Air washers use water for air purification.  It is an efficient method of removing pollutants, hair, pollen, dust, and even bacteria from the air.  These devices make use of rollers that pass the air through a water bath, through which the contaminant particles are removed.  The process also evaporates part of the water, increasing the level of humidity in the air.

Is an air washer the combination of an air purifier and a humidifier?  What are the advantages of an air washer

How do air washers work?  What is the difference between an air purifier, an air washer, and a humidifier? Is it true that air washers do not need filter changes? This guide will answer these questions and give you tips on how to choose the right air washer.

Air Washer Explained: Technology and Function

An air washer mainly mimics the cleaning effect of rain in purifying the air with the use of water.  Similarly, the air washer process also increases the level of humidity.  Instead of using rain drops, the device uses a film of water, which enables the operation to be continuous and more effective.

How Does an Air Washer Work?

The air washer technology works by sucking the air in the room through fans and nozzles and passing it on to rotating disks, partially filled with water.  The captured dry air absorbs moisture.  Dust particles are removed from the captured air.  They stick to the wet panes and get washed out through the rotation of water.  The device releases the clean air.

Moreover, the released air is moisturized.  So, the humidity level increases.  Humid air reduces the rate of spread of germs.  Water molecules can also interact with suspended particles in the air, leading them to be heavier and to fall down on the surface.  This way, increased humidity also helps clean the air indoors.

What Is an Air Washer Good For?

Air washers can only remove larger particles from the air.  An air washer can effectively remove 90% of particles larger than 10 µm in diameter.  However, this rate falls below 20% when it comes to particles smaller than 1 µm in diameter.

This makes air washers practical to use against hair, pollen, and dust.  Some bacteria, typically sized between 1-10 µm in diameter, can also be removed by air washers.  Though smaller air particles such as fine dust, molecular odors, pollutants, and viruses cannot be filtered out through the use of these devices alone.

Differences Between an Air Washer and an Air Purifier

Air washers are a 2-in-1 appliance, meaning they serve two functions at the same time.  Unlike an air purifier, an air washer does not only clean the air, but it also humidifies the air.  Thus, an air washer combines the function of an air purifier and a humidifier in one device.

Particle Filtering With Air Washers

Most of the modern air purifiers are equipped with highly effective particle absorbing (HEPA) filters.  The finely woven fiber filter mats effectively remove even the smallest particles down to 0.1 µm in diameter size. HEPA filters are designed to remove 99.97% of particles larger than 0.3 µm in diameter, passing through them.  Accordingly, HEPA air purifiers are significantly more effective than air washers in cleaning the air.

The cleaning technology of air washers are completely based on a physical process.  The dust particles stick to the water and thus are filtered out of the air.  This physical effect is much weaker for smaller molecules, such as odor molecules or those in volatile organic compounds found in solvents.  There are other air purifier types that use chemical processes to remove these other molecules.  Some examples include ultra-violet filters, photocatalysts, and ionizers.  These let highly reactive gases or radiation to break down the airborne pollutants.

What Distinguishes Air Washers from Basic Humidifiers?

Air washers purify the air with the use of water.  Inside the device, part of the water evaporates. This results in the extracted air to have a higher humidity level than when it first entered.  Evaporation in air washers take place at room temperature, significantly below the boiling point of water.  This is why no water vapor is generated in the process.  Thus, the humidification effect of air washers is limited. 

Humidifiers on the other hand, actively make use of the evaporation process.  These devices bring water to the boiling point.  Hence, not only moist air, but water vapor is extracted from humidifiers.  Humidifiers can cause over-humidification of the air.  This may lead to excess water droplets to deposit on walls, windows, and other surfaces.

Contrary to humidifiers, air washers cannot get rid of all germs.  The filter effect gets rid of some bacteria, however the remaining air is by no means completely sterile.  Having said that, air washers are robust devices.  They can be operated with water of all quality levels from hard water to soft water.

Advantages and Disadvantages of an Air Washer

The main advantage of an air washer is that it combines two functions in one device: air purification and humidification.  If you have to deal with dust and dry air at the same time, an air washer can offer a solution for both issues.

If you suffer from respiratory infections and mucous membrane irritation, air washers are particularly effective.  While the cleaning function decreases the likelihood of infections, the humid air can help reduce the irritation symptoms in your throat and your nose.

Air washers are ideal for multiple applications.  They are robust humidifiers and air filters.  Air washers are easy to care for, as no filter change is required.  Regular cleaning of the device is sufficient. 

As for disadvantages, air washers are average in terms of air purification.  Many types of other air purifiers are more effective at reducing the number of pollutants and dust in the air.  HEPA filters and activated carbon filters are among examples that lead to a higher purity level in the air, when compared with air washers.

Overall, it is fair to state that an air washer is more of a humidifier with an air cleaning function than an air cleaner with a humidification function.

Air Washer Maintenance

Air washers do not require any filter or part changes.  This makes these devices much cheaper to operate, when compared with other air purifiers.  They do nevertheless require a lot of attention and maintenance to ensure hygiene.  If not cleaned properly, water can serve as an ideal breeding ground for germs.

Do Air Washer Filters Need to be Changed?

No.  Air washers do not have filters, hence no filters to be replaced.  This is an advantage in operating cost over other types of air purifiers like HEPA and activated carbon filters.  

Nevertheless, the time required to clean and maintain air washers can typically be longer than those of other air purifiers.  Air washers should be cleaned on a monthly basis in order to ensure proper functioning.  If the air washer is combined with another type of air cleaner, there may be additional filters that need to be replaced regularly.

Air Washer Hygiene

It is of utmost importance to clean an air washer on a monthly basis.  The water should be replaced much more frequently, depending on operation time and tank size.  

All parts of the device that interact with water must be cleaned thoroughly every month.  Otherwise, algae, bacterid, and mold can breed in and around it.  Better air washers typically have removable and dishwasher-safe partitions.  They can be easier to clean. 

In order to ensure germs do not settle and breed within the device, it is recommended to add disinfectant to the water in the tank.  Make sure that the disinfectant does not have hazardous chemicals and also that the device allows for the usage of disinfectants.

In case proper cleaning is not performed and germs settle in the device, this can defeat the whole purpose of cleaning the air.  The released air would then include toxic moisture, polluting your home and irritating your respiratory system.