Are all HVAC air filters the same? No, HVAC air filters vary by quality and size, and some have technology that others don't. Usually we recommend using the filter your HVAC manufacturer recommends pairing up with your installed unit, though you could be tempted to try a different filter type for convenience or to remove additional pollutants from your home. Filters have something called MERV ratings, which range from 1-20. MERV means "minimum efficiency reporting value". A higher MERV rating means fewer contaiminants pass through, and it blocks finer particulates. This seems obviously good, and it can be, but a filter that catches finer dust and allergens will also stop up more often, and pressure on your HVAC equipment will increase. If your system has not been crafted to work with this kind of filter, it can decrease your airflow throughout your home, impacting your comfort and energy costs. So what should you look for? Unless you're a hospital, you simply don't need a MERV rating above 13. In fact, most residential systems are specifically designed to work with a filter with a MERV rating below 13, and frequently you will learn that more expensive systems have been made to work with a MERV rating of 8 or 11. All filters with a MERV rating of at least 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 capture mold spores, we recommend removing any mold from your home you find, instead of trying to hide the issue with a finer filter. Frequently the packaging indicates how often your filter ought to be replaced. There are one-month filters and there are 3-month filters. There are also filters that are one flat piece, and you have some that are pleated with supporting wire. In our experience, the accordian style filters hold up better, and are worth it for the extra durability. You might also consider washable filters, also known as reusable filters. Some homeowners like the environmentally friendly aspect of it, since they don't pile onto a landfill, and others consider it more convenient to simply yank out the filter and wash it off rather than making a run to the local hardware store for a filter of the proper size. These filters are often created to work several years and will save you cash over time, though they are more expensive initially. However, washable filters do need to be dried out thoroughly before inserting it back to stop 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 tech, such as electrostatic air filters, that are meant to essentially improve the MERV rating. And lastly, filters are made of different materials. Fiberglass filters are what is commonly used, and are the disposable type. Polyester and pleated filters can catch more debris, but also decrease the airflow in your residence. And there are high efficiency particulate arrestance filters, or HEPA for short. 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 not unlikely that your equipment was built to handle that kind of resistance.