Best Cool Mist Humidifier For Large Room

So, you’re shopping for a cool-mist humidifier. But not the regular cool mist humidifier. You’re looking for a unit capable of serving a large room effectively.

The good news is that there are many large room cool mist humidifiers out there. Unfortunately, though, you can’t just pick the first one you come across. Otherwise, you risk choosing a product that won’t help you much. It may even worsen your indoor air situation. That – right there – is what’s called poor investment.

Instead, you need to understand how cool mist humidifiers work, the different options/styles, and how to match humidification capacity and room size. We discuss these and a lot more shortly. First, though, a few products to consider.

Buying Guide

Humidifiers are an invaluable buddy during the drier months. Although most of these months fall in the colder weather, you may also experience dry indoor air during the other seasons, depending on where you live.

Moreover, you may need a humidifier for other reasons. People with asthma and allergies, for instance, may benefit from indoor humidification throughout the year. The same applies to those with dry skin conditions, such as eczema.

A cool-mist humidifier would help solve most of these problems. Now that you’ve also determined that you need one for a large room, the following are important points to keep in mind.

How Humidifiers Work

A humidifier is an electrical appliance designed to add moisture to a room or house. They generate moisture by breaking down water particles into fine mist. This mist is then distributed throughout the intended room/space.

There are two four main categories of humidifiers, i.e., ultrasonic, impeller, evaporative, and steam. Here’s what you need to know about each type;

  • Ultrasonic humidifiers: These units employ high-frequency sound vibrations to break down water particles into fine mist streams. They produce the finest mist of all humidifier types. Ultrasonic models are the most popular of smaller-capacity humidifiers.
  • Impeller humidifiers: These humidifiers use a rotating disc to fling water at a diffuser. This process helps break water particles into fine moisture. The moisture is then sent into the room. Impeller humidifiers are very energy-efficient. But, they are also noisy, thus no longer very popular.
  • Evaporative humidifiers: A wick filter characterizes evaporative humidifiers. This wick system dips into a reservoir and absorbs water through capillarity. A fan then draws air from the room and forces it through the wet filter, breaking down the water particles into fine mist. Evaporative humidifiers are the most popular of larger-capacity units.
  • Steam humidifiers: Here, water is boiled in a tank to evaporation, and the resulting vapor is forced out of the humidifier and distributed throughout the home. Steam humidifiers stand out for their supplemental heating potential. The boiling process also naturally kills mold and bacteria.

Warm vs. Cool Mist Humidifiers

Humidifiers can also be categorized into warm and cool-mist models. As the names suggest, the difference lies in the temperature of the mist. Cool mist humidifiers generate mist at room temperature while warm-mist humidifiers produce warm mist generated through a heating process.

Pros and Cons of Cool Mist Humidifiers

Cool mist humidifiers are the more popular of the two options for several reasons. The following are some of the advantages and challenges associated with cool mist humidifiers.


  • No burn risk: This is the biggest advantage of cool mist humidifiers. Unlike warm mist humidifiers that boil water to evaporation, they break down water at room temperatures. Therefore the inherent burn risks associated with warm mist humidifiers are absent.
  • Increased safety around kids: The absence of burn and scalding risks is particularly valuable in families with kids and pets. No matter how careful you are, kids may sometimes find themselves close to the humidifier. Imagine them getting too close to a warm-mist humidifier with boiling water inside! It’s too much risk, right? Cool mist humidifiers are much safer.
  • A better option for night use: If you intend to use the humidifier overnight when you’re asleep, a cool-mist model is a much safer option. You don’t want near-hot air floating around the house when you’re sleeping. Worse still, what happens if the unit malfunctions and the temperature regulator stops working? You’d be exposed to extremely hot moisture.
  • Minimal energy consumption: Humidifiers, in general, don’t consume a lot of electricity – until you get to war-mist models. These units feature heating elements that draw a lot of electricity. The result is usually higher energy bills.


