Are all HVAC air filters the same? No, HVAC air filters vary by quality and size, and some have features that others don't. Mostly we recommend using the filter your HVAC manufacturer recommends pairing up with your installed unit, however you could be tempted to try a different filter type for convenience or to remove more debris from your home. Filters have something called MERV ratings, which range from 1-20. MERV stands for "minimum efficiency reporting value". A higher MERV rating means fewer contaiminants pass through, and it catches finer particulates. This sounds fantastic, and it can be, but a filter that eliminates finer dust and allergens will also clog up quicker, and pressure on your system will increase. If your system has not been engineered to function with this kind of filter, it can actually reduce your airflow throughout your residence, affecting your comfort and energy costs. So what should you know before you buy? Unless you're buying for a hospital, you probably don't need a MERV rating above 13. Fun fact, most residential HVAC systems are specifically designed to work with a filter with a MERV rating below 13, and usually you will discover that quality systems have been made to function with a MERV rating of 8 or 11. All filters with a MERV rating of five should eliminate most of the common nuisances people care about such as pollen, pet dander, and dust. While some filters claim to be able to snag mold spores, we recommend removing any mold from your residence you find, instead of trying to delay the issue with a finer filter. Usually the packaging tells how often your filter ought to be replaced. There are one-month filters and there are 3-month filters. You also have filters that are made flat like screen windows, and you have some that are ridged with supporting wire. In our experience, the accordian style filters fare better, and are worth it for the extra durability. You may also consider washable filters, also sometimes called reusable filters. Some homeowners like the environmentally friendly aspect of it, since they don't add to a wasteyard, and others believe it's more convenient to quickly pull out the filter and wash it off rather than making a special run to the local hardware store for a filter of the correct size. These filters are often created to last several years and will save you cash over those years, though they are pricier initially. However, washable filters should be dried out one hundred percent before inserting it back to eliminate 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 a period of time. Some washable filters have been built with new technology, such as electrostatic air filters, that are meant to essentially improve the MERV rating. Finally, filters are composed from different materials. Fiberglass filters are what we see most often, and are the disposable type. Polyester and pleated filters normally catch more debris, but also lessen the airflow in your home. And there are high efficiency particulate arrestance filters, or HEPA for short. While you may be tempted to buy a HEPA filter, just consider that's like putting a MERV 16 filter in your HVAC system and it's highly unlikely that your equipment was built to handle that kind of resistance.