Are all HVAC air filters the same?

No, HVAC air filters differ in quality and dimensions, and some have specifications that others don't. In most situations we advise installing the filter your HVAC manufacturer suggests pairing with your equipment.

All filters are classified with MERV ratings, which vary from 1–20. MERV stands for minimum efficiency reporting value.

A bigger value indicates the filter can grab finer particulates. This sounds outstanding, but a filter that stops finer substances can become obstructed faster, raising pressure on your equipment. If your equipment isn’t made to run with this type of filter, it could restrict airflow and cause other troubles.

Unless you reside in a medical facility, you probably don’t have to have a MERV level higher than 13. In fact, many residential HVAC units are specifically engineered to operate with a filter with a MERV level lower than 13. Sometimes you will discover that decent systems have been engineered to operate with a MERV level of 8 or 11.

All filters with a MERV level of 5 should catch most of the common annoyance, like pollen, pet dander and dust. Some filters say they can trap mold spores, but we advise having a professional remove mold instead of trying to hide the trouble with a filter.

Often the packaging shows how frequently your filter should be replaced. From what we’ve seen, the accordion-style filters hold up better, and are worth the extra expense.

Filters are made from different materials, with single-use fiberglass filters being standard. Polyester and pleated filters grab more dirt but may limit your unit’s airflow. Then there are HEPA (high efficiency particulate air) filters.

While you might want to use a HEPA filter, keep in mind that's like installing a MERV 16 filter in your HVAC system. It’s very unrealistic your system was designed to handle that kind of resistance. If you’re concerned about indoor air quality in Austin, think over installing a HEPA-grade air filtration system. This unit works in tandem with your HVAC system.