How to Choose the Best Furnace Air Filter

Posted on February 4, 2025

You should try to replace your furnace's air filter every 30-90 days, depending on how much your furnace has been running. During the coldest months, you may need to replace the furnace air filter every 30 days. Replacing your furnace's filter regularly improves your furnace's energy efficiency and can also improve the air quality in your home. There are several types of furnace filters that serve a variety of purposes. Some promote airflow, some work to improve air quality conditions for those with allergies or asthma, and more.

How do you know which furnace filter is the best fit for you? In this article, we'll dive into some of the different types of filters available and how they might benefit you.

Reading MERV Ratings

Air filters have a "MERV" rating, or Minimum Efficiency Reporting Value. The higher this rating, the better the filter will trap contaminants in your air. If you have asthma or allergies, you may want to consider purchasing a filter with a higher MERV rating.

Fiberglass Filters

Fiberglass air filters are the most basic and affordable option. They are designed to protect your furnace by trapping larger particles such as dust and lint. However, they do not significantly improve indoor air quality since they are less effective at capturing smaller pollutants like pollen or pet dander. These filters are best suited for homes without allergy concerns.

Pleated Filters

Pleated air filters have a greater surface area, which allows them to capture more contaminants, including dust, pollen, and mold spores. They are more efficient than fiberglass filters and are available in different MERV (Minimum Efficiency Reporting Value) ratings. Pleated filters are an excellent choice for homeowners who want a balance between cost and efficiency. They are excellent for pet owners because they filter pet dander.

Electrostatic Filters

Electrostatic air filters use static electricity to attract and trap particles in the air. They can be either disposable or washable. These filters are highly effective at capturing allergens and small particles, making them a good option for families with pets or individuals with allergies. The washable filters typically have a MERV rating of 8, while the disposable electrostatic filters have a MERV rating of 10.

HEPA Filters

HEPA (High-Efficiency Particulate Air) filters are the gold standard for air filtration, capturing up to 99.97% of airborne particles as small as 0.3 microns. These filters are ideal for homes with severe allergy or respiratory concerns. However, they may require special adaptations to work with your furnace due to airflow restrictions. Most of the time, these filters are only used in Medical facilities.

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