In addition to the method of air humidification, the important criteria is the area of the room for which the device is designed, the volume of the tank and the water consumption (small unit can work with 1.5-liter water tank for 16 hours, residential units use from 2 to 12 gallons per day).
The tank size and water consumption of the room unit defines time without refilling. The humidifier should work for at least 10-12 hours. As a rule, a tank of water of 6-7 liters is enough for 24 hours, 3.5-4 liters – for 12 hours.
- The low-level water indicator. It is much easier to note the LED light than to check the water level by eye, especially when the tank is not transparent.
- Automatically turn off function when the unit runs out of water. You can forget to pour water, the device can be accidentally touched and knocked over by a child or pet – all this should be safe for the home, child, cat or dog.
- Indicator for cleaning the device.
- Not a function, but it is important. The tank or whole unit should be easy to carry, there must be a handle.
- It is great, if humidifier is able to rotate around its axis and spread steam in different directions.
- Night mode. It is especially important for devices with natural humidification, with noisy fan, and for devices with bright light indicators and displays.
Air cleaning. If filters are installed in the humidifier, the manufacturer usually declares this function. If the unit comes with antibacterial filters – declares loudly. But the humidifier is not an air cleaner, and cleaning action can only be a secondary feature. If you have serious problems with health – allergies, asthma, you need to control the humidity of the air. Air filters will clean air much more effective. Besides, filters need to be changed, and it is additional expense item.
Traditional evaporative humidifiers are an exception. Filters there are an obligatory part of the design, and if they are antibacterial, it is even better.
Aromatization of air. Usually, the flavor is poured into a special capsule through which air is taken. Using flavors (as a rule, they are oil based) is not necessary and most of devices have not such feature.
Ionization. The enrichment of air by negatively charged particles have the property of attracting and retaining moisture, contributes to better air humidification.
Water lighting. Such humidifier can also work as a night lamp.