What merv to filter smoke?

Most ovens and HVAC systems can accommodate a MERV 13 filter without creating problems for the equipment, provided that the filter is replaced frequently. MERV stands for “minimum efficiency information value”, and is a measure of how well a central air filter removes particles from the air. Medium MERV filters provide much more filtration than basic MERV 1-4 filters with central air systems, which capture only visible to the naked eye contaminants, such as pet hair and dust rabbits, but not fine particles such as smoke. If you're not sure what type you have, these basic filters often come included with the equipment, are the most economical filter replacement option, and usually look like a transparent blue or green thread mesh.

MERV 8 filters are not the best option for residential HVAC systems, according to ASHRAE. While MERV 8 is known to be effective at filtering contaminants such as pollen, dust mites, sawdust, mold spores, and lint from the air, higher MERV ratings will clean the air even more. MERV 13 filters, for example, also remove bacteria, tobacco smoke, car fumes, insecticide dust, pet dander, and more. The American Lung Association recommends a filter with a MERV rating of 13 or higher (as long as it works with your central air system).

MERV stands for minimum efficiency reporting value, and the higher it is, the more contaminants the filter will remove. While ASHRAE recommends MERV 13 and 14, it's best to select a filter with the highest possible MERV rating for your specific HVAC system. The EPA recommends filters with a rating of at least MERV 13, or a rating “as high as the system fan and filter slot can accommodate.” If your home's HVAC system is not capable of handling MERV 13, opt for a filter with the next highest possible rating. 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.

Unfortunately, not all filters are created equal, and marketing material from different filter brands can be confusing and often misleading. Filter technology has grown by leaps and bounds over the years, and MERV ratings are designed to help us determine the most effective and efficient air filter options for heating and cooling systems and more.