Air filters function as barriers and keep harmful airborne particles from circulating in your air. They’re an essential part of HVAC systems. They support respiratory health and ensure the air you breathe is clean.  You can prevent potential HVAC system damage and expensive repairs by using an effective air filter and changing it when it's dirty, to ensure your HVAC equipment has a longer lifespan. 

The type of air quality you need in your house and the workload of your HVAC system should be considered when determining how often to change your air filter. High-efficiency filters usually last longer than standard fiberglass filters, which need to be changed every month. You’ll need to switch out your air filter more often if you have a pet, or have someone living in the home who is a smoker or who has allergies. 

Airflow can be restricted when you neglect to change a clogged or dirty air filter, causing your HVAC system to work harder and operate less efficiently.  When you see dust accumulating on surfaces in your home or visible signs of dirt or discoloration, these are signs that your air filter needs to be replaced. If your HVAC system frequently cycles, it's time for air filter replacement. When your allergy symptoms seem to be getting worse, it's an indication you need to replace your filter. Unusual, persistent odors lingering in your airspace may mean your filter change is overdue. If your utility bill unexpectedly increases, change out your filter. Replace your air filter at the recommended time to ensure you have clean air and to keep your HVAC system properly functioning.

When you want to determine the size of the air filter your HVAC system uses, check your existing one for the dimensions printed on its frame. Ask an HVAC professional for assistance or to measure the slot if you don't have the filter you were previously using. The measurements may also be included in your HVAC system manual. Before purchasing a replacement filter, verify the width, height, and thickness to make sure you’re getting the one that fits so your HVAC system will work correctly.

Air filters' ability to capture airborne particles, and their effectiveness, are evaluated and measured by MERV ratings (Minimum Efficiency Rating Value) on a scale from 1 to 16. MERV filters with higher ratings trap finer particles, but might restrict air flow and affect HVAC performance. Your HVAC system will function better if you choose an air filter in the appropriate size with a MERV rating that balances air flow and filtration.