  • Mold and bacterial: The main issue with cool mist humidifiers is mold, mildew, bacteria, and other harmful microorganisms. In warm mist humidifiers, these organisms are killed during the boiling process. Thus, you don’t even need to worry about them. However, in cool mist humidifiers, special steps need to be taken to prevent or kill the microorganisms.

Sizing a Large Room Cool Mist Humidifier

So, what’s the right humidifier size for the space you’re looking to humidify? How much humidity do you need to add, and what metrics should you prioritize?

Determine your humidification needs

The first step is to determine how much moisture you need for that particular space. For this, you’ll need to consider two key factors;

  1. The size of the room: Yes, it’s a large room. But how large? To determine the room’s size, measure the length and width, and multiply the two figures. Ideally, you want to measure them in square feet.
  2. The relative humidity in the location: Humidification is all about raising indoor moisture levels to a desirable, healthy level. So, how much raising is needed? What’s the humidity level without humidification, and what’s the level you desire? The difference will tell you how much moisture you need to add.

Determining the right size humidifier

Once you’ve determined the size of your room and the necessary humidity rise, the next step is to determine the size of the humidifier required to meet those needs. The following are some humidifier capacity metrics to look at;

  • Moisture output per hour: Almost all humidifiers indicate the unit’s moisture output per hour on the product label. Better still, some units come with multiple output settings such that you can choose higher or lower mist output depending on prevailing conditions.
  • Moisture output per day: On average, you need to add approximately a gallon of moisture (not water) to every 300 square foot every 24 hours to keep indoor humidity levels in the recommended 40% to 60% range.
  • Tank capacity in gallons: Tank capacity directly impacts the humidifier’s moisture output levels and the amount of space it can serve effectively. Typically, larger tank capacities mean that unit can serve a larger space without strain.

Other Factors to Consider

As expected, though, size and type aren’t the only determinants of a good humidifier. Even when shopping for a large room humidifier, you’ll need to consider other factors. We recommend that you prioritize the following;

  • Intended use

Yes, you’re buying a humidifier for a large room. But, are there any other specifics? For is the large room one of your bedrooms? Is it the kid’s bedroom? Is it for someone with asthma? Manufacturers include extra features when designing humidifiers for specific purposes. Therefore, if you have special needs in mind, pick a humidifier made for that purpose.

  • Noise rating 

All humidifiers make a few sounds. Indeed, some of the quietest humidifiers are rated at around 23-26 decibels, about the TV sound. What you need is to pick the quietest model you can find. Ultrasonic humidifiers are some of the most silent while impeller models ten to be the noisiest. Anything under 40 decibels for a large-capacity humidifier is considered good.

  • Ease of cleaning/refilling

Although many people overlook these factors, it’s imperative to buy a humidifier that’s easy to clean and refill. Why? Because humidifiers need regular cleaning and refilling. You’re often required to rinse it daily or every 2/3 days at most and deep-clean it weekly. Pick a model that doesn’t take too much time to clean.

  • Product warranty 

Finally, any good humidifier will have a warranty. Otherwise, you’d have to through the unit away as soon as it malfunctions. A warranty allows you to replace the unit for free for specified malfunctions over a given period. Make sure it’s a long warranty that covers a lot of bases.  

Features to Consider When Choosing a Cool Mist Humidifier for a Large Room

Besides the above factors, you also need to pick a humidifier that’s easy to use and convenient. Consider the following features;

  • Anti-microbial solutions: Bacteria and mold are a significant risk when using cool mist humidifiers. What steps has the manufacturer taken to eliminate the problem? Popular solutions include UV treatment and antimicrobial filters.
  • Digital controls: All modern humidifiers are digitally controlled. They feature remote control, touch dials, and convenient digital LED control panels to monitor humidity levels and control indoor air conditions.
  • Smart control: A few ultra-modern humidifiers are also smart enough to connect to Wi-Fi networks and Wi-Fi-enabled devices. This makes them controllable from smartphone apps, PCs, and tablet devices. Smart humidifiers may also be compatible with Amazon Alexa and Google Home.
  • Humidistat: The humidistat is a device designed to detect humidity levels in the home and automatically communicate with the humidifier to adjust moisture output levels for ultimate indoor comfort. Consider a humidifier with an in-built humidistat.
  • Safety features: Finally, a good humidifier is a safe humidifier. Vital safety features to prioritize include alerts (sound or otherwise) when the water goes below a specified level and auto-shutoff when the tank runs empty. 

