8 Best Humidifiers (Review) In 2021

Types of Humidifiers

Evaporative - In an evaporative humidifier, water from the tank is slowly absorbed by a wick filter in a separate chamber of the humidifier. Above this wick filter - which may be quite large - is a fan which draws air upward. As the air is pulled upward through the wick filter the moisture in the filter evaporates into the air. This process of evaporation causes the air to be cooled. The moist, cool air is then blown into the room by the fan. The advantages of the evaporative humidifier are that it is easy to maintain, the filter removes most minerals from the water before they can be released into the room and this type of home humidifier is usually less expensive than its ultrasonic counterpart.

Ultrasonic - In an ultrasonic humidifier, water from the tank is slowly leaked onto the surface of a metal diaphragm that is vibrating at ultra-high speeds. This vibration agitates the water causing it to break up into tiny water particles which collectively form a mist. A fan beneath the diaphragm pushes the resulting mist upward through a nebulizing chamber and out into the room. Ultrasonic humidifiers often allow you to choose either a cool or a warm mist, with many people preferring the warm mist. The advantages of this type of humidifier are the aforementioned warm mist option, the fact that there is no filter to change and the fact that they make almost no noise whatsoever.

Features to Look for in a Humidifier

Ease of Maintenance/Cleaning - Neither an evaporative or ultrasonic humidifier is going to require much by way of maintenance. That said, they are not entirely maintenance free. For the most part, maintenance includes cleaning the water tank to prevent the development of bacteria, mold or mildew and cleaning the outlets at the top of the device where the mist exits. With evaporative units, there is the added chore of occasionally having to change the wick filter, which is really more filter than it is wick. Because they don’t use a filter ultrasonic humidifiers are normally a little easier to clean and maintain. But the difference isn’t all that great. The most important thing with any humidifier is to make sure the tank and mist outlets are clean and free of mold or bacteria. If you use the device on a regular basis this cleaning should be done about once a week.

Run Time/Capacity - Run time - or operational time as it’s often referred to - is the length of time the device will operate continually before it runs out of the water. This time will vary greatly depending on the setting and the size of the water tank. A humidifier with a small tank that is run on high will run out of water in a matter of just a few hours. Conversely, a humidifier with a large tank that is run on low may operate continually for as long as 50 hours. If you are purchasing a humidifier primarily to run it throughout the night while you sleep you would be wise to purchase one with a larger water tank. Say, 1 gallon or more. If you just want a humidifier to run in the background while you’re working out or cooking a 1-liter tank, or even smaller, should suffice.

Room Coverage - Before you select a humidifier you need to determine which room you’ll be using it in. The size of the space will go a long way toward determining the size of the humidifier. In general, a small room is considered anything less than about 300 square feet. Anything up to about 500 square feet is considered a medium sized room. While rooms up to 1,000 square feet are considered large. Measure the room you have in mind and then check to make sure the home humidifier you have your eye on will be appropriate for that size room. It should give some indication on the box or in the literature how many square feet it is designed to cover.

Health Benefits - A health benefits of a humidifier are often measured in a negative sense. That is, you can tell your humidifier is working if you do not spend the winter months slipping from cold to cold, if your allergies or asthma are in check, if you are not waking up with sore, dry eyes and if your skin is not shriveling up like a prune while you sleep. If the humidifier is doing the job it is intended to do you should be sleeping well and waking up refreshed.

Noise - A humidifier is a mechanical device and as such, it would be unrealistic to expect even the best humidifiers to be completely silent. However, in recent years advances in engineering have resulted in humidifiers that are often so quiet you won’t realize they have been running until you turn them off. This is especially true of the best ultrasonic humidifiers. Since the fan they use is smaller than the fan you’ll typically find in an evaporative humidifier and the fact that it is buried deep inside the device, the ultrasonic humidifier is the closest thing to silent you’ll find. For this reason, many people prefer them for their bedroom and then get a less expensive evaporative humidifier for the public spaces in their house.

Cool vs Warm Humidifier - Evaporative humidifiers typically release a cool mist into the air. Some people find this quite refreshing while others find it a bit uncomfortable. Those that are not enamored of the cool mist can choose an ultrasonic humidifier since many of them offer a warm mist option. With the warm mist option, a heating module is embedded in the device that heats up the water before it is passed over the nebulizer and is released into the room. The warm mist typically enters the room at about 104 degrees Fahrenheit before gradually cooling. The ultrasonic humidifier typically lets you choose whether you receive a warm or cool mist. While with the evaporator it is strictly cool mist.

Filters - Filters are also called “wicks” or “wick filters”. They can be found in evaporative humidifiers and their job is not only to absorb water and release it into the air by way of evaporation but also to remove chemicals and minerals from the water so that you don’t breathe them in. Many filters have antimicrobial, antibacterial and antiviral properties that prevent these nasty microbes from taking up residence in the humidifier. This helps prevent allergies and a range of potential respiratory problems. Filters are usually made of either paper, metal or metal coated with clay. In most cases, the filter should be changed approximately every 3 months, dependent of course on how often you use the humidifier. If the idea of buying and replacing wick filters doesn’t interest you check out one of the ultrasonic humidifiers profiled above.

Automatic Shut Off - The last thing you want is for your humidifier to run dry in the middle of the night. Not only will you wake up with the desert mouth, dry eyes and perhaps a headache from the dry air but if the humidifier continues to run with an empty tank there exists a fire risk. If you purchase a humidifier with a large tank (say 1.5 gallons+) and fill it before you go to sleep you should be fine. However, if you have a smaller humidifier and you forget to fill it right before you hit the sack there’s a chance it might run dry in the middle of the night. As such, auto shut off feature is a must on these types of small room humidifiers.

Humidistat  - The humidistat is nothing more than a gauge that measures the humidity in the air. Some humidifiers have them and some don’t. They can be useful in helping you find the right setting for your humidifier. If the humidistat shows that the air is exceptionally dry you simply crank up the humidifier a bit. If the humidistat shows that the air is already fairly damp you may want to forego using the humidifier for the time being. Without the humidistat, you are essentially flying blind and guessing whether or not the air is dry enough to warrant using the humidifier. Keep in mind that even if the unit you have your eyes on doesn’t have a built-in humidistat they are pretty easy to obtain either online or at many home improvement centers.