Are all HVAC air filters the same?

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

All filters are assigned MERV ratings, which go from 1–20. MERV stands for minimum efficiency reporting value.

A bigger value demonstrates the filter can grab finer substances. This sounds good, but a filter that traps finer substances can become blocked more quickly, heightening pressure on your unit. If your equipment isn’t created to work with this model of filter, it could reduce airflow and lead to other troubles.

Unless you are in a hospital, you more than likely don’t need a MERV level greater than 13. In fact, most residential HVAC units are specifically designed to run with a filter with a MERV level lower than 13. Occasionally you will learn that quality systems have been engineered to run with a MERV ranking of 8 or 11.

All filters with a MERV ranking of 5 should trap many common annoyance, including pollen, pet dander and dust. Some filters say they can trap mold spores, but we advise having a professional eliminate mold instead of trying to mask the issue with a filter.

Sometimes the packaging shows how regularly 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 single-use fiberglass filters being the most common. Polyester and pleated filters trap more debris but may decrease your system’s airflow. Then there are HEPA (high efficiency particulate air) filters.

While you might want to use a HEPA filter, remember that's like installing a MERV 16 filter in your HVAC unit. It’s highly doubtful your equipment was made to work with kind of resistance. If you’re worried about indoor air quality in Gaithersburg, think over getting a HEPA-grade air filtration system. This equipment works in tandem with your comfort system.