Does Furnace Filter Thickness Matter? How to Choose the Right One?


If you have a furnace at home, the dirty filter might start giving you trouble every 2 to 6 months, at which point it would benefit you to get a new filter. The issue is that filters come in a broad range of sizes and thicknesses to support a wide range of furnaces. It can be challenging to choose the appropriate filter.

In addition to filter sizes, thickness plays an essential role when determining the appropriate size of a furnace filter and achieving an appropriate fit to achieve optimal performance. Are you unsure which choice would be best for you? Continue through this article to learn how to determine the appropriate filter thickness required for your furnace.

What Is a Furnace Filter?

The primary function of your furnace filter is to keep the blower fan safe from the dust, dirt, and other contaminants that enter the return duct via the filter. Throughout the day, dust and debris can be found inside homes. When you use a blower to circulate the air in your house, it also circulates the particles in the air, which eventually make their way into your system. Therefore, a furnace filter is very important.

All of the contaminants travel through the filter in your furnace, which keeps them from traveling through the rest of the systems and being distributed throughout your rooms. These filters also assist in an enhancement in the air quality inside your home. You can get custom furnace filters from many different residential air filters supplier, like Custom Filters Direct.

Furnace Filter Thickness Matters

Most professionals in the field of heating, ventilation, and air conditioning (HVAC) would tell you that thicker filters perform far better than the standard thin furnace filters. If you are looking to enhance the air quality in your home and are considering buying a wider air filter, it is highly recommended that you also pay attention to the MERV rating.

Filters with higher MERV ratings are most effective when it has a thickness of at least 4 inches. This is because higher MERV ratings can capture very tiny particles, which causes pollutants to rapidly accumulate. The importance of thickness can be attributed to a variety of factors, some of which include the following:

–          Large Surface Area

A filter with a big surface area will produce a significantly greater airflow, eliminating all undesired pollutants from the air in a complete cycle. This will result in a superior filtration rate, which will eventually result in cleaner air. The thicker filter will prevent as much material from falling through the openings, which will result in high air quality. Additionally, it works quite well even in bigger spaces.

–          Improved Longevity

As a result of fewer blockages and more filtration capacity in a single pass, the air filter is able to provide the filtration process with a long productive life. Therefore, you do not regularly need to have the filter changed or get it maintained in any other way.

–          Reduced Blockage

A clogged filter is one of the most prevalent issues with any standard air filter. Their blockage systems are the fundamental distinction between thick and thin filters. The thinner the filter, the more likely it is to get clogged, requiring more regular cleaning and maintenance. Thicker filters, on the other hand, don’t require this.

Which Filter Thickness Is Best for My Furnace?

The length and breadth of a typical furnace filter have little to do with how effective it is. However, the efficacy of the filter is greatly affected by its thickness. Therefore, choosing the ideal thickness for your filter might bring you a lot of advantages. In most homes, the furnace filter’s thickness will be 1 inch or 5 inches. Generally, filters with a thickness of 1 inch are the most affordable, and the price increases with increasing thickness.

Although a filter with a thickness of 4 inches is more effective than one with a thickness of 1 inch, the appropriate thickness for your furnace will depend on its size. If you measure the filtering slot and determine that it is big enough to fit the thick filter, then you can use it without any issues. The cost of replacing a 4-inch filter every three to four months could be unaffordable for many of us. Therefore, it’s also possible to replace the thicker filter with a thinner one. 

The thickness of the majority of air filters is around one inch; however certain systems can support filters anything between two to five inches in thickness. In addition, we observed that the thicker filter, the better it functions, and the longer the intervals between replacements it has.

Are Thicker Filters More Effective?

Firstly, thick air filters seem to be the preferable option. Filters with a higher surface area, such as those used in furnaces and air conditioners, have a longer productive life. A 1inch air filter would require to be replaced every month, but a 4-inch air filter can last for up to six months. The abilities of the furnace have a one-to-one relationship with the level of filter thickness used in the furnace. The use of a wider air filter has a number of remarkable advantages, such as:

  • Increases energy efficiency.
  • Enhanced levels of air quality.
  • Enhanced filtration process.
  • A larger surface area can trap more pollutants.
  • Improved longevity and longer times intervals between maintenance.

Final Verdict

The appropriate thickness of your furnace’s filter can make a significant impact on both its functioning and its maintenance. Utilizing the appropriate thickness can result in a number of positive outcomes. However, using a filter with a greater thickness is always the preferable alternative. It is important to choose the appropriate filter and perform routine maintenance on a regular basis to save costs and maximize efficiency.