You fill your ultrasonic humidifier with distilled water, turn it on, and… Nothing happens.

Don’t throw your unit out just yet, though!

I’ve seen a lot of people waste money on a new ultrasonic humidifier when they could have easily fixed their malfunctioning unit at home.

I wrote this guide so you can repair small issues with your humidifier and save money.

Read on, and I’ll tell you why your ultrasonic humidifier is not working and how to troubleshoot the most common problems.

7 Reasons Why Your Ultrasonic Humidifier Is Not Working Properly

Ultrasonic humidifiers are like any other home device and can encounter problems.

Some issues you can resolve, but others, unfortunately, mean your humidifier is gone.

I’ve listed here the most common reasons why an ultrasonic humidifier may refuse to work and told you how to fix them.

1. Not Turning On At All

An ultrasonic humidifier that won’t turn on at all has encountered some kind of power issue.

Before you do anything else, check whether the humidifier is really not powered on.

If a control or LCD screen doesn’t come on, these parts could be broken but the rest of the device may still work.

I have a friend who threw out a perfectly good portable humidifier just because the control light burned out.

If you’re sure the humidifier is not getting power, try plugging another appliance (like a fan) into the same power outlet.

The problem lies within the electricity socket if that device doesn’t turn on either.

Should the fan turn on but your humidifier remains dead, then the problem lies somewhere in its electrical circuitry.

The power cable could have also frayed inside the insulation.

Messing with the power connections can irreparably break the unit.

Note that if your ultrasonic humidifier is battery-powered, it may have simply run out of charge!

Try swapping the batteries or charging the power source before doing anything else.

TL;DR: The first troubleshooting step is to figure out if the humidifier is turning on at all and receiving power.

2. Not Producing Any Mist

When a powered-up ultrasonic humidifier is not producing any mist, you should check whether the water tank has water in it and that it’s properly in place.

It’s surprisingly easy not to slot the tank in all the way. Everyone does this mistake at least once — that includes me.

If the water tank is firmly in place, its water release valve could be clogged. In most cases, a thorough cleaning should solve that issue.

The mist nozzle can also trap impurities, like minerals or debris, which can prevent an ultrasonic humidifier from ejecting cool mist.

If you notice water vapor building up inside a transparent spout but no or less mist comes out, you will have to clean and unclog the nozzle.

Check the user manual on how de-clog your specific type of humidifier.

The diaphragm of the ultrasonic humidifier could be encrusted with mineral residue or other dirt — or a bug could’ve crawled between the plates.

I’m not kidding, that happened to me.

You may be able to fix a blocked diaphragm with a thorough cleaning.

Again, check your manual for instructions, and be careful not to break the fragile diaphragm.

Finally, the piezoelectric transducer of your device could be broken. Replacing this component is often difficult and expensive.

If this is the issue, you’re probably better off buying a new humidifier, especially if your warranty is void.

TL;DR: No mist can mean something as simple as clogged outlets to as complicated as a broken piezoelectric transducer. 

3. Your Humidifier Is Leaking Water

If you notice your ultrasonic humidifier leaking water, you should first make sure that you haven’t overfilled the reservoir tank.

That can easily lead to excess water flooding out of the machine.

Next, check whether the water tank cap is properly tightened.

You may have accidentally fastened it too loosely or its seal may be worn, allowing water to escape.

If the cap is nice and tight, then you’re probably dealing with a cracked water tank.

Even a tiny hole that’s not immediately visible can allow water to seep through.

Cracks in the water vapor spout could also allow the mist to escape from a place other than the nozzle.

This moisture can then condensate on the humidifier’s surface and leak down.

You can try to locate the water seepage and see whether you can use a sealant, super glue, or even a piece of duct tape to plug it.

My recommendation is to purchase a replacement for whatever part of the humidifier is leaking, though.

TL;DR: If condensation is not the cause of a leak, then the water tank is certainly broken. You will have to buy a replacement. 

4. Over-Or Under-Humidifying

A humidifier that’s increasing humidity levels too much or leaving your home bone-dry is likely facing a sensor issue with a built-in humidistat or hygrometer.

These sensitive devices monitor the humidity level and it’s fairly common for them to break.

