Are all HVAC air filters the same?

No, HVAC air filters vary in quality and size, and some have specs that others don't. Usually we recommend using the filter your HVAC manufacturer recommends pairing up with your installed system, however you might be tempted to try a different filter type for convenience or to remove more pollutants from the air.

Filters have MERV ratings, which range from 1-20. MERV is an acronym for "minimum efficiency reporting value". A higher MERV rating tells you that fewer contaiminants pass through, and it blocks finer particulates. This seems obviously good, and it can be, but a filter that stops finer dust and allergens will also build up quicker, and pressure on your unit will go up. If your system has not been crafted to operate with this kind of filter, it can actually reduce your airflow within your house, impacting your comfort and energy expenses. So what should you do? Unless you're a hospital, you simply don't need a MERV rating above 13. Fun fact, most residential systems are specifically designed to work with a filter with a MERV rating below 13, and frequently you will learn that quality systems have been made to function with a MERV rating of 8 or 11. All filters with a MERV rating of at least five should block most of the everyday nuisances we know about such as pollen, pet dander, and dirt. While some filters claim to be able to capture mold spores, we recommend removing any mold from your home you find, instead of trying to cover up the issue with a finer filter.

Frequently the packaging shows how often your filter should be replaced. There are one-month filters and there are 3-month filters. There are also filters that are two dimensional, flat screens, and you have some that are built accordian style with supporting wire. In our experience, the accordian style filters weather better, and are worth the extra pennies.

You might also consider washable filters, also called reusable filters. Some homeowners like the environmentally friendly aspect of it, since they don't want to add to a wasteyard, and others consider it more convenient to quickly yank out the filter and clean it off rather than making a run to the local hardware store for a filter of the right size. These filters are often designed to endure several years and will save you cash over those years, though they are pricier initially. However, washable filters have to be dried out all the way before placing it back to prevent mold growth in your vents. In addition, most washable filters reportedly have a MERV rating between 1 and 4, and they lose their efficiency over time. Some washable filters have been built with new technology, such as electrostatic air filters, that are meant to essentially improve the MERV rating.

Last, filters are built with different materials. Fiberglass filters are what we see most often, and are the disposable type. Polyester and pleated filters are known to catch more debris, but also reduce the airflow in your home. And there are high efficiency particulate arrestance filters, which you may know as HEPA. While you may be tempted to put in a HEPA filter, just consider that's like putting a MERV 16 filter in your HVAC system and it's highly unlikely that your system was built to handle that kind of resistance.