature can affect the mist's visibility. If the room is humid or the air is cold, the mist may condense quicker, making it less visible. This doesn't mean that the humidifier is not working; it's just that the mist isn't visible.

Identifying the cause of the problem is the first step to finding a solution. Refer to your user manual or contact the manufacturer's customer service for assistance if you need help determining the problem yourself.

Common Reasons Why Your Evaporative Humidifier May Not Be Producing Mist

Evaporative humidifiers work differently than their ultrasonic counterparts, making the reasons for the lack of mist production different. Here are some common issues that might lead to your evaporative humidifier not producing mist:

  1. Low Water Levels: Like any other type of humidifier, evaporative models need adequate water to function. If the water reservoir is low or empty, the device will not be able to produce humidity. Always ensure your humidifier has enough water. Some units offer an indication of when water levels are low. This may look like a red button, blinking light, or led glow. 

  2. Dirty or Aged Wicking Filter: The wicking filter in an evaporative humidifier plays a crucial role by absorbing water from the reservoir and providing a large surface area for it to evaporate. If this filter is clogged with dirt or minerals or has aged and hardened, it may reduce the evaporation rate, appearing as if the humidifier is not producing mist.

  3. Quality of the Water: Evaporative humidifiers are less sensitive to water quality than ultrasonic ones. However, hard water can still cause mineral deposits on the wicking filter, reducing efficiency. Using distilled or demineralized water can help prolong the life of the filter. If your filter is rigid or discolored with mineral buildup, you'll want to unplug the device, empty the reservoir, and remove and clean the filter.

  4. Faulty Fan or Motor: The fan in an evaporative humidifier pushes the air through the moistened wick, which then adds moisture to the atmosphere. If the fan or the motor is broken or malfunctioning, this process can be interrupted, causing a lack of mist.

  5. Room Conditions: Unlike ultrasonic humidifiers, evaporative humidifiers do not produce visible mist. Instead, they release humidified air. If you don't see a visible mist coming out, it doesn't necessarily mean the humidifier isn't working. You can use a hygrometer to check for changes in the humidity level of your room.

As with any appliance, regular maintenance can help avoid most of these issues and keep your evaporative humidifier running efficiently. 

Solutions for Common Mist Production Problems in Ultrasonic and Evaporative Humidifiers

Solving mist production problems in both ultrasonic and evaporative humidifiers often involves diagnosing the cause of the issue and then taking appropriate steps to resolve it.

For ultrasonic humidifiers, if the problem lies with the water level, the solution would be to refill the water tank. In case of mineral buildup due to hard water usage, consider using distilled or demineralized water or regularly cleaning the nebulizer and tank to prevent such accumulation. If the problem is with the ceramic disc or the fan, it might need replacement, and it's best to contact the manufacturer or a professional for this.

In the case of evaporative humidifiers, maintaining a sufficient water level in the tank is critical. If the wicking filter has become clogged or less effective due to age or dirt, replacing it with a new one can help restore the humidifier's performance. Using distilled or demineralized water can reduce mineral buildup on the filter and prolong its lifespan. If the fan or motor is faulty, professional repair or replacement may be required.

Remember that the room's conditions also play a role in the perceived performance of the humidifier. Evaporative humidifiers, in particular, do not produce a visible mist but instead, increase the overall humidity levels of the room. To accurately assess if your humidifier is working, use a hygrometer to measure the humidity levels before and after the unit is switched on.

As with all devices, regular care and maintenance can significantly help prevent many of these issues from occurring in the first place. Always refer to your specific model's user manual for the best care practices, and when in doubt, reach out to the manufacturer's customer service for assistance.

