We tested 27 of the best humidifiers in our Lab, evaluating them on effectiveness, noise level, design, size, ease of cleaning, and overall value. We also spoke with Melanie Carver, chief mission officer at the Asthma and Allergy Foundation of America (AAFA) to learn about the effects of humidity on asthma and allergies, as well as what features to look for in a humidifier. Our best overall choice, the Honeywell Designer Series Cool Mist Humidifier, is a straightforward and effective humidifier with a sleek design that will blend in seamlessly to any space. Keep reading for more recommendations on the best humidifiers, as well as expert tips on how to shop for and use a humidifier. This sleek and simple humidifier received high marks across the board in our testing. It uses filter-free, ultrasonic technology to release a cool mist, which was visible the instant we turned it on. The easy-to-use, adjustable mist control allows you to change the output depending on your preference. After 15 minutes of running the unit in our testing, there was no visible puddling or leaking. Plus, testers found this unit to be extremely quiet, with only some low bubbling. Special features include an auto shut-off that turns the machine off when the water runs out, a refill light, and an essential oil tray if you want to use it as a diffuser. We love the sleek design of this unit, which hides the tank while still providing an illuminated water window so you can check how full it is. The compact, vertical shape doesn’t take up much space, making this a great option for a nightstand or side table. Plus, the handle that runs the length of the tank makes it easy to carry from the sink back to the base. In terms of setup and maintenance, this unit requires no assembly, and is very easy to fill and clean thanks to its large, round tank (although it’s not dishwasher-safe). This is really a no-frills machine—it doesn’t have any smart features or a digital display, but its simple design and ultra-quiet operation make it one of the best cool mist humidifiers for a mid-sized room, such as a bedroom. Product Details:
Size: 8.8 x 8.8 x 13.2 inches Weight: 6.6 pounds Water Tank Capacity: 1.25 gallons Run Time: Up to 24 hours
RELATED: 15 Essential Oil Diffusers That Are Stylish Enough to Leave Out on Display Immediately upon turning on this humidifier in our testing, a visible mist appeared and the white indicator light switched on to signal that the machine was in use. The ultrasonic operation was practically silent during our testing, and after 15 minutes there was no leaking or puddling. We particularly loved the nozzle sprayer attachment that allows you to direct the flow of the mist to where it’s most needed. The indicator light turns red and the unit goes into standby mode when the water is running low. Once it has run out of water entirely, it automatically shuts off. Despite the fact that it’s compact enough to slide onto a shelf or side table, this humidifier has an impressive 24-hour run time. We found the setup to be very easy; however, cleanup proved a little more difficult. The reservoir’s opening wasn’t big enough to fit testers’ hands, so it requires a brush to clean. Although this humidifier doesn’t feature fancy extras like a digital display, smart device compatibility, or a humidistat, it still outperformed many higher-priced models in terms of effectiveness and design. If you’re looking for an inexpensive humidifier that can blend into small to medium spaces while still delivering powerful results, this one more than fits the bill. Product Details:
Size: 7.8 x 7.8 x 11.8 inches Weight: 2.35 poundsWater Tank Capacity: 0.66 gallonsRun Time: Up to 24 hours Real Simple / Dera Burreson
This humidifier’s compact size and lighter weight allows it to go from the office to the home with ease. Plus, it’s small enough to fit in a cup holder and has a USB plug, so you can even use it in the car during the dry winter months. In our testing, the cool mist began to appear within a few seconds of turning on the humidifier. It features two different settings—one for continuous mist and one for intermittent mist, meaning 10 seconds on and 10 seconds off. It also features an auto shut-off setting for when the water runs out. Aside from the above features, this humidifier has very few adjustable settings, which can be a good or bad thing depending on your needs. The intuitive one-button control makes it a great choice for a guest bedroom or a car, but it also means that your control over the mist output is limited. It also does not feature an essential oil tray or any smart home features. We found this humidifier to be practically silent, and thanks to its eight-hour run time, you can keep it on your desk all day without it serving as a distraction. Setup and cleanup were both a breeze in our testing—the small tank has a large, round opening that’s easy to clean without the use of a brush. If dry winter air has you wishing you could bring your humidifier with you everywhere, then this unit is your solution. Product Details:
