5 best humidifiers for hard water

Last updated on Oct 11, 2021 Humidifiers
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Humidifiers play a significant role in our lives. They really help those with respiratory and dry skin conditions. Unfortunately, hard water poses another burden of its own and brings about other issues that you might find unpleasant. Hard water contains minerals such as calcium and magnesium. When emitted into air, they form white dust. This dust may not be harmful, but can irritate those with respiratory conditions. Similarly, when it gets onto the walls and furniture, it forms a white film, making the house look unpleasant. Additionally, white dust can clog up in humidifiers, which can affect its effectiveness. In this case, you need a humidifier that can handle hard water. We have selected some of the 5 best humidifiers for hard water. 

Table of our 5 best humidifiers for hard water

Product nameVornado EVDC300 Evaporative HumidifierHoMedics Warm & Cool Mist Ultrasonic HumidifierOptimus Warm Mist HumidifierHoneywell Top Fill Tower HumidifierSteamfast SF-920 Warm Mist Humidifier
Type of mistcoolcool and warmwarmCoolWarm
Humidification modeEvaporationUltrasonicVaporizerEvaporationVaporizer
How white dust is removedFiltersDemineralizationFiltersFiltersHeating
Tank size4 liters6.4 liters6 liters5.5 liters4 liters
Area coverage750 ft2-600 ft2-400 ft2

What is the best type of humidifier for hard water?

There are two types of humidifiers that are effective for hard water. These include a warm-mist humidifier or a cool mist humidifier with mineral filters. Choosing the best may be down to individual preferences and budget. 

Warm-mist humidifiers heat the water to create vapor. This vapor is then cooled a bit before being released into air. The heating process removes the minerals from the water and leaves them in the tank. However, this process consumes a lot of energy and a lot of white dust is left in the water reservoir. 

On the other hand, cool mist humidifiers with filters are easy to use. They use fans to blow the moist air through the filter located at the bottom. The filters trap minerals and other impurities in the water to ensure the moisture is pure. 

In case you choose cool mist humidifiers, you should note that these filters need to be frequently replaced (about every two months). For warm-mist humidifiers,  you need to be careful to avoid spills because the hot water could burn you. 

Qualities to look out for when choosing a humidifier for hard water

  • Filters. In case you choose a cool mist humidifier, you need to lookout for mineral filters. These filters play a significant role in filtering out minerals found in hard water. Not all humidifiers come with filters. So, be vigilant when choosing a humidifier. Though, this factor does not apply to warm-mist humidifiers because they do not need filters. 
  • Easiness to clean. As the humidifier ensures no minerals are emitted into the air, many of those minerals are left behind in the water tank. When minerals excessively build up in the humidifier’s water tank, they may make the humidifier get clogged. This may cause the humidifier to start malfunctioning. So, you need to clean the tank more frequently to avoid these minerals from piling up. You should know that there are specific tanks that are difficult to clean due to their shape. Therefore, you need to assess this feature before choosing any humidifier for hard water.
  • Tank size. This is also an important factor to consider. Frequent refills may not only be tiresome, but also frustrating. A larger water tank allows the humidifier to work for longer on a single fill up. This will enable you to enjoy the soothing air without stress or any pressure.  
  • Area coverage. The coverage capacity of a humidifier is also vital. You need to choose a humidifier with a coverage capacity that can match the room you intend to place it in. This will help you ensure that all the air in the room is moist enough.  

Can you use hard water in a humidifier?

Yes, you can use it. However, if you intend to use hard water in a humidifier, you should note the following. Your humidifier should have filters with the ability to remove minerals. This is mainly important for cool-mist humidifiers. Warm mist humidifiers do not need filters and can easily be used with hard water. 

How do you treat hard water in a humidifier?

Use water softeners.  These are tablets or portions that are used to remove minerals.  Some of the water softeners include salt-based systems, portable water softeners, reverse osmosis water softeners and others. You only need to drop a tablet or a small portion into the water reservoir. This will make the water soft and safe for humidifiers.

  • Is there a humidifier that doesn’t leave white dust?

Yes. Evaporative cool mist and warm mist humidifiers do not leave white dust. This is because they use an evaporation process to release vapors. The minerals in hard water are filtered out or heated and left behind as residue. This process ensures the released mist is pure and free from minerals that cause the white dust. 

Is hard water bad for humidifiers?

Yes, hard water is bad for humidifiers. Minerals from hard water can pile up in the water reservoir tank.  This build-up can clog the humidifier thus affecting the way it releases moisture into the air. 

How to get hard water off the humidifier?

Use vinegar-water solution. Mix a vinegar solution into the water in the tank. You should ensure the quantity of vinegar solution is equal to the water in the tank. Leave the mixture for a while. After some time, pour out the mixture and clean the tank with a soft cloth. 

