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.