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 installing the filter your HVAC manufacturer recommends pairing up with your installed unit, though you could be tempted to try another filter type for convenience or to remove extra debris from the air. All filters have 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 like a good thing, and it can be, but a filter that eliminates finer dust and allergens will also stop up faster, and pressure on your HVAC equipment will go up. If your system has not been crafted to operate with this kind of filter, it can reduce your airflow throughout your residence, putting the hurt on your comfort and energy expenses. So what should you know before you buy? Unless you're a hospital, you simply don't need a MERV rating above 13. Truth be told, most residential units 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 work with a MERV rating of 8 or 11. All filters with a MERV rating of five should block most of the major nuisances people care about such as pollen, pet dander, and dust. While some filters claim to be able to capture mold spores, we recommend hiring a pro to clean out any mold from your residence you find, instead of trying to hide the issue with a finer filter. Often the packaging shows how often your filter is recommended to be replaced. There are one-month filters and there are 3-month filters. You also have filters that are one flat piece, and you have some that are ridged with supporting wire. In our experience, the accordian style filters fare better, and are worth a little extra. You may 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 dump, and others think it more convenient to simply slide out the filter and hose it off rather than making a special run to the local hardware store for a filter of the proper size. These filters are often created to last several years and will save you cash over those years, though they cost more initially. However, washable filters do need to be dried out all the way before inserting it back to eliminate mold growth in your vents. In addition, most washable filters typically have a MERV rating between 1 and 4, and they lose their efficiency over time. Some washable filters have been built with updated technology, such as electrostatic air filters, that are meant to basically improve the MERV rating. Finally, filters are made of different materials. Fiberglass filters are what is bought most often, and are the disposable type. Polyester and pleated filters can catch more debris, but also reduce the airflow in your residence. And there are high efficiency particulate arrestance filters, or HEPA for short. While you could be tempted to use a HEPA filter, keep in mind 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.