People spend a lot of time dialing in the perfect temperature for their homes, but few worry about their home's humidity levels. While people associate humidity with feeling hot and sticky in the summer, indoor humidity is important to your health. Maintaining ideal indoor humidity is a difficult task with the seasonal changes throughout the year. In the summer, your air conditioner will capture and condense air from your indoor air on condenser coils, and in winter cold air infiltrating into your home won’t hold on to water molecules as effectively. The Environmental Protection Agency advises that the ideal humidity levels are between 30 percent and 50 percent, so if you feel uncomfortably dry inside, then an in-room humidifier could help you out.
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What to Look for in a Humidifier
Size, Capacity and Features
There are lots of factors you'll want to consider when buying a humidifier, most importantly: how often will you be using it and for what purpose? Whether you're looking for a machine to humidify a large room or a smaller version for your desk at work, the capacity, runtime and square footage will tell you everything you need to know. Most humidifiers on this list hold around a gallon of water in their water tank and runtimes range from 6 to 70 hours. If you're looking for a machine that you can leave on all day every day with minimal refills, then you'll want the one with a higher runtime and capacity most likely. But if you're just looking for a humidifier to get you through the night, a smaller capacity and runtime may be okay, especially if it means a lower price point. The square footage a certain model is able to cover will also tell you if it will work in the space you have in mind because, like air purifiers, humidifiers work best in small, enclosed spaces.
Whole-house humidifiers cost thousands of dollars and require complex installs, so small units are a better investment to improve the moisture in an individual room when you actually need it. We found humidifier models covering 300–1,000 square feet to be a good balance for bedrooms to larger living rooms. While water tank size is important to determine runtime, we found humidifiers that at least offered 8 hours of runtime to be the least disruptive.
In our testing, the most important feature of a humidifier was a humidistat — basically a thermostat but for humidity — that monitored the active humidity. When left untouched, cheaper humidifier models with simple on-and-off control often raised the humidity far above the 60% maximum recommendation, leading to condensation on interior windows and surfaces in the room.
Types of Humidifiers
While they serve the same purpose, the main difference between the three types of humidifiers — evaporative, ultrasonic and hot air — is how the machines create their humidifying mist. Ultrasonic humidifiers, also known as “cool mist” humidifiers, use a piezoelectric disc that vibrates at a high-frequency signal to create micron-sized water droplets that are then slowly absorbed into the air. Evaporative humidifiers won’t actually generate any visible moisture because it’s simply a fan blowing over a wet membrane to evaporate the water into the air. (Whole-house or console humidifiers are typically evaporative.) Lastly, warm mist humidifiers heat a water reservoir to create steam which is then quickly absorbed by the air.
In practice, all of these humidifiers will raise the indoor humidity but we found cool mist humidifiers to be the best option on the market. In our testing, cool mist humidifiers were far less energy demanding than warm mist (avg. 40 watts cool vs 260 watts warm), and considerably easier to clean.
Benefits of Using a Humidifier
There are myriad benefits to using a humidifier, from helping to ease congestion to combatting the dry winter air throughout the night. But you don't want to treat your humidifier as a cure-all and overdo it. According to a 2012 study, too much humidity can actually disrupt your sleep cycle.
And if you're not cleaning your humidifier regularly, then its benefits will quickly go away as your machine could be growing mold or bacteria. You should be cleaning your humidifier every three days, according to the Environmental Protection Agency. And you can do so by scrubbing the parts with vinegar and rinsing with water. Furthermore using bottled or distilled water will help to prevent build-up in your humidifier.
You may think the best humidifier for you comes down to personal preference, but there are a lot of different uses for these machines. From humidifying your plants to helping you sleep at night, we set out to find the best humidifiers, considering factors like available settings, noise level, ease of cleaning, water capacity and room coverage. Our testers have been using their humidifiers for several months to become experts in their machine's benefits and drawbacks, especially when it comes to upkeep. So if you're starting at square one and all humidifiers look the same to you, then you've come to the right place.