When it comes to air filtration, MERV ratings are a great way to determine the effectiveness of an air filter. MERV stands for Minimum Efficiency Reporting Value, and it is a rating system designed by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE). Generally speaking, anything under a MERV 13 air filter should provide very efficient air purification in a home without affecting airflow. Meanwhile, air filters with a MERV 14 rating or higher are designed for commercial HVAC systems that can handle the coarsest filter material.
In general, filters with higher MERV ratings are more effective and improve air quality, but they are also more expensive. When considering MERV 8 versus MERV 11 airflow capabilities, it is important to note that raising just three levels of MERV rating can be a smart move that makes air cleaner or a detrimental option for your entire HVAC system. Filters with higher MERV ratings should be changed more frequently (at least every three months) to avoid restricted airflow that can cause the system to operate inefficiently or even damage it. MERV 8 air filters are very common because they are quite a complete option, so you might think that they are excellent in price but poor in performance.
Some of the best air filters for allergies have additional features, such as a carbon layer to eliminate odors. Every time you use your air conditioner or oven, the air filter will become dirty as dust and particles flow through the system and accumulate in the filter. These rely on fiberglass layers to filter particles from the air before they are absorbed by the HVAC system. MERV 17 to MERV 20 filters are commonly used in operating rooms, cleanrooms, and other settings that require absolute cleanliness. According to this article, there is a well-established connection between higher concentrations of particles in outdoor air and poor health outcomes, so it would make sense that filtering these particles out of indoor air could lead to better health outcomes. When deciding which merv filter is best for you, it is important to consider your needs and budget.
In most cases, a MERV 11 air filter isn't too tall for residential use. However, if you need absolute cleanliness in your home or office, then you may want to consider a higher MERV rating. Ultimately, it is important to find an air filter that meets your needs without sacrificing airflow or efficiency.