Humidifier 101: what & how

Generally, how many kinds of humidifiers there are?

There are many humidifiers on the market, and most of them can be categorized into two: ultrasonic humidifier, and evaporative humidifier.

How does humidifier work, actually?

Ultrasonic humidifier: this type of humidifier generates high-frequency vibration to diaphragm(or other type of vibrating elements), vaporizing the water into mist to achieve humidification. At 1.7MHz, the sound of working vibration frequency is beyond a human's hearing range to be inaudible. Significantly, when an ultrasonic humidifier is working, white mist comes from its grill(or nozzle). The concentration of mist depends on its working modes.

Evaporative humidifier: this type of humidifier inhales the dry air with built-in motor, then accelerates the air through vaporizing pad with water membrane or vaporizing filter to bring the water droplets outside its body for humidification. The water droplets coming out of an evaporative humidifier are much smaller in size(close to natural evaporation droplets' size) than that coming from an ultrasonic humidifier, making them much easier to distribute evenly into the air. That is also why evaporative humidifier doesn't produce white mist when working.

Which one performs better?

From the last question, we learned that there is a significant size difference in water droplets coming out of both types of humidifier. Ultrasonic humidifiers produce bigger water droplets, which would easily form white mist in the air. However, bigger water droplets would also fall faster, reducing their sprinkle area, hence slowing down the humidification throughout the space. Another issue is that bigger water droplets also carry more substance from the water source, including impurities(like calcium or magnesium). When the mist spreads, the impurities are also carried to the air. This also explains why some users of ultrasonic humidifiers would see white residue on their furniture or floor.

With different working mechanics, evaporative humidification produces much smaller water droplets, bringing nothing but humidity back to air, achieving healthier & more effective humidification.

White mist means the humidifier is working, is that true?

Ultrasonic humidifiers generate white mist when working, while evaporative humidifiers tend to keep the humidification invisible.

Why does the air purifier indicator turn red when I open my ultrasonic humidifier?

This usually happens when you are using ultrasonic humidifier along with your air purifier at a close distance. The humidifier releases water droplets at the same size as solid pollutant particles, which would be recognized as air pollutants by the particle sensor of air purifier. With evaporative humidifier, however, the sizing of water droplets is much smaller, and it works with air purifier with no problem.

How would I know the humidifier was working if nothing is in the air?

Most evaporative humidifiers were equipped with environment sensors to monitor real-time humidity and temperature. Take smartmi evaporative humidifier for example, you can read the realtime air humidity through LED display, or on smartmi link APP.

Evaporative humidifier doesn't need maintenance, right?

As convenient as evaporative humidifier sounds, its working condition still relies on the water quality of where you live. In many regions where drinking water contains minerals like calcium or magnesium, white residue is still possible to gather on the surface of water tank inside the humidifier after long-term use. We recommend adding some citric acid detergent and open self-cleaning mode(available on smartmi evaporative humidifier) for 30 mins or handwash until the filter(or evaporating pad) is clean.

If the water tank or evaporating filter smells bad, that means bacteria breeding in the water, it's best to wash the compartments with washer thoroughly and expose them under the sun for complete drying.