Are all HVAC air filters the same? No, HVAC air filters vary due to 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 equipment, but you may be tempted to try another filter type for convenience or to remove extra pollutants from the air. Filters have MERV ratings, which range from 1-20. MERV means "minimum efficiency reporting value". A higher MERV rating means fewer pollutants pass through, and it blocks finer particulates. This sounds fantastic, and it can be, but a filter that stops finer dust and allergens will also stop up more often, and pressure on your unit will increase. If your system has not been engineered to function with this kind of filter, it can actually reduce your airflow within your residence, putting the hurt on your comfort and energy expenses. So what should you do? Unless you're buying for a hospital, you probably don't need a MERV rating above 13. Truth be told, most residential HVAC systems are specifically designed to work with a filter with a MERV rating below 13, and usually you will learn that higher end systems have been made to operate with a MERV rating of 8 or 11. All filters with a MERV rating of five should eliminate most of the everyday nuisances we know about such as pollen, pet dander, and dirt. While some filters claim to be able to catch mold spores, we recommend hiring a pro to clean out any mold from your home you find, instead of trying to delay the issue with a finer filter. Often the packaging tells how often your filter is recommended 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 a little extra. You might also consider washable filters, also called reusable filters. Some homeowners like the environmentally friendly aspect of it, as they don't pile onto a dump, and others think it more convenient to simply 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 endure several years and will save you money over those years, though they are more expensive initially. However, washable filters should be dried out all the way before placing it back to stop mold growth in your vents. In addition, most washable filters usually have a MERV rating between 1 and 4, and they lose their efficiency over the years. 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 is bought most often, and are the disposable type. Polyester and pleated filters are known to catch more debris, but also decrease the airflow in your residence. And there are high efficiency particulate arrestance filters, or you might recognize the acronym HEPA. While you could be tempted to use a HEPA filter, just understand that's like putting a MERV 16 filter in your HVAC system and it's not unlikely that your equipment was constructed to handle that kind of resistance.