Are all HVAC air filters the same?
No, HVAC air filters vary in quality and dimensions, and some have features that others don't. In most situations we advise installing the filter your HVAC manufacturer says to pair with your equipment.
All filters are classified with MERV ratings, which go from 1–20. MERV means minimum efficiency reporting value.
A higher rating means the filter can trap smaller particles. This sounds outstanding, but a filter that catches finer dirt can become blocked more quickly, increasing pressure on your system. If your system isn’t created to work with this model of filter, it may restrict airflow and lead to other troubles.
Unless you live in a medical facility, you probably don’t require a MERV ranking higher than 13. In fact, the majority of residential HVAC units are specifically engineered to run with a filter with a MERV rating under 13. Frequently you will discover that good systems have been designed to work with a MERV ranking of 8 or 11.
All filters with a MERV ranking of 5 should trap most of the common nuisances, like pollen, pet dander and dust. Some filters claim to be able to catch mold spores, but we suggest having a professional get rid of mold rather than trying to hide the problem with a filter.
Sometimes the packaging indicates how frequently your filter should be replaced. In our experience, the accordion-style filters work better, and are worth the additional expense.
Filters are created from differing materials, with one-use fiberglass filters being the most common. Polyester and pleated filters grab more debris but may reduce your unit’s airflow. Then there are HEPA (high efficiency particulate air) filters.
While you might be interested in using a HEPA filter, remember that's like installing a MERV 16 filter in your heating and cooling system. It’s highly unrealistic your unit was made to work with amount of resistance. If you’re worried about indoor air quality. This unit works along with your HVAC system.