Size: 3.4 x 3.4 x 6Weight: 0.55 poundsWater Tank Capacity: 0.06 gallonsRun Time: Up to 8 hours
For large rooms up to 505 square feet, this humidifier emits a cool and refreshing mist for as long as 24 hours at a time. In our testing it was practically silent, and the mist appeared swiftly after touching the power button. Unlike other humidifiers, the Levoit 300S has plenty of customizable features, so you have maximum control over the humidity in your space. It features a digital display with a touchscreen power button, adjustable mist settings, an aromatherapy tray, an adjustable nozzle that allows you to change the direction of the mist, and an auto mode that uses a humidity sensor to adjust your mist to balance with your home’s humidity. The digital display will even tell you the humidity level of the room at any given time. On top of all this, the humidifier features smart device compatibility: You can control it from the Vesync App, as well as Alexa and Google Assistant, which is great for those with a nursery who want to adjust the humidity from another room. Despite its large capacity, the top-fill water tank is still compact enough to fit under the bathroom faucet, and testers found it easy to fill and transport: “It got heavy when I was filling it, but it has two conveniently placed indentation/handle areas to hold onto, which makes for stable, spill-free transportation from sink to humidifier base.” We found both setup and cleanup to be very easy, thanks to the wide opening of the water tank: “Probably the easiest cleaning process of this entire test,” says one tester. For all the extra features and smart capability you get with this humidifier, it’s an unbeatable value. Product Details:
Size: 9.6 × 7.5 × 13.4 in inchesWeight: 4.3 poundsWater Tank Capacity: 1.6 gallonsRun Time: Up to 60 hours
RELATED: The Best Air Purifiers for Cleaner Air—Plus What to Look for When Buying One for Your Home This humidifier features a 100-hour run time and a number of customizable settings that will serve you well all year long. In our testing, the mist was immediately visible upon turning on the unit, and the easy-to-use LED display allows you to shuffle between three different mist flow settings. We found it to have a quiet operation, although the volume did vary between the different mist settings. We particularly liked the mist outlet that has two nozzles that spin 360 degrees, directing the mist in any direction. But where it really stands out from the rest is its temperature settings: You can choose between cool or warm mist, depending on the time of year. According to the manufacturer, this unit can humidify rooms up to 600 square feet. Our testers found the large, transparent tank easy to fill and carry, although there were some hard-to-clean nooks and crannies. Fortunately, this unit comes fully assembled with an included cleaning brush. Additional features include an adjustable humidistat that measures the humidity of the room and allows you to maintain your exact desired humidity level—making it particularly useful for indoor plants that prefer a high level of humidity. It also comes with an automatic shut-off for when the water runs out, as well as a 12-hour timer. For the numerous features and warm mist capabilities, we think this would make an excellent addition to many homes, although it’s likely too large to be a shelf unit. Product Details:
Size: 9.8 x 5.7 x 14.4 inchesWeight: 5 poundsWater Tank Capacity: 1.29 gallonsRun Time: Up to 100 hours
If you’re looking for a humidifier for a larger room or one with smart-device compatibility, we recommend the Levoit Classic 300S Ultrasonic Smart Humidifier. It emits a powerful mist for up to 24 hours and has a number of high-tech features for maximum customization.