Unfortunately, it’s typically not feasible to repair humidistat sensors.

They’re small and fragile parts, and few ultrasonic humidifiers are built in a way that lets you easily swap them.

I’m sorry, but if the humidity sensor is busted, you’ll just have to buy a new ultrasonic humidifier.

But what if your humidifier doesn’t have a humidity sensor?

Well, then you have an easy fix at hand. Either the humidifier placement is wrong, or you are running it for too long or not long enough!

Put your humidifier on an even surface as close to the center of the room as possible and adjust the running time based on whether the room has too little or excess moisture. Check out my humidifier placement guide for more tips.

TL;DR: Issues with internal sensors can be the cause of over or under humidification.

5. Foul Smelling Odor

A terrible smell wafting from an ultrasonic humidifier means you have to clean it!

Mold and bacteria will build up inside an unwashed device over time.

These contaminants can lead not only to foul smells but also to your humidifier introducing them into your home air.

Trust me, you don’t want to breathe in mold spores and bacteria.

I recommend taking apart your humidifier piece by piece and cleaning it with water and white vinegar.

If the cleaning doesn’t get rid of the smell, the unwelcome contaminants are so firmly lodged in place that you’re better off replacing the device.

Most ultrasonic devices are cool mist humidifiers with no heating elements, so a burning smell indicates a serious electrical problem.

Even if your device has a heating element to produce a warm mist, you shouldn’t smell burning.

This means there’s either dirt or debris on the heating element, which could lead to a fire, or the electrical circuits are malfunctioning.

Never keep using a device that stinks of singed hair and melting plastic.

TL;DR: Any foul smelling odor should be investigated as soon as possible to reduce health risks. Thorough cleaning should eliminate most odors.

6. Making A Lot Of Noise

Ultrasonic humidifiers are silent devices, so any noticeable noise indicates that something is wrong.

The most common reason for a noisy humidifier is loose screws or parts.

Disassembling the humidifier and tightening each screw could solve this problem.

Check the device manual for any instructions on how to open your ultrasonic device correctly.

Another reason could be a broken or loose vibrating membrane that allows the diaphragm plates to clatter against each other.

Not only is this noisy but it will also prevent the unit from working correctly.

The diaphragm is hard to fix or replace, so in this case I recommend buying a new device.

TL;DR: Loud and irritating noise can be attributed to as simple as loose screw all the way to a damaged diaphragm. 

7. White Dust Around Your Home

If you notice that your ultrasonic humidifier is covering your home in fine white dust, I have good news and bad news for you.

The good news is that your humidifier is not broken.

The bad news is that the white stuff is mineral dust.

Hard water can have minerals dissolved into it that will turn into dust when the water vapor evaporates into your indoor air.

The dust can pose a health hazard and impact your breathing. I’m asthmatic mineral dust is really bad for me.

Additionally, it could cause mineral deposits to build up in your ultrasonic humidifier, which can eventually break it.

If you’re seeing dust, it’s likely because you’re using tap water in the machine. Swap to distilled water for your humidifier and the dust will disappear.

TL;DR: White dust is the result of using water with high mineral concentration. Using distilled water should fix this issue.

Troubleshooting Popular Ultrasonic Humidifier Brands

Your first step to troubleshooting an ultrasonic humidifier should be to check the manual and the manufacturer’s website.

They often address the most common problems the device might face.

That said, ultrasonic humidifiers from specific manufacturers can have problems that run in the family.

Here are the most common issues I’ve encountered with popular humidifier brands.

Honeywell – Resetting The Device Helps

Many Honeywell users have noticed that resetting the device can fix small issues.

Doing so is easy — just turn the moisture control knob all the way up.

At the highest level, the humidifier should reset. Let it run for 30 minutes, turn it off and unplug it, plug it back in, and see if it works.

Visit the Honeywell manufacturing website to learn more.

Homedics – Keep Them Clean And Tidy

Every ultrasonic humidifier needs regular cleaning, but Homedics cool mist humidifiers seem even more sensitive to minerals and dirt than most.

I’ve noticed that when the humidifier hasn’t been cleaned in a while, it develops problems with auto-shutoff and other features.

I recommend cleaning Homedics humidifiers every other day to avoid these problems.

