Your MERV Filter: Pick A Number, But Just Any Number?
Air filters are rated by MERV, or Minimum Efficiency Reporting Value. The scale, which ranges from 1 to 20, is based on the percentage of microscopic particles that the filter will remove from the air. It focuses on microscopic particles (those between 0.3 and 10 microns in size) because those tend to be the most dangerous to your health: things like viruses, bacteria, mold, spores and smoke all fall into that size range. (Plus, if air filters have such small gaps that microscopic particles cannot pass through them, any larger particles will also become trapped in the filter.)
Choosing the right MERV number for your home’s air filter is important. The standard filters that come with most HVAC systems rate very low on the scale and will do little to clear your air of microscopic health hazards. Such filters are really just designed to keep hair, lint and other large particles out of your A/C and furnace. But it is also possible to choose an air filter with a MERV rating that is too high. In order to achieve the near 100 percent efficiency that is required to rank at the top of the scale, an air filter has to be so dense that very little air can pass through it. To keep from blocking the airflow through your HVAC system, these top-rated filters have to be bigger – and that would likely require modifications to your air duct system, to accommodate the filter’s size.
Because of this, the EPA has stated that filters with a MERV rating of 7 to 13 are the best choice for most homes, doing a good job of cleaning the air without significantly reducing air flow. The right filter rating for your home really depends on the specifics of your HVAC system, though.
To find out which air filter would be the best fit for your home, contact us at Sobieski Services. We’ll be happy to help.
Our goal is to help educate our customers in Wilmington, Delaware and surrounding areas about energy and home comfort issues (specific to HVAC & plumbing systems).
Image Credit: ShellyS