Where Should You Place the Cool Mist Humidifier?

Humidifier placement is a huge topic among users. Where should you place the humidifier for maximum effectiveness while also minimizing associated risks? Unfortunately, there’s no one-size-fits-all solution. We recommend the following tips;

  • Place it away from the electrical outlet: Humidifiers produce moisture. There can also be water spills as the unit runs. If the unit is located too close to an electrical outlet, there’s a risk of the moisture or water entering the socket, creating significant dangers. The recommended distance is at least three feet.
  • Place it away from damp-able items: This means that the humidifier should be away from curtains, your bedding, sofas, bookshelves, and any other fabric or paper items. Here too, you’re advised to maintain a 3+ distance.
  • Place it a safe distance from the bed: Placing the humidifier creates a risk of over-moisturizing the air you breathe. Inhaling too much moisture is bad for your health. Again, make sure it’s located at least three feet away.
  • Raise it off the ground: Nearly all humidifiers “leak” during operation. The larger ones, especially, will have a few water drops running down the sides. Raising the unit off the floor prevents damage to the flooring material and the floor itself. Also, consider placing a soft towel under the unit to absorb any dripping water.

What’s the Best Way to Clean a Cool Mist Humidifier?

Cleaning a humidifier is a straightforward process. You’ll need vinegar or hydrogen peroxide solution, bleaching agent, plenty of water, and a brush.

  1. Begin by turning off the humidifier and unplugging it from the electrical socket. Then disassemble the unit.
  2. Soak the base and parts in diluted vinegar. At the same time, soak the tank in a bleaching agent solution. In both cases, let the parts soak for at least 30 minutes.
  3. In the respective solutions, use a soft brush to scrub the various components, making sure to reach every corner. For those with washable filters, wash them as necessary.
  4. Rinse the parts with plenty of clean water, then set them on a clean towel to dry in an open area.
  5. Reassemble the humidifier, return the filter (or replace it altogether), and refill the tank with fresh, distilled water. Now, you’re ready to use your humidifier again.


  • Does cool-mist humidification really work? Yes. Cool mist humidifiers are very effective. In fact, they’re even more popular than warm mist humidifiers because of their inherent safety.
  • Does a cool-mist humidifier make the room cold? No. On the contrary, cool mist humidifiers may even make the room feel warmer. The explanation is that heat circulates better where there’s sufficient moisture. 
  • Do cool mist humidifiers kill germs? Yes. All cool mist humidifiers feature special technologies to kill germs, bacteria, and fungus. Make sure to ask the seller about the specific technologies when shopping.
  • Can you add eucalyptus oil to a cool-mist humidifier?  It depends. Some cool mist humidifiers are designed for use with essential oils, while others aren’t. If you’d wish to add the oils, ensure to buy a model that allows for the use of these oils. 
  • Can you run vinegar through a cool-mist humidifier? This also depends on whether the humidifier is designed to use vinegar oils. Make sure to check the label an even enquire from the seller to find out more.
  • Can you add essential oils to a cool-mist humidifier? Yes, But only if it’s indicated that the unit allows for the use of essential oils. Otherwise, using essential oils in the unit may destroy the humidifier and potentially void the warranty.
  • Do cool mist humidifiers help with congestion? Yes, all humidifiers are good for congestion. If you frequently experience congestion or any other cold and flu symptoms, you may even want to buy a humidifier for your bedroom.

Product Reviews

The following are eight of the best cool mist humidifiers to consider for a large room. These units stand out for their superior performance and reliability. Also, they won’t burn a hole in your pocket.

