Are all HVAC air filters the same? No, HVAC air filters vary in quality and size, and some have technology that others don't. In most cases we recommend installing the filter your HVAC manufacturer recommends pairing up with your installed unit, though you may be tempted to try some other filter type for convenience or to remove extra contaminants from the air. Filters have MERV ratings, which range from 1-20. MERV stands for "minimum efficiency reporting value". A higher MERV rating equates to fewer pollutants pass through, and it captures finer particulates. This sounds fantastic, and it can be, but a filter that stops finer dust and debris particles will also clog up quicker, and pressure on your unit will increase. If your system has not been engineered to operate with this kind of filter, it can decrease your airflow within your residence, putting the hurt on your comfort and energy costs. So what should you know before you buy? Unless you live in a hospital, you probably don't need a MERV rating above 13. In fact, most residential HVAC 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 operate with a MERV rating of 8 or 11. All filters with a MERV rating of five should block most of the major nuisances we know about such as pollen, pet dander, and lint. While some filters claim to be able to catch mold spores, we recommend removing any mold from your home you find, instead of trying to hide the issue with a finer filter. Usually the packaging shows 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 weather better, and are worth a little extra. You could also consider washable filters, also called reusable filters. Some homeowners like the environmentally friendly aspect of it, since they don't pile onto a dump, and others believe it's more convenient to simply pull 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 money over those years, though they cost more initially. However, washable filters should be dried out one hundred percent before returning it back to eliminate mold growth in your ductwork. 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 tech, such as electrostatic air filters, that are meant to basically improve the MERV rating. Last, filters are made of different materials. Fiberglass filters are what is commonly used, and are the disposable type. Polyester and pleated filters normally 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 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 equipment was made to handle that kind of resistance.