Our Testing Process
Our Lab testers put 27 of the best humidifiers through a series of tests to determine which ones are worth buying. First, we evaluated the setup of each humidifier by timing how long it took to assemble straight out of the box. We also filled the water tank to capacity, noting how heavy the tank was when full. Once the water tanks were full, we measured the effectiveness of each humidifier by running them continually for 15 minutes, paying attention to the mist temperature, output, and adjustments. Testers also took note of how loud each unit got, including whether it produced any humming, whistling, or crackling noises. Once the humidifiers were done running, we inspected the area around them to check for any visible puddling or leaking. Our testers also evaluated the design and size of each humidifier, including whether it blends in well with its surroundings, how much room it takes up, whether the cord is long enough to reach the outlet, how user-friendly the display is, whether it includes any smart features, its water tank capacity, its run time, and more. After each use, we emptied and cleaned the tank, evaluating how easy it was to clean, including whether or not it’s dishwasher-safe. Finally, testers rated the overall value of each humidifier, considering whether the performance justified the price.
How to Shop for Humidifiers Like a Pro
Cool Mist vs. Warm Mist
Most of the humidifiers we tested—and most on the market today—are cool mist humidifiers, meaning they release room-temperature mist into the air. They make a great choice for those with kids or pets, because there isn’t a risk of burns in the event of a spill. Cool mist humidifiers are also more versatile because they can be used year-round without overheating your space during the warmer months. And because the water doesn’t need to be heated, cool mist humidifiers typically use less energy, too. The best warm mist humidifiers are just as effective at humidifying air, but unlike cool mist humidifiers, they have an internal heating element that boils the water before releasing it. You may choose to go with a warm mist humidifier during the winter months. Fortunately, you can find humidifiers with both cool and warm mist settings, such as the Lasko Quiet Ultrasonic Digital Warm and Cool Mist Humidifier.
Ultrasonic vs. Evaporative
Depending on how they produce moisture, most cool mist humidifiers fall into one of two camps: ultrasonic or evaporative. Ultrasonic humidifiers produce a cool mist by using high-frequency sound vibrations from two ceramic plates. Evaporative humidifiers feature an internal fan that pulls in air and blows it through a wick filter, causing the water to evaporate and expel into the room without producing a mist. Ultrasonic humidifiers tend to have a quieter operation (because there’s no internal fan), and they don’t have a filter to replace. However, they have more of a tendency to disperse contaminants into the air, such as minerals commonly found in tap water. You can combat this by using distilled water and regularly cleaning your humidifier. In general, ultrasonic humidifiers tend to be more expensive than their evaporative counterparts.
Size and Capacity
Different humidifiers are intended for different room sizes, with the tank size generally acting as an indicator of how much space a unit can humidify. In general, humidifiers for small to mid-sized rooms tend to hold less than about one gallon of water, while the best humidifiers for a large room will require a bigger tank capacity. Keep in mind that you will need to carry the tank to and from the sink to fill it, so you’ll want to be sure it’s comfortable to handle and not too heavy. You’ll also want to consider whether you plan to move your humidifier from room to room, or keep it in one room at all times. If portability is a factor, consider the weight of the machine. Additionally, manufacturers will usually list the run time of a machine, which is an estimate of how often you’ll need to refill the tank. This is closely related to the tank size and thus, the size of the room you’ll be able to humidify. For humidifiers with longer run times, an auto shut-off setting can be helpful: These will either shut off the unit when it runs out of water, or use a humidistat to measure the room’s humidity and then turn off the machine when the room reaches the desired level.
Noise
A quiet humidifier will hover around 30 decibels, about as loud as a soft whisper, according to the CDC. Evaporative models tend to be louder than their ultrasonic counterparts because of their internal fan. If you’re purchasing a humidifier for a bedroom or nursery, you’ll want to keep this in mind when shopping.
Cleanup
Cleaning your humidifier at least once a week is imperative to prevent bacteria growth that can be expelled into the air. To make this process easier, look for a unit that’s easy to disassemble and a water tank that’s easy to clean.