  • Honeywell HCM -6009 Cool Moisture Console Humidifier 


  • Large, 3-gallon tank
  • Runs for 24 hours
  • Features adjustable humidistat
  • Auto shut-off for safety


  • No remote control
  • No essential oils

The Honeywell HCM-6009 is a 3-gallon water-capacity humidifier featuring two similar-size tanks, 1.5 gallons each. Together, when full, the two tanks can run for 24 hours continuously, providing soothing and invisible moisture. The two tanks are easy to refill and even easier to clean.

The humidifier features an adjustable humidistat that automatically turns it on and off to maintain set humidity levels. Additionally, it features three-speed settings allowing you to adjust moisture output as you desire. The wicking filter removes impurities from the water, reducing white dust and ensuring clean, healthy indoor air.

The unit features auto-shutoff technology that automatically shuts off the unit when the tank runs dry. A 3-year warranty backs it.

  • Vornado UH100 Ultrasonic Fan-Assisted Cool Mist Humidifier


  • Ideal for up to 600 Sq. Ft.
  • Features a humidistat
  • Three fan settings
  • Includes mineral cartridge
  • 5-year warranty


  • No remote control
  • No essential oils use

The Model UH100 from Vornado is a powerful whole-room humidifier that evenly distributes moisture throughout the entire room. It’s recommended for rooms up to 600 square feet. A built-in humidistat means the unit continuously tracks indoor climatic conditions and adjusts mist output levels accordingly for ultimate indoor comfort.

It’s a single-tank model, thus simple to handle. Cleaning and refilling are also easier in single-tank humidifiers. The tank has a one-gallon capacity and runs for 24 hours on a single refill. In total, the unit puts out 2 gallons of moisture every 24 hours.

Other key features of the UH100 include the three fan settings (High, Low, and Auto), easy-to-use push-button controls, and an auto-shutoff function.

  1. iTvanila HU-S2 Cool Mist Humidifier for Large Room 4.5L Intelligent, Floor Humidifier


  • Three mist settings
  • Smart humidistat
  • Very quiet at 26 dB
  • Remote control
  • 24-month warranty


  • No essential oils allowed

The Model HU-S2 humidifier is a leak-proof unit that ensures no wet or water damage to your floor. It also features a hidden handle at the top of the tank for easy carrying when moving it around or during refilling. The 4.5-liter (1.18-gallon) humidifier runs continuously for 50 hours on a full tank and can effectively serve a 450-square-foot room.

What truly stands out about the humidifier, though, is the external humidifier. The Hu-S2’s external humidifier is 40% more accurate than traditional, in-built humidistats. It works alongside an Auto Mode setting on the humidifier to ensure perfect indoor conditions.

Other key features of the HU-S2 include an LED light ring to indicate current room humidity levels and an incredibly low sound rating of 26 decibels.

  1. Everlasting Comfort Humidifier for Bedroom (6L) with Essential Oil Tray


  • Large, 6-liter tank
  • Runs for 50 hours
  • Features essential oil tray
  • Whisper-quiet
  • 2-year warranty


  • The fan tends to collect dust
  • LED light is small and nearly unnoticeable

This 1.6-gallon (6-liter) humidifier from Everlasting Comfort is an ultrasonic unit that produces very fine mist particles. The large tank runs for 50 hours on a single refill, making the humidifier a perfect fit for large bedrooms and apartments up to 500 square feet. An auto-shutoff function kicks in when the tank runs dry.

The unit is tranquil. As an ultrasonic humidifier, it also doesn’t require expensive filters and time-consuming filter replacements. However, it puts out strong mist streams, with up to 9 oz (270ml) per hour at maximum capacity. You’re allowed to add essential oils to an included oil tray for relaxing nights.

A 2-year warranty backs all Everlasting Comfort Humidifiers. Over that period, any mechanical damages are repaired for free. Replacements are also done at no extra charge.

