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 equipment.

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

A bigger value indicates the filter can catch finer substances. This sounds outstanding, but a filter that catches finer dirt can become blocked more rapidly, increasing pressure on your system. If your equipment isn’t designed to function with this model of filter, it may decrease airflow and create other problems.

Unless you live in a medical facility, you probably don’t need a MERV ranking higher than 13. In fact, the majority of residential HVAC equipment is specifically designed to work with a filter with a MERV rating under 13. Sometimes you will find that good systems have been made to operate with a MERV ranking of 8 or 11.

All filters with a MERV rating of 5 should catch many everyday annoyance, like 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 mask the trouble with a filter.

Usually the packaging indicates how often your filter should be exchanged. From what we’ve seen, the accordion-style filters last longer, and are worth the added price.

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

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