REDMOND RAW-3501 air washer

Air washers combine the functions of air cleaner and humidifier and work on the principle of natural not ultrasonic humidification. How effective they are? Do they have system disadvantages and, conversely, undeniable advantages? Is it easy to use?? Let’s test it on a compact model of a well-known manufacturer – the REDMOND RAW-3501 air washer.


Working principle

The device consists of two units: a lower one with a water tank and an integrated rotating drum with special discs, and a higher one with an electronic control unit, fan and air outlets.

The fan forces the air together with the dust contained in it into the body of the sink, there the dust settles on the filters of the drum, washed off with water and is retained in the reservoir. Moisture evaporates from the purified disc surface, humidifying the air. No complicated and high-tech air filters are not provided in this class of devices: everything is as simple as possible.

Controls and functions

The control panel is on the top, it’s really convenient if you put the device on the floor or, as in our case, on the chest of drawers.

Buttons are touch-sensitive and back-lit, a light touch is enough to turn the sink on or off, activate the ionization function anion button , night mode sleep , turn off or on the circular panel light bulb , set the off timer from 1 to 8 hours in 1 hour increments , select one of the three fan speeds low, medium, high – all in English . It should be noted that the noise level naturally increases with the speed of the fan measurements below .

If you do not select fan mode, the wash cycle is in automatic mode, which is indicated by an indicator light.

Auto mode is medium speed without ionization.

There is a no water light on the control panel: if the washer is switched on but no water is poured, it flashes and the appliance does not work. There is also a lock for the control panel: so that it becomes inactive and the settings are not confused if a child or pet accidentally touches the panel. To activate the lock, you must press the timer and backlight buttons together and hold them for three seconds to unlock, you must do the same.

Climate control equipment

Sleep mode

It should be mentioned separately: in fact the air washer is often bought for children or for people sensitive to allergens, who need the device to work all the time. In sleep mode, the backlight is turned off only the power button and the light indicator of this mode are lit, but it is almost imperceptible and not annoying . The fan runs at lowest speed and is almost silent.

Evaluating efficiency and ease of operation

Humidification and air purification

We did this test in summer, when the heating was off, and the baseline humidity was quite high: 72% according to the mechanical hygrometer. The humidity rose to 75-76% in a day of operation, and the week of operation varied within these limits.

In principle, any air washer acts more like a humidifier with the principle of natural humidification.

The air-cleaning function of the washers does not work as well as in air purifiers that run the air through HEPA filters. The only filter here is water, its ability to clean the air from dust is not great, but in humidified air the dust particles become heavier and quickly settle instead of flying around, which makes breathing easier for people sensitive to dust.

Our verdict: it cleans, but not very well, and the humidification is good. But in winter, with heating, it would probably feel better. Humidifiers with natural humidification has a feature: they do not saturate the air with moisture, which is also important: mold is excluded.

Noise level

The machine is almost noiseless in night mode and at low speed. Manufacturer claims noise level of less than 25dB but does not indicate maximum or minimum. According to our observations and measurements – minimum. At the highest fan speed the noise level was 34dB, which is also rather quiet, by the way – the operation of the washer will not be a distraction.


The sink is nice and easy to operate, and we have only two comments on usability. First, it would be nice if the previous mode selected would be remembered when the unit goes to sleep mode e.g., when the water runs out or the sleep mode is turned off. Not at all: You have to reselect all settings. The second one is the English signs on the control panel. Yes, all duplicated “icons” with icons, but still, the device with the English control panel may not be convenient for all American-speaking users. Usage of the cleaner is otherwise pleasant and comfortable, the sensors are “responsive”, the backlighting is beautiful, functions are simple to understand and care is uncomplicated.

Flow and refill of water

The principle of the humidifier is not ultrasonic, but natural – the water simply evaporates, and since there is no heating, it evaporates slowly. The water consumption of the air washer is really very economical.

The manufacturer writes that the water consumption is 150 ml/h, but we did not notice such a waste: considering that the volume of the tank is 2.2 liters, it should take less than a day for complete evaporation, but this did not happen even at maximum fan speed.

We refilled the water every two days – the temperature in the house at this time ranged from 19-20 degrees at night to 24 during the day the manufacturer does not write at what “weather” the device consumes 150 ml/h . It is not possible to add water to the sink while it is running: it is necessary to remove the upper part and fill the lower one. Drain the rest of the water is simple: the bottom is small and light, you only need to pull out the drum with discs.

Hardware for home


Besides the need to change the water and wash the tank, you need to periodically clean the drum, but in the few weeks of use we have had very little soiling.

The drum can be dismantled into discs and cleaned individually: It’s easy to unscrew the nut holding them in place and a special cleaning brush is included.


Surface area: up to 20m².

Power output 15 watts.

Control: touch control.

Functions: cleaning, humidifying, ionization of the air.

Warranty: 1 year.

Service life: 3 years.

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