  1. Homech Model HM-AH003 Cool Mist 6L, 26dB Quiet Ultrasonic Humidifier 


  • A large, 1.6-gallon tank
  • Ultra-quiet at 27 decibels
  • 360-degree rotating nozzle
  • Detachable nozzle
  • Nano-coated circuit board


  • No smart controls

A modern-looking unit with all the bells and whistles, the Homech Model HM-AH003 is easy to clean and refill thanks to a 9 cm water inlet. Pouring water into the tank is, therefore, a breeze. Also, you can fit your hand inside the inlet when washing the tank.

It’s also an impressively large unit with a 6-liter tank that can run for 100 straight hours on a single refill. Given that most room humidifiers only run for about 24 hours on a full tank, this unit sets a different mark. A dial knob control function allows you to control mist speeds as you wish. The humidifier is ideal for spaces between 100 and 430 square feet.

Other key features of the HM-AH003 include a water tank indicator, low water protection, and tank removal auto-shutoff. It’s very quiet at just 27 decibels.

  1. Pure Guardian H4750AR Ultrasonic Cool Mist Humidifier 


  • Multiple mist settings
  • Low water indicator light
  • Auto-shutoff when the tank is empty
  • Features a timer
  • Aromatherapy tray


  • No remote control
  • No humidistat

As we’ve mentioned, only a few humidifiers can run continuously for 100 hours. And then there’s the Model H4750AR from Pure Guardian that runs for 120 straight hours! It features a 2-gallon tank and is recommended for spaces up to 600 square feet. Better still, it features a directional mist nozzle for utmost convenience.

The humidifier implements Silver Clean protection technology to protect the tank from slimy mold and mildew growth. The technology also helps fight bacteria and algae. An essential oils tray is included so you can add your favorite aromatherapy oils for relaxing nights.

Other key features of the H4750Ar include LED night lights, electronic control buttons, three mist speeds, and a 12-hour timer.

  1. HemingWeigh Ultrasonic Cool Mist Humidifier with Essential Oil Vaporizer


  • Large, 4.5-liter tank
  • Remote control
  • Easy to clean
  • Sleep and Timer mode
  • Touch controls
  • Built-in aromatherapy box


  • No “free” extra filter as the description promises
  • Temperature is only in Celsius

If you know about HemingWeigh, you’ll be aware that they are a great HVAC products manufacturer. Their products are durable and relatively modern. Also, they provide incredible user support. This humidifier embodies those design ethos. It’s a 4.5-liter unit designed to run for 16-32 hours, depending on the mist setting. Ideally, you want to use the unit in spaces between 350 and 550 square feet.

The humidifier runs very quietly at a mere 32 decibels. Moreover, it features night lights, in case you love them. The unit also has a 360-degree rotating nozzle that allows you to direct moisture in a particular area without moving the humidifier. A digital control panel on the front of the unit allows for other function controls as well as displays room temperature and humidity.

This modern humidifier comes with a child lock mechanism and automatically shuts off when the water level runs too low.

  1. OPOLAR Quietest Filter-Free Digital Humidifier for Baby and Bedroom


  • Multiple mist levels
  • In-built timer
  • Touch control panel
  • Filter-free technology
  • Auto-shutoff sensor
  • 1-year warranty


  • Essential oils not allowed

Finally, the OPOLAR is another value-for-money option when shopping for a large room cool mist humidifier. It’s an ultrasonic humidifier rated for bedroom use or even the baby’s room. This should give you a hint about its sound rating – it’s very quiet at just 35 decibels.

The unit comes in an adorable design and features touch-sensitive controls and an LED display. There are three mist levels. The total run time will depend on the level you pick. On the lowest level, the 3-liter tank runs for an impressive 26 hours. The humidifier is recommended for rooms 500 square feet.

The OPOLA shuts off automatically when the water level is low, or the tank is removed. A one-year warranty backs it.


Large room humidifiers come in all shapes and styles. They even vary in capacities. It’s important to determine the exact size of the room/space you intend to humidify and pick a unit that closely matches your moisture needs. This often means considering the tank capacity and mist output per hour/day.

Additionally, you want to consider other features, including the unit’s noise rating, ease of cleaning, safety features, and convenience features. Above all, make sure a solid warranty backs the unit. Happy shopping!