top of page

What Size Air Filter Works Best?

If your furnace is located in the attic of your home, chances are you have a choice of whether or not you want to use a 1-inch, 4-inch, or sometimes even a 5-inch filter. But, how do you choose which one to use? Is one better than the other?

HVAC Filter Sizes

Do Air Filters Really Work?

One of the most common reasons for poor indoor air quality and HVAC malfunction is restricted airflow caused by the failure to regularly replace the air filters. Your A/C filter, otherwise known as your HVAC filter is your first line of defense against the collection of indoor airborne allergens like dust, dirt, pollen, pet dander, mold, bacteria, viruses, and other contaminants and volatile organic compounds on your furnace coils, within your air ducts, and even releasing back into the air you're breathing within your home or occupied dwelling. These filters often use static electricity or sometimes electrostatic technology that attracts the contaminants and allows clean, healthy air to circulate through your air ducts and your home. Without regular replacement however, the filter loses its efficiency and filters less of the allergens, pollutants, and contaminants it's intended to filter.

How Often Should Filters Be Replaced?

Air Filter Replacement

The average filter width is 1-inch, and 4-inches. The size of the filter dictates how often you should replace your filter. It is recommended that 1-inch filters are replaced at least every 90 days and although the 4-inch filters are larger they are also recommended to be replaced around every 90 days. However, 4-inch filters can have a longer filter life compared to 1-inch filters. Although they can last longer between filter replacements, the filter still collects the same amount of pollutants within the same amount of time as compared to the 1-inch filter. The 4-inch filter can last up to 6-months and we recommend that you do not wait any longer to replace the filter as the efficiency drastically decreases.

What Size Filter Should You Use?

The size of the filter in which you use is up to you. However, a replacement schedule is a

Fresh Air Matters Filter Replacement Plans

necessity when deciding which size filter to use. If you often forget about replacing your filters, you should contact Fresh Air Matters regarding a filter replacement plan, however if you decide to replace the filters yourself, a 1-inch filter would be the best option in both price and efficiency. Without a regular filter replacement plan, a 4-inch filter may be best if you would rather wait as long as possible in between filter replacements.

What Happens If You Don't Regularly Replace Your Filter?

The purpose of your air filter is to clean the air by collecting the allergens, pollutants, and contaminants from within the circulating through your home or occupied dwelling. When the filters are not regularly replaced, the efficiency of the filter diminishes and those impurities eventually re-enter the air which then negatively impacts your air quality and your overall health. As the impurities pass through or are released from your filter they can collect on your furnace coils which then restricts the air flow, which negatively impacts your air quality, also making your system work harder to heat and/or cool your home and causes essential part breakdown, leading to sometimes avoidable and costly repairs.

If you live in North Texas and you're interested in establishing a filter replacement plan in which a Fresh Air Matters technician provides the filters, replaces them for you, and cleans your return vents on the same day, at the same time, every 30-90 days, contact us or go visit for scheduling or other information.

Fresh Air Matters Clean Indoor Air Products & Services

Recent Posts

See All


bottom of page