Solutions by Common Humidifier Brands

Frida & Baby Frida Humidifiers

If your Frida humidifier isn't producing any mist, ensure the tank is filled with water. Once confirmed, place the humidifier on a firm, flat surface. Now, turn the unit on and leave it operating for approximately five hours. This period of uninterrupted operation will reset your Frida humidifier. After the recommended time, check to see if the blinking light issue has been resolved and if the unit produces mist as expected. If this does not resolve the issue, contact the Frida support team

Equate Cool Mist Humidifiers

If you're using an Equate Cool Mist Humidifier and notice a decrease in mist production, this may be caused by overfilling or jostling, which can cause excess water to flow into the basin via the open valve, potentially hindering the ultrasonic plate's function due to high water levels.

Resolve this by emptying the water from the basin, refilling and replacing the water tank on the unit, and turning it back on. The mist output can be increased as an additional tip by turning the control knob to its maximum position.

If your unit is carried or moved around frequently, it's best to do so with an empty basin to prevent such issues. 

Vicks Filter-Free Cool Mist Humidifiers

If you're facing an issue with your Vicks Filter-Free Cool Mist Humidifier not producing mist, you should check a few crucial elements. First, note that only filter-free units, not those with filters, will have visible mist. So if your unit is filter-free and still not producing mist, start by checking if the unit is plugged in, if there's adequate water in the tank, and if the humidifier is on a level surface.

If all of the above is in order, but the problem persists, there's a chance that buildup on the unit could be the culprit. Cleaning the humidifier can help in such a scenario. Begin by turning off the unit and unplugging it. Once done, remove the water tank and empty it. Do the same for the unit's base, emptying it into your sink.

Following this, the base of the unit needs a thorough cleaning. Fill it with undiluted white vinegar, but only to a level that covers the nebulizer. Let this setup sit for about 20 minutes. You might want to extend this soaking period if the mineral buildup is significant.

While the nebulizer is soaking, take a cotton swab and wipe around it, focusing on removing the mineral deposits. Once you've done this, the vinegar must be emptied, and the base should be rinsed well with water.

Please remember that the unit shouldn't be run with vinegar; this is a cleaning process. Regularly cleaning your humidifier per these guidelines can help maintain its functionality and ensure it works efficiently.

Professional Repair and When to Seek It

While the above solutions should help resolve most issues, sometimes a professional may be needed, especially if the humidifier's motor or other electrical components are malfunctioning. Regular maintenance, such as cleaning and replacing filters, can also help prevent these issues from arising in the first place.

Frequently Asked Questions

Why is my new humidifier not producing mist?

Even new humidifiers can have mist production issues due to improper assembly, insufficient water in the tank, or an obstruction in the mist nozzle. Review your product's assembly instructions and ensure everything is put together correctly.

Why did my humidifier stop producing mist after I replaced the water?

If your humidifier stopped producing mist after a water change, the water level may be too high or too low. Also, ensure the water tank is seated correctly and aligned with the base.

Why is my ultrasonic humidifier not producing a cool mist?

The most common reason an ultrasonic humidifier stops producing cool mist is mineral deposits on the nebulizer or a broken ceramic disc. Regular cleaning or using distilled or demineralized water can prevent mineral buildup.

How can I tell if my evaporative humidifier works if it doesn’t produce mist?

Evaporative humidifiers increase room humidity by evaporating water into the air, which may not produce visible mist. Use a hygrometer to measure the humidity level in your room before and after turning the humidifier on to see if there is an increase in humidity.

Can I fix a humidifier that’s not producing mist by myself?

Many common issues can be fixed at home by maintaining an appropriate water level, cleaning the unit regularly, and changing the filter as necessary. However, it's better to consult a professional or the manufacturer if the issue is with a mechanical or electrical component.


In conclusion, while ultrasonic and evaporative humidifiers are reliable devices designed to maintain a comfortable humidity level in your home, they can occasionally face issues that prevent them from producing mist. Understanding the most common reasons behind such issues, whether it's mineral build-up, improper assembly, or a malfunctioning component, can help you troubleshoot effectively. Regular maintenance, such as cleaning and changing filters, and using the correct type of water, can go a long way in preventing these problems. If you are still experiencing issues after trying these solutions, it may be time to contact a professional or the manufacturer. With the proper care and attention, your humidifier should continue to help create a comfortable and healthy living environment.