Which HVAC Filter Is Right for You?

Our HVAC Professionals Can Help You Choose

HVAC filters are a big part of keeping your indoor air clean and extending the life of your HVAC system. At Timothy Off, we suggest changing/cleaning your HVAC filter every 1-3 months, depending on the type of filter you use, the season, and whether or not you have pets. If you just got a new HVAC system or you haven’t changed your filter yet, you may not be sure which type to buy. Our Coatesville heating and cooling company can help:

Filter MERV Numbers

Each filter has a Minimum Efficiency Reporting Value (MERV) number that ranges from 1 to 20. The number tells you what kinds of contaminants the filter controls (in other words, how effective it is). The lower the MERV number on your filter, the lower quality the filter. Most HVAC units in residential homes us 5-8 filters that control mold, mildew, pet dander, and dust. However, if your family has trouble with allergies and/or asthma, you may want to consider getting a higher number filter, such as a 10-12.

Filter Sizes

Each HVAC filter has two different sizes – a nominal size and an actual size. The nominal size is a round number that refers to the filter’s approximate size rounded up to the nearest inch, while the actual size gives you the actual dimensions of the filter. You want a filter that will fit your HVAC system correctly, so before you buy one, consult your owner’s manual.

Filter Types


Pleated filters are the most popular HVAC filter. They are thin and have a large surface area that can effectively trap contaminants, removing up to 45% of the pollutants in your home. MERV rating: 8-13.


Fiberglass filters are thin, inexpensive, and are good for keeping equipment clean, but don’t filter much. They can collect large particles like lint and dust, but aren’t able to capture smaller particles like mold and bacteria as well. MERV rating: 1-4.


Washable filters are great because you don’t have to replace them as often. However, they can collect bacteria and mold if you don’t dry them properly. Otherwise, they’re good for trapping larger contaminants like lint and dust, but not much more. MERV rating: 1-4.



Today’s high-efficiency filters can remove up to 85% of contaminants and are highly recommended for any HVAC system. MERV rating: 14-16.

Not sure which HVAC filter is right for your system? Give our Coatesville heating and cooling experts a call today for more information.


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