Do Air Conditioners Clean and Purify for Good Air Quality?


People are asking if their air conditioners clean air? So, I decided to answer that with both home and commercial air conditioners.

Air conditioners do clean air. Typical home air conditioners filter air by channeling the air through plastic mesh filters. Premium home air conditioners perform better with PM2.5 filters. Commercial air conditioners use pocket filters and HEPA filters to remove finer particles such as smoke and bacteria.

Air conditioners play an important role in public health by maintaining decent indoor air quality. Let's look at some of the types of air conditioners and their filters used in both home and commercial buildings.

How Air Conditioners Clean Air?

The air conditioner clean air by using its built-in filters. These filters block various sizes of particles. The higher the filter class, the higher the efficiency of the filter and thus, the finer the particles it can block.

The filter class for typical home air conditioners such as window and wall-mounted type is either G3 or G4. These filters can remove particulate matter sized more than 10 µm such as small insects, hair, pollen, and dust. They are not capable of filtering smokes, fumes, bacteria, and viruses. They are typically a mesh type filter that made of plastic and they are often washable.

Plastic mesh filters of the wall-mounted air conditioner in my bedroom.

However, some high-end wall-mounted type air conditioners have a better filter such as the PM2.5 filter. PM2.5 filter is capable of removing fine particulate matter sized 2.5 µm or smaller such as fumes and smokes. This is particularly effective when dealing with haze.

Daikin Malaysia SMARTO wall-mounted inverter type air conditioner.

Some large houses use a different type of air conditioner such as the ceiling ducted fan coil unit. The filters for these types of air conditioners usually are classified as either F7 or F8 or F9. These filter classes are better than G3 and G4 because they can remove particulate matter sized from 1 to 10 µm.

On top of blocking small insects, hair, pollen, and duct, they are also capable of filtering fumes and smokes but, not bacteria and viruses yet. Ceiling ducted fan coil units also commonly used in commercial buildings such as offices, hotels, manufacturing plants, hospitals, and halls. These commercial buildings often have an in-house maintenance team that regularly wash the filters of their air conditioners.

The filter of a fan coil unit in a hall.

Then, it comes to the high-end filters used in laboratories, semiconductor plants, pharmaceuticals, food processing plants, clean rooms, hospital isolation rooms, and nuclear plants. These filters often are used as the final air filtration for rooms with the highest purity requirements. These filters are known as the HEPA filter or high-efficiency particulate air filter which can remove particulate matter sized less than 1 µm.

Based on European Standard, at least 99.95% of particles whose diameter is equal to 0.3 µm can be removed from the air that passes through a HEPA filter. The HEPA filter is capable of removing bacteria, viruses, and aerosols.

An air conditioner with HEPA filter is superb in achieving clean air but HEPA filters are much more expensive and HEPA filter is not washable (must replace a new one when dirty). Thus, almost all air conditioners with HEPA filters will usually have an F7 or F8 or F9 classes pre-filter that blocks the bigger particles so that the HEPA filters only need to take care of the smaller particles. Hence, prolong the lifespan of the HEPA filter.

Do Home Air Conditioners Need High-Grade Filters?

Typical home air conditioners only remove dust in the air and it is often good enough. The purpose of the filters in a wall-mounted type air conditioner not only clean air but also protects the cooling coil from clogging. Cleaning the cooling coil is much harder than washing the filter.

In my article titled do air conditioners take in fresh air from outside where I mentioned that people who are staying at home open the doors and windows all the time. Typical houses are well ventilated by the nature airflow. Thus, it is unlikely to grow germs, bacteria, or viruses inside the spaces.

Therefore, it is not necessary to have higher grade filters for home use air conditioners. Nevertheless, if you have an allergy, you may need a better indoor air quality that could ease your condition. Perhaps, an air conditioner with a PM2.5 filter.

How Often Should You Clean the Air Conditioner Filter?

I'll check the plastic mesh filter of my air conditioner once every 2-3 months. If it is dirty, I'll just wash it. It is not a must to wash at a fixed interval. However, if you have not washed your air conditioner filter for more than 3 months, it's time to check it out.

A dirty filter will reduce the performance of your air conditioners and your air conditioners will also consume more power. For a PM2.5 filter, I suggest you should check its condition every month because they are finer and gets dirty quicker than the plastic mesh filter.

For commercial buildings, they have tons of air conditioners and the filter condition of each air conditioner is different. Hence, it is best for them to set an interval like once a month, to wash all the filters.

How about Air Conditioners with Ionizer?

An air conditioner with an ionizer can produce negative ions that claimed to remove bacteria and odor. In fact, they did not remove bacteria and odor. Instead, negative ions make the bacteria and odor particles stick to the wall, floor, and bed.

Smartairfilters.com published an article on ionizers and it turns out that most ionizers have little to no impact on the cleanliness of the air. Moreover, more negative ion doesn't mean it is good, and in fact, it causes more harm due to the production of ozone.

Remember that negative ions make those bacteria fall down and stick onto your bed which is doing no good at all. Hence, they concluded that ionizers are unnecessary because a HEPA filter does a better job in filtering particulate matters and thus, delivering cleaner air.

Related Questions

Do air conditioners filter smoke? Typical home air conditioners are not capable of filtering smoke. But, commercial air conditioners such as fan coil units and air handling units often equipped with F7 or higher class filters which are capable of filtering smoke.

It is an air purifier the same as an air conditioner? No. The main purpose of an air purifier is to filter harmful particles, usually with a HEPA filter. The main objective of an air conditioner is to provide cooling and reduce the relative humidity in the process.


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Yu Chang Zhen

I enjoy working on air conditioners and ventilation fans because Malaysia is a very hot country.

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