How Often Should Commercial HVAC Filters Be Changed: A Comprehensive Guide

It's no secret that HVAC systems play a crucial role in maintaining the comfort and air quality of commercial spaces. One important aspect of HVAC maintenance is the regular replacement of air filters. In this in-depth guide, we'll discuss the factors determining the frequency of commercial HVAC filter changes, the implications of not changing filters regularly, and how to choose the correct filters for your commercial HVAC system.

Understanding Air Filters and Their Function

Air filters are integral components of HVAC systems. They are typically fabricated from spun fiberglass or pleated paper and framed with cardboard for stability and rigidity. Air filters are strategically positioned within the return air duct of your HVAC system to prevent contaminants from circulating within the air or entering the HVAC system.

Most filters are engineered to block out dust, dirt, pet hair, lint, mold, bacteria, and more. The efficacy of an air filter in trapping these pollutants is determined by its Minimum Efficiency Reporting Value (MERV) rating.

The Significance of MERV Ratings

The MERV rating of an air filter indicates how efficiently the filter can stop dust and other contaminants from passing through the filter and into the air stream. Filters with higher MERV ratings are more effective in trapping small particles than filters with lower MERV ratings.

Using an air filter with a MERV rating higher than what your HVAC system manufacturer recommends can impair the system's performance1. The tiny pores in more highly rated filters can reduce the system’s efficiency, decrease indoor air quality, and strain the system’s fan due to increased resistance to airflow

Frequency of Changing Commercial HVAC Filters

Generally, air filter manufacturers and HVAC companies recommend changing your air filter every 90 days. However, this can vary based on the location of your commercial building, whether you have pets and the age of your HVAC system and equipment.

For instance, if the system is located in a dusty, dry climate or there are pets in the building, consider changing your filter every 60 days. If multiple pets or people frequently occupy the commercial space with allergies or respiratory conditions, it's recommended to change the filter every 20-45 days.

Commercial spaces that are not frequently used, like vacation or vacant homes, can typically wait to change out filters every 9-12 months. Essentially, the more regularly your commercial space is used, the more often you must change your air filter.

Consequences of Not Changing Air Filters Regularly

If you neglect to replace your air filter, it will eventually fail to filter the air properly, allowing dust and contaminants to infiltrate the HVAC system. Dust can jam the moving parts of an AC system, such as fan motors and valves.

This restricted airflow strains the system and causes it to draw more power to overcome the obstacle, making the unit less energy-efficient and more prone to breakdowns.

Other contaminants that can enter a dirty system include allergens and spores. It's important to note that the only type of filters that can capture these are High-Efficiency Particulate Air (HEPA) filters. These filters, made of a much finer mesh than others, can screen out tiny particles such as allergens, pollen, dander, and mold spores.

Selecting the Best Air Filter for Your Commercial HVAC System