When it comes to air filters, the MERV rating system is designed to determine the filter's ability to remove particles from the air. The acronym stands for Minimum Efficiency Reporting Value, and it's a scale that ranges from 1 to 16. The higher the MERV rating, the more efficient the filter is at trapping particles. In most cases, a MERV 11 air filter isn't too tall for residential use. 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. The MERV rating you choose between 7 and 13 depends on the level of filtration you need. If your family has allergies or asthma, a higher MERV score will be good for you. If your family doesn't have any difficulty breathing, a lower filter, such as a 7, will save you some money on your energy bill.
Many homeowners don't pay attention to their MERV rating of the filter, but if you're a person with pets or allergies, then it will be beneficial for you to worry more. Filters with a MERV rating of 8 to 13 are usually high-end filters for domestic use or high-quality commercial filters. Air filters with MERV ratings higher than 13 also tend to restrict airflow because they have smaller pores to capture smaller particles. A MERV 9 will trap less than 50% of particles with a size of 1.0-3.0 microns, the MERV 10 will stop up to 64%, the MERV 11 will get up to 79%, and the MERV 12 is capable of trapping up to 89%. ASHRAE 52.2 describes methods and procedures for evaluating the performance of air filters based on particle size.
Filters in the MERV 5-8 range can also trap particles with a size of 3.0-10.0 microns, but are more efficient in doing so. Most air filters have arrows marked to indicate the direction in which air is supposed to flow through them. If the air cleaner is on the return grille inside your home, the arrow should point toward the wall or ceiling. One thing to keep in mind is that a MERV 11 air filter may need to be changed a little more frequently than a MERV 8 air filter. However, if you are concerned about outdoor air pollution, family members with respiratory problems, pets are in the house, then a higher MERV rating might be a good idea. In general, filters with a MERV 16 rating or lower are considered HVAC system grade filters for residential, commercial, and general hospital use.
When the air filter is dirty, less air can travel through the HVAC system, increasing operating times and reducing efficiency. Choosing an appropriate MERV rating for your home or business is essential for ensuring optimal indoor air quality and energy efficiency. It's important to consider your specific needs when selecting an air filter so that you can get the best performance out of your HVAC system. If you're still unsure about what type of MERV air filter you need for your home or business, contact an experienced HVAC technician who can help you make an informed decision.