How to prevent hard water buildup in humidifier

  • First, you should avoid letting the water in the tank completely drain out. When water reduces to a critical level, remove the tank and refill it. This is because as the water is being filtered or heated, the minerals are left behind as residue. So, by leaving some water in the tank, it prevents these minerals from sticking to the tank. When the minerals stick to the tank, it becomes harder to remove them. 
  • Secondly, always ensure you thoroughly clean the water reservoir before refilling. Use cleaning chemicals such as vinegar. Ensure you rinse the tank several times with water if you use vinegar or any other cleaning chemicals. 
  • Frequently check the filters. If they are washable, clean them effectively. If they require replacement, please do so while following the manufacturer's guidelines. 
  • Lastly, use water softeners. These are tablets or solutions used to treat hard water. When hard water is treated it leaves less residues in the reservoir. 

5 Best humidifiers for hard water

1. Vornado EVDC300 Evaporative Humidifier

Vornado EVDC300 Evaporative Humidifier
Vornado EVDC300 Humidifier

First on our list of best humidifiers for hard water is the Vornado EVDC300 humidifier. This humidifier can be a good addition to your home especially if you use hard water. This humidifier uses evaporation to put out mist. Vornado EVDC300 has a room coverage capacity of up to 750 square feet. Additionally, it comes with a 4 liter water tank. This helps the humidifier to release 11 liters of mist in 24 hours.

The EVDC300 is designed with 3 fan speed settings. These include low, high and auto. You can use the touch sensitive control panel to adjust your humidifier.  The humidifier also comes with sensors that help it monitor the humidity of a room. This allows the humidifier to determine the needed humidity and adjust the fan speed to maintain the required moisture levels.

EVDC300 uses a wick filter to ensure the evaporated water is free from white dust and minerals. The unit has a low water indicator. When the water level is very low, the indicator will light up. In case all the water gets done, the humidifier will shut off automatically. Vornado EVDC300 uses an energy smart DC motor. This makes the humidifier consume less energy.

Why Vornado EVDC300 Evaporative Whole Room Humidifier is good for hard water

  • Wick filters. This evaporative humidifier uses a wick filter to filter the moisture before it is let into the room. The filter traps minerals present in the hard water in order to prevent white dust from being released into the air.
  • Easy to clean. The structure and design of the humidifier allows for comfortable cleaning, refilling and carrying. The tank set up is simple and enables the user to easily clean it. This means, the mineral residues will not be able to build-up in the tank.
  • Area coverage. EVDC300 has the capacity to cover up to 750 square feet. This coverage is good for apartments, offices, and other large rooms. You can use hard water in your humidifier, but your room will not have any white dust films on the walls.


  • Wick filter
  • Humidistat
  • Easy cleaning
  • Large tank
  • Easy refill


  • Requires wick replacement
  • Noisy 

 2. HoMedics Warm & Cool Mist Ultrasonic Humidifier

HoMedics Total Comfort Warm & Cool Mist Ultrasonic Humidifier
HoMedics Warm & Cool Mist Humidifier

This humidifier gives you cool and warm mist options. You can run your humidifier all year round regardless of the weather. It comes with 2 water tanks to ensure prolonged runtime. The combined capacity for these tanks is 6.4 liters. This allows the humidifier to run for up to 80 hours on low settings. When the water in the tank gets low, the unit automatically shuts off. The tanks were efficiently designed for easy cleaning and refilling.

The HoMedics humidifier does not use filters. However, it is equipped with a clean mist anti-microbial technology. This helps prevent the growth of microorganisms in the tank. Similarly, it has a demineralization cartridge that helps avert mineral buildup in the tank. This cartridge also prevents white dust from settling on your floor and furniture. You can use the control buttons to adjust the intensity of mist output.

Why HoMedics Warm & Cool Mist Humidifier is good for hard water

  • Demineralization cartridge. This ultrasonic humidifier does not use filters. But the demineralization cartridge helps remove minerals in the hard water. Your room and furniture will not get filled with white dust. This is because the humidifier removes the minerals and releases mineral-free mist.
  • Easy to clean. The humidifier comes with anti-microbial technology. This prevents the growth of mold, mildew and other microorganisms. Besides, the tanks have wide openings, which makes them easy to clean. You can effortlessly insert your hand and thoroughly clean the tank.
  • Auto shut off. The humidifier will automatically shut off when the water in the reservoir reduces to a critical level. This prevents the humidifier from completely draining the water in the tank leaving the white dust piled up. By leaving some water, the minerals left behind do not stick to the tank.


  • Quiet operation
  • Demineralization cartridge
  • Dual mist output
  • Auto shut off
  • Easy to clean


  • You need to periodically replace the demineralization cartridge

3. Optimus 3.0 Gallon Warm Mist Humidifier

Optimus 3.0 Gallon Warm Mist Humidifier
Optimus Warm Mist Humidifier

This is another humidifier that can help you with hard water. It is a warm mist humidifier with a wicking vapor system. The wicking vapor system works by heating up the water and atomizing it. This makes it release pure moisture that also relieves cold symptoms.

