How To Navigate HVAC Air Filters Efficiency Ratings

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A quick Amazon search under the air conditioner filter category brings up over 800 results! It's all too easy to take the easy road and purchase the cheapest filter, especially when prices range so greatly. But as everything else, buyer beware: the effectiveness of HVAC filters ability to remove airborne contaminants such as pet dander, dust mites, smoke, and mold usually correlates with the price. Here are some informative rating resources for buyers to refer to before replacing or upgrading their home's air filtration system...

The fact is not all air filters are created equal. The cheapest filters might be fine for filtering out large sized household dust and lint, but the typical home's interior air is polluted with a lot more unwanted elements composed of much very fine size. The EPA provides an informative breakdown of particulate matter and gaseous pollutants often found indoors, listing the "two categories of indoor air pollutants that can affect the quality of air in a home." Viruses, bacteria, pollen, mold, dust mite, animal dander, smoke...nobody wants to breathe these inside their own home and the cheapest of HVAC filters do a poor job of removing these elements from interior air.

So what should a buyer look for when shopping for an air filter effective against a wide variety of particulates and pollutants? Fortunately, there are ratings systems to help compare the level of protection air filters provide. Unfortunately, many groups, stores, and manufactures tout their own rating systems, which means choosing the right HVAC air filter takes a little cross-referencing and research.

The American Society of Heating, Refigeration and Air-Conditioning Engineers (ASHRAE) designed a rating system known as Minimum Efficiency Reporting Value (MERV). MERV ratings run from 1-20, designating the effectiveness of filers to capture smaller and smaller minimum particle sizes. The higher the MERV rating, the better, and we recommend this rating system the best for determining filter efficiency.

Big brand, Filtrete, uses their own Microparticle Performance Rating (MPR), rating their filters based upon air filtration efficacy. Their basic system simply groups filters into "good (300 MPR)", "better (600 MPR)", and "best (1,000 MPR)" - with "best" capturing "at least 90% of large particles from the air passing through the filter." Their MPR rating is unfortunately only useful if purchasing their brand of air filters.





The Home Depot's Air Filter Performance Rating (FPR) System below aims to make it even easier to compare brands by presenting a unified ranking system in an easy-to-read chart/rating based upon the filters' 1) ability to capture large particles, 2) ability to capture small particles, 3) and weight gain (filter lifetime). But the FPR rating system lacks specific figures for the sake of simplicity.

New Filter Ratings Chart from The Home Depot

As Chris Gardner over at BobVila.com points out, buyers should skip over the most affordable and common fiberglass spun filters, with a paltry MERV rating of 2-3. For just a few dollars more, disposable pleated models bump up the MERV rating to 6, while disposable electrostatic cotton or paper fiber filters rate at 10 and are probably the best option for those balancing budget vs. performance. Those with deep pockets and bad allergies can invest in a deep hi-efficiency pleated filter with a 14-16 MERV rating matched with a $100 price tag. Or better yet, purchase one of these hospital grade units for every room.

While the rating of an air filter is important for air quality upkeep, there are many preventative steps that can be made to improve the air inside even before turning on the HVAC system. Frequent house cleaning, avoiding smoking indoors, and keeping a small indoor garden of plants are all effective ways to improve air quality inside. Now if only we can try to remember to replace our filters now and again!

MORE AIR FILTERS ON APARTMENT THERAPY


(Images: Home Depot, Shutterstock/Serenethos)