Are all HVAC air filters the same?

No, HVAC air filters differ in quality and size, and some have specs that others don't. In most cases we suggest getting the filter your HVAC manufacturer recommends pairing with your unit.

All filters are assigned MERV ratings, which range from 1–20. MERV is short for minimum efficiency reporting value.

A larger value means the filter can catch finer particles. This sounds outstanding, but a filter that catches finer dirt can become blocked faster, increasing pressure on your equipment. If your unit isn’t designed to function with this type of filter, it may decrease airflow and create other problems.

Unless you live in a medical facility, you probably don’t need a MERV level greater than 13. In fact, the majority of residential HVAC units are specifically designed to work with a filter with a MERV rating lower than 13. Sometimes you will find that good systems have been made to run with a MERV level of 8 or 11.

All filters with a MERV rating of 5 should catch many everyday annoyance, including pollen, pet dander and dust. Some filters claim to be able to catch mold spores, but we recommend having a professional eliminate mold as opposed to trying to conceal the problem with a filter.

Sometimes the packaging indicates how often your filter should be changed. From what we’ve seen, the accordion-style filters work better, and are worth the added price.

Filters are manufactured from different materials, with disposable fiberglass filters being standard. Polyester and pleated filters grab more dust but may limit your system’s airflow. Then there are HEPA (high efficiency particulate air) filters.

While you may want to use a HEPA filter, know that's like adding a MERV 16 filter in your HVAC system. It’s extremely doubtful your unit was created to handle that level of resistance. If you’re troubled by indoor air quality in San Antonio, think about getting a HEPA-grade air filtration system. This equipment works in tandem with your heating and cooling system.