How Often Should You Replace Your Furnace Filter?

As the leading provider of expert heating services in Wake Forest, NC, we maintain our clients’ HVAC systems for optimal performance all year long with regular maintenance services. However, there are some routine maintenance tasks you should perform between our service visits, and keeping a clean air filter in your system is at the top of that list. 

Our clients often ask, “How often should you change your furnace filter?” Read on as Tech-on-Deck Heating, Air, & Electric answers that question and provides additional information about proper air filtration for your system.

Why Furnace Filters Matter in Wake Forest

Filters do more than just protect your furnace and HVAC system. They promote health and improve indoor air quality by keeping contaminants like dust, pollen, pet dander, and mold spores out of your living space. Our region’s seasonal climate and high pollen counts make proper filtration even more important.  

Letting a filter go when you should replace it leads to: 

• Restricted airflow: Clogged filters force furnaces to work harder, leading to insufficient heat and increased overheating risks.
• Higher energy bills: Your system uses more energy to push air through a dirty filter, which shows up directly in monthly utility costs.
• Poor air quality: A saturated filter cannot effectively trap contaminants, meaning they will recirculate through your living space. 
• Potential system damage: Excessive strain on the blower motor leads to unnecessary expensive repairs or premature system failure.

Understanding MERV Ratings

When selecting a furnace filter, MERV ratings (Minimum Efficiency Reporting Value) indicate filtration efficiency. Here’s how to interpret the ratings:

• MERV 1-4: These provide basic filtration, mostly for preventing dust buildup in the system.
• MERV 5-8: These are better for homes without pets or allergy concerns.
• MERV 9-12: This range is usually ideal for homes with pets or mild allergy issues.
• MERV 13-16: These work best for allergy sufferers and improve air quality — but may overly restrict airflow in some HVAC systems.

How Often Should You Change Your Furnace Filter?

How often you change your air filter depends on the design and quality of the filter you use. These are the general guidelines we recommend:  

Fiberglass Furnace Filters (1-inch thick)

Change these affordable and easy-to-replace filters every 30 days. These are less effective at trapping small particles and are best for homes without pets or allergy sufferers. 

Pleated Filters (1 to 4 inches thick)

Change this design every 60 to 90 days. Pleated filters capture more dust, pollen, and pet dander than fiberglass and are better suited for allergy-sensitive homes.

High-Efficiency Filters (MERV 11-16)

These are better for homes with more serious allergy or respiratory concerns and you should change this type every 6 to 12 months. Make sure your HVAC system can handle the airflow restrictions that these filters present, as they trap finer dust, bacteria, and mold spores. 

Washable and Reusable Filters

Follow manufacturer instructions when cleaning these types every 30 to 90 days. Reusable filters present an eco-conscious and more sustainable solution. However, be certain to completely dry these types to prevent mold growth. 

Factors That Affect Furnace Filter Replacement

Other factors impact the question, “How often should you change your furnace filter?”:

• Pets in the home: Pet dander and fur can quickly clog filters.
• Allergies or asthma: If anyone in your household suffers from allergies or respiratory problems, consider a high-MERV filter and change it every 30 to 60 days.
• Number of occupants: More people in the home generate more dust, which often requires more frequent filter changes.
• Air quality in Wake Forest, NC: Our area experiences seasonal pollen surges and typically high humidity, which can accelerate filter clogging.

HVAC usage: If your heating or cooling system runs constantly, your filter naturally accumulates dust faster. Especially during peak heating or cooling seasons, check your filter at least once a month.