3M has been selling air conditioner (AC) filters that can be added to the inlet of ACs for some time now. 3M markets them as being simple and easy to attach, and a great way to reduce PM2.5 in homes without an air purifier. But do they actually work? How effective are 3M air-con filters at cleaning the air? We’ll find out 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 that 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.
Effectiveness of 3M AC Filters at Cleaning Indoor Air
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 performed a series of tests on the 3M filters.
After attaching the 3M filters to the air conditioner in a 20sqm room, we measured PM2.5 before and after the air conditioner was turned on high.
Results showed a large decrease in PM2.5 after the air-conditioner with 3M filter attached was turned on. After one hour of running the air-conditioner, PM2.5 reduced 87.9% from 33 μm/m³ to 4 μm/m³.
More specifically, after one hour of running the air-conditioner, PM2.5 concentration reduced 87.9% from 33 μm/m³ to 4 μm/m³. This is safely below WHO recommended levels of PM2.5 of 10 μm/m³.
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 20sqm 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.