Visit the Homedics manufacturing website to learn more.

Crane – Water Tank Cap Is Often The Culprit

If your Crane ultrasonic humidifier isn’t turning on, check the water tank cap. These units refuse to turn on if the tank cap is not secured and fastened properly.

I like this great safety feature but it could confuse new users.

If the indicator lights on your unit are red instead of green, try re-fastening the cap.

Visit the Crane manufacturing website to learn more.

Pureguardian – Sensitive To Crud Accumulation

Many homeowners note that their Pureguardian models stopped working because of the crud that accumulates around the screws inside the unit.

Add cleaning around the various screws, buttons, and other components to your regular maintenance schedule.

Visit the Pureguardian manufacturing website to learn more.

TL;DR: Each brand has its own common issues. Some require resetting, other require a frequent cleaning. It is recommended you read the user manual to find out the fixes specific to your model.

How An Ultrasonic Humidifier (Should) Work

Before you start troubleshooting an ultrasonic humidifier, you should have a basic idea of how it works.

Don’t worry — I will keep this very easy to understand.

An ultrasonic humidifier is a cool mist humidifier that transforms water into microscopic water droplets.

The machine expels the cool invisible mist into your home, where it humidifies dry air as the mist evaporates.

Ultrasonic humidifiers are fairly simple devices. They consist of three main components:

TL;DR: Ultrasonic humidifiers are cool mist humidifiers that turn water into mist by vibrating it through soundwave. They do not boil water unlike the warm mist humidifiers.

Related Article: How Ultrasonic Humidifiers Work

When Is It Time To Replace Your Ultrasonic Humidifier?

Ultrasonic humidifiers tend to last approximately two to six years.

It is time to replace your ultrasonic humidifier when the unit stops working, starts facing constant problems, or there are additional features you want on a newer model.

Essentially, if cleaning and fixing the unit becomes more trouble than it’s worth, I say get a new one.

Here are some of the most common issues I recommend keeping an out for.

The Internal Tubes Are Clogged

Not many ultrasonic humidifiers have pipes or tubes in them, but some do.

A clogged tube inside your device may prevent it from producing mist, make the machine difficult to use, or you may notice the mist coming out of the device smells bad.

Internal tubes are difficult to clean and replace, so I recommend buying a new device.

There Is No Power Being Delivered

If your humidifier will not turn on, then there is a good chance that the problem is electrical or hardware-based.

Both of these issues require an expert to fix.

In my experience, it’s typically much cheaper to simply replace the unit.

The Vibrating Membrane Has Broken

If the diaphragm of your ultrasonic humidifier breaks, you will have to buy a new device.

Replacing or repairing the vibrating membrane is often so expensive and laborious that it’s just not worth it.

Expired Warranty And Humidifier Malfunctioning

Some homeowners prefer to replace their ultrasonic humidifier when the unit runs out of warranty.

This makes the most sense when you realize that your unit doesn’t function properly, there isn’t any apparent reason why, and the warranty has expired.

TL;DR: Some telltale signs of an irreparable humidifier include clogged internal tubes, power not being delivered at all, and a damaged piezoelectric transducer. These require professional fixes.

How To Repair Your Ultrasonic Humidifier?

It may be possible to carry out basic ultrasonic humidifier repair tasks at home if you’re a handy DIY mechanic.

Here are my best repair tips and tricks for ultrasonic humidifiers.

If the humidifier works, congratulations — you’ve successfully repaired it! If not, I recommend consulting the user’s manual, hiring a professional mechanic, or getting a new machine.

TL;DR: While there are some easy DIY fixes you can apply such as cleaning the humidifier thoroughly, it is highly advised to seek professional help. 

So, Did You Find The Humidifier Fix?

Ultrasonic humidifiers are my favorite units, but they are prone to some inherent problems.

Some of them are easy to solve with a bit of elbow grease and DIY spirit, but others can spell doom for your humidifier.

With my guide, you can now diagnose and troubleshoot the most common ultrasonic humidifier issues.

However, the best defense against developing difficult problems is to regularly clean and maintain your humidifier.

This way, you can enjoy clean air and keep your airways moisturized, skin soft, and air virus-free for years to come.