The humidifier holds a 6 liter water reservoir. This helps it humidify a room for up to 12 hours on a single fill up. This is a large capacity humidifier as it can cover an indoor area of up to 600 square feet. Optimus has an output capacity of 11 liters of mist per 24 hours. Also, the humidifier comes with a built-in humidistat. This helps you monitor the indoor humidity levels.

Optimus U-32010 works silently. There are no bubbling or gurgling noises. You can adjust the mist output settings to either low or high. When the water in the tanks gets critically low, a refill indicator will light up. If you do not refill, the humidifier will automatically shut off when the tank is drained.

Why Optimus 3.0 Gallon Warm Mist Humidifier good for hard water

  • Water heater. Optimus U-32010 uses PTC technology to heat up the water in the tank to emit warm mist. Through heating, the mineral residue remains in the tank, and only pure vapor is released in the air. This means you will not have white dust in your room.
  • Easy to clean. Optimus U-32010’s water tank has a wide opening. You can easily insert your hand and clean it. So, the hard water residues will not build-up in the tank as you can easily clean it frequently.
  • Area coverage. This humidifier has the capacity to cover an indoor space of 600 square feet. This means the humidifier can help you breathe in moist air even though you are in a large room. The hard water will not limit the humidifier's ability to spread mist throughout your office, bedroom or open floor.


  • Quiet operation
  • Built-in humidistat
  • Auto shut off


  • Can cause burns in case it of any spillovers

4. Honeywell Top Fill Tower Humidifier

Honeywell hev620b humidifier
Honeywell tower humidifier

Honeywell top fill humidifiers are equipped with various features that can help you deal with hard water. It comes with multiple refilling methods making it convenient to use .  The tank is removable. This means you can fill via the top or you can remove the tank and refill it at the kitchen sink. The water tank has a capacity of 5.5 liters. This capacity allows the humidifier to run for up to 24 hours on low settings. The generated moisture is clear and not visible. The unit is generally designed for large rooms.

The humidifier works with a replaceable wicking filter. The wicking filter removes minerals from the water. This averts white dust build up in the rooms in which it is being used. The unit is also equipped with a protec antimicrobial cleaning cartridge. This prevents the growth of bacteria and mold in the water tank.

The Honeywell Top Fill comes with an adjustable humidistat that monitors the indoor humidity levels. Using the indicator light, the humidifier reminds the user when it’s time to refill the tank. The auto shut off feature, turns off the device when the tank runs out of water

Why Honeywell Top Fill Tower humidifier is good for hard water

  • Wicking filter. This traps minerals found in hard water thus preventing white dust from being introduced into the air. With this humidifier, you will breathe in the soothing moist air without worrying about white dust.
  • Easy to clean. Honeywell water tank has a wide opening and is removable. This makes it easy to clean and remove the mineral residues left inside. The mist it outputs will therefore be clean and safe for breathing.
  • Large water tank. This humidifier has a 5.5 liter water tank. With just one fill up, the humidifier can take you for up to 24 hours. This means you can enjoy a full night of moist air before having to refill the water tank.


  • Tank is easy to wash
  • Fairly quiet
  • Auto shut off
  • Easy to refill


  • Filter replacement is a bit costly

5. Steamfast SF-920 Warm Mist Humidifier

Steamfast SF-920 Warm Mist Humidifier
Steamfast SF-920

The final humidifier on our list that can help you with hard water is the Steamfast SF-920 warm mist humidifier. The removable 4 liter tank on this humidifier is integrated with a handle for easy removal. This large tank allows the humidifier to generate 8 liters of mist every 24 hours. The tank is designed to allow a top refill. If you are reluctant to carry the tank to the sink, you can pour in water through the top of the tank. When the tank is full, a red light will illuminate to alert you.

SF-920 humidifier comes with 2 steam settings. On maximum setting, it takes only 3 minutes to heat up. The heating element automatically shuts off, when it becomes too hot. The unit also operates quietly.

The humidifier has an aromatherapy oil ring. You can add essential oils to its oil ring to create soothing aromas in your room. It is designed for small rooms such as offices and bedrooms.

Why Steamfast SF-920 Warm Mist Humidifier is good for hard water

  • Uses Warm mist. Steamfast uses a heater to heat up the hard water. At boiling point, the vapor generated is mineral free. All minerals that were in the hard water will remain in the tank. Therefore, the mist produced will be free from white dust
  • Wide tank with top refill. This humidifier has a 4 liter tank capacity. It is designed with a wide opening that allows you to easily refill it.
  • Easy to clean. SF-920 warm mist humidifier has a wide removable tank. This allows the user to effectively clean it to prevent mineral residues from accumulating within the tank. Ultimately, this reduces the chances of emitting white dust. .


  • Max fill indicator
  • Easy to refill
  • Two steam settings
  • Auto shut off


  • Residue left in the water tank builds up quickly

In conclusion, we understand that the hard water can surely become a problem to your humidifier and the house. In this article, we have analyzed the qualities of a humidifier that can help you deal with hard water. These can guide you in choosing the best humidifier for hard water that fits your preferences. 

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