3M has been selling air conditioner (AC) filters designed to be added to AC inlets for quite some time. These filters are promoted by 3M as a simple and easily attachable solution—a great way to diminish PM2.5 levels in homes without the need for a separate air purifier. But the real question is, do they live up to their claims? How effective are these 3M aircon filters at purifying the air? Let’s delve into the details in this article.
How 3M Air Conditioning Filters Work
Filtering out pollution from the air is incredibly simple. A fan and a filter are all you need, and you can even DIY one yourself.
An air conditioner is a fan that blows out cold air. So the idea behind the 3M air conditioning filters is that by sticking them onto the inlet of the aircon unit, the aircon will provide clean, cold air out.
Are 3M Filtrete Air Conditioner Filters HEPA Filters?
No, 3M Filtrete air conditioner filters are not HEPA filters. They are a lower grade media filter. The box does not say what filter grade they are but describes the filter as a “electrostatic charged synthetic fiber.”
Do 3M Aircon Filters Work?
3M claims the filters they sell can capture particles as small as 0.02 microns and can remove 83% of PM2.5 in one hour. But they don’t give any information on how this is tested. How big was the room? What speed was the air-con set at? To answer these questions, we tested the 3M filters.
After attaching the 3M filters to the air conditioner in a 20 sqm room, we measured PM2.5 before and after the air conditioner was turned on high.
Results – 3M Aircon Filter Significantly Reduces PM2.5
Results showed a large decrease in PM2.5 after the air conditioner with the 3M filter attached was turned on. After one hour of running the air-conditioner, PM2.5 fell 87.9% from 33 μm/m³ to 4 μm/m³.
This is below the WHO annual PM2.5 limit of 5 μm/m³. However, in a more polluted room, the numbers will likely not go so low.
Does the Air Conditioning Function Still Work with 3M Filters Attached?
Attaching 3M filters to an air conditioning unit will increase the air resistance, and mean that the aircon unit needs to work harder. In our tests, we found that the amount of air coming out of the aircon unit was reduced by 22% after attaching the 3M filters.
Despite this, the air conditioner was still able to cool the 20 sqm room down to a temperature of 20ºC. It’s worth noting, however, that the increase in air resistance may cause wear and tear on the AC’s motor, reducing its lifespan. If you plan on installing these 3M filters on your own AC unit, make sure not to cover the entire AC filter area. Leaving gaps around the edge will reduce filtration effectiveness, but also help reduce work on the motor.
The Best Way to Clean Your Air
Although 3M filters can help improve your air quality, HEPA air purifiers are the most effective way to remove cancer-causing PM2.5, allergens, and viruses from your air.
At home, I use the Smart Air Sqair HEPA air purifier.
Smart Air is a certified B Corp committed to combating the myths big companies use to inflate the price of clean air.
For a fraction of the cost, Smart Air provides empirically backed, no-nonsense purifiers and masks, that remove the same particles as the big companies. Only corporations benefit when clean air is a luxury.
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“It’s worth noting, however, that the increase in air resistance may cause wear and tear on the AC’s motor, reducing its lifespan.” doesn’t make sense! The centrifugal fan will do a bit LESS work with the reduced airflow, and draw less current.
The lowered airflow will have the same effect as a lower fan speed – less air through the evaporator coil. I suppose if a low fan speed along with a clogged filter may freeze up the evaporator.
I never found a peer review paper showing that 3M Filterete filters have been shown having a sustained efficiency in removing particulates. This triggers an alarm that well controlled experiments may have never
demonstrated efficiency.
I did a similar experiment to assess the efficiency of 3M filter attached to an air conditioner. It did decrease by a half the PM2.5 concentration measured by two independent devices for a few hours. This apparent effect was not sustained after 8 hours.
Adding filters to you AC is not a great idea – like others mentioned you degrade the performance. The fan in your AC is designed to have HUGE airflow but only at really small pressure. If you add ANYTHING to its path, you will decrease the airflow quite a lot. This will not only reduce the performance but also degrade efficiency as the coolant leaving the indoor unit for the compressor is still pretty cool as it didn’t have enough airflow to heat up more.
With these filters fitted the airflow is reduced, therefore the system temperatures/pressures are affected, which will reduce the efficiency and running costs