Operating time
It is the operating time of the humidifier with a full tank. It depends on the volume of the tank and on the water consumption (see below for both). For models with humidity control (see "Features"), this parameter can be indicated in different ways: in some cases, the maximum duration of the operation is given (at the minimum output humidity), and in others — vice versa. Nevertheless, according to the declared figures, it is quite possible to estimate the operating time at least approximately.
Water tank volume
The volume of the water tank installed in the humidifier. Large capacity allows you to work longer without refuelling but affects the dimensions and weight of the device. Therefore, manufacturers choose the volume based on a compromise between these points and taking into account water consumption. Usually, the volume of the tank is chosen in such a way that the humidifier can work quietly on a single refill for at least 2-3 hours, and often even more. Accordingly, the more capacious the tank, the more powerful and performant the device, as a rule. So, models with a volume
of up to 2 litres belong to the entry-level,
from 2 to 4 litres — to the average,
from 4 to 6 litres — to the larger than average category, and in the most capacious devices this figure can
exceed 6 litres .
Note that for models with the possibility of using a bottle (see below), this paragraph often indicates the optimal capacity of the bottle (such devices may not have their tanks).
Min. noise level
The noise level generated by the air cleaner when operating in low or night mode. Most of these devices are used in domestic conditions, so the noise level plays an important role, especially at night. According to sanitary standards, constant noise in such rooms should not exceed 40 dB (quiet conversation) during the day and 30 dB (wall clock ticking) at night. More detailed comparison tables and recommendations can be found in special sources.
Power consumption
It is the maximum power consumed by the device during operation. The lower it is the more economical the device. However, it is worth noting that in humidifiers, energy consumption is directly related to the principle of operation (see "Humidiation"): with similar characteristics, steam models are high consumption, where energy is spent on heating water, and the most economical are water models. Nevertheless, the energy consumption of modern humidifiers is generally low — even for steam humidifiers it rarely exceeds 600 W, and ultrasonic devices with similar power are already heavy industrial equipment. Purifiers also do not differ in consumption: a power of more than 100 W is rare among such devices.