More Humidifiers to Consider
Stadler Form Oskar Humidifier: If you’re on the hunt for the best evaporative humidifier, this one performed well in our testing and released moisture into the air without any mist. However, it’s on the more expensive end of those we tested, and requires you to periodically purchase replacement filters. Dyson Purifier Humidify+Cool Formaldehyde: This three-in-one floor unit cools, humidifies, and purifies the air. It has numerous advanced features, including an automatic shut-off that can sense the air conditions and turn off the humidifier if necessary. Its price, however, rivals that of a whole-home humidifier, but it may be worth the splurge if you’re looking for a device with both air purifying and humidifying abilities.
Questions You Might Ask
How do humidifiers work?
Humidifiers work by adding moisture to the air in the form of mist or water vapor. Their mechanism for doing this can vary depending on whether they are ultrasonic or evaporative and cool mist or warm mist. All humidifiers return moisture to the air to help with dry skin, nasal congestion, temperature control, and more. “Humidifiers can help keep the relative humidity in a comfortable range while helping to keep asthma and allergy triggers at bay,” says Carver.
What are the benefits of using a humidifier?
Humidity refers to the amount of water vapor in the air and can have varying effects based on how high or low it is. “High humidity causes the air to feel warmer than it actually is and can cause you to overheat,” says Carver. “It also encourages the growth of dust mites and mold, which can trigger asthma and/or allergies. They both thrive in high humidity levels above 50 percent. Low humidity can cause your skin, eyes, nose, and lips to dry out. It can also result in a dry, sore throat, as well as worsen eczema and asthma.” Using a humidifier can help curb these symptoms by introducing moisture into your space. Many parents also choose to purchase a humidifier for a baby’s nursery, because they can help with nasal congestion and provide a soothing environment for sleeping. Humidifiers can also provide a number of benefits for your home, too. Certain house plants thrive in humid conditions. Plus, a constant level of moisture can prevent wood furniture and wallpaper from cracking.
When are the best times to use a humidifier?
Depending on where you live, humidifiers can have benefits in both the summer and winter months. The EPA recommends an indoor humidity level between 30 and 50 percent to prevent the spread of viruses and indoor air pollutants. According to Carver, the humidity levels in your home can be affected by the climate you live in, your home’s air ventilation, and your indoor activities. During the winter months, especially in dry climates, humidity levels can dip below 30 percent—so when temperatures drop, it’s the ideal time to run your humidifier. However, constantly running your AC unit during the summer months can remove moisture from the air too, so you may choose to run it year-round. If your humidifier does not feature a humidistat, Carver suggests purchasing a low-cost hygrometer to monitor your home’s humidity level. When it comes to time of day, many people choose to run their humidifiers at night. Not only does this provide ambient noise for sleeping, but it also helps alleviate the symptoms of dry air or allergies, including congestion or a dry throat.
Can you use tap water in a humidifier?
Unless the manufacturer explicitly states to use filtered or distilled water in your humidifier, it’s generally OK to use tap water. However, if you’re using tap water in an ultrasonic humidifier, and especially if you have hard water, you may notice a fine white dust being expelled out of your humidifier. These are minerals from the tap water that have broken down, leaving behind a white dust once the water evaporates. Although this dust is harmless (unless you are sensitive to dust particles), it can begin to collect on your furniture, walls, and floors. To combat this, you can switch to filtered or distilled water, or opt for an evaporative humidifier, which uses a filter to trap minerals before the water is released into the air. “Using filtered water and changing the water daily will also help prevent mold or bacteria from growing in your humidifier,” says Carver.
Take Our Word for It
This article was written by Melanie Fincher, associate commerce editor for Real Simple with nearly three years of experience writing product reviews and lifestyle content. To come up with this list, we tested 27 of the best humidifiers on the market. Melanie spent hours evaluating testing insights from our Lab tests, considering factors like setup, effectiveness, design, size, maintenance, and overall value. For expert tips on what to look for in a humidifier, she consulted Melanie Carver, chief mission officer at the Asthma and Allergy Foundation of America.
