How Thick Should Your AC Filter Be?

Most air filters are 1 inch thick, but some systems can accommodate filters that are 2 to 5 inches thick. In our tests, we found that the thicker the filter, the better it works and the longer the replacement intervals. This means it's better for you and your heating, ventilation and air conditioning (HVAC) system. The majority of oven and AC filter sizes come with a thickness of 1 inch.

While this is standard in many homes, some are equipped with thicker filters. These have the ability to handle more buildup, which means you'll need to change them less frequently. In addition, a coarser filter can trap more particles than a standard filter. However, these filters can sometimes restrict airflow, which can lead to air and system quality problems. Another important difference between 1-inch and 2-inch filters is their efficiency.

Thicker filters are more efficient for several reasons. However, there are some cases where 1-inch and 2-inch filters may be on par when it comes to efficiency. This all depends on the MERV rating of the filter. The MERV rating is the rating that measures how well the filter blocks particles. First, 4-inch filters cover a higher range of MERV ratings, with a slight overlap with 1-inch filters.

On the other hand, 1-inch filters are decent enough to remove typical dust, pet dander, and other particles up to 3 microns in size. That said, a thinner 1-inch filter with a high MERV rating would clog up very quickly (compared to a 4-inch pleated filter), since there is less surface area available to trap contaminants. In most cases, a standard filter cannot be replaced with a true HEPA filter because the ductwork is not designed for it. At the same time, a thicker filter is less restrictive and will allow a better flow of purified air. However, before completing this step, it is important to understand the difference between nominal and actual filter sizes. Most white pleated air filters are inherently the same within each efficiency level, and vary slightly, if at all, between brands.

If you live in a very hot climate such as Arizona, there are return grilles throughout the house, with a filter that is the right size for each vent. Alternatively, you can use a 1-inch thick filter in compartments that can accommodate a deeper filter. From filtering out harmful contaminants to keeping your HVAC unit running efficiently, these products have several benefits.