The material of a filter is quickly clogged with contaminants, reducing air flow through the HVAC system and eliminating the effective removal of contaminants. A 4-inch filter provides more surface space to trap contaminants, facilitating proper airflow and continuous removal of contaminants. The short answer? A 4-inch filter will last longer and provide better air quality for your home. First, 4-inch filters cover a higher range of MERV ratings, with a slight overlap with 1-inch filters.
With a filter of 4, you'll get at least an 8 MERV rating. With higher ratings of up to 16, you can control supermicrocontaminants, such as bacteria, viruses and dust particles. Virtually any HVAC professional will tell you that thicker filters work better than common 1-inch oven filters. Thicker filters, known as multimedia filters, are usually 4 to 5 inches thick compared to the ubiquitous 1-inch filters that can even be purchased at grocery stores.
If a certain amount of dirty air passes through both, the number of “unclogged” pores will be greater in a thicker filter than in a thinner one. A deeper depth can also improve the life and efficiency of the filter; they also make it easier for air to enter and exit the filter. The MERV (Minimum Efficiency Reporting Value) is a rating that indicates how well an air cleaner can accumulate particles in the air in your home. Therefore, if it is absolutely necessary to install these thicker filters on a return grille, I recommend that you close the return duct tightly and be airtight.
Most HVAC technicians recommend changing 1-inch air filters every 30 days, while 4-inch filters can be changed every 3 to 6 months. And that brings us to a head-to-head comparison between a 1-inch and 4-inch oven filter before selecting the next filter replacement. These media filters have much stiffer cardboard frames, and some media filters even have plastic “rails” on the top and bottom so you can slide them inside the oven with a very tight seal. If you have an oven in your house, the clogged filter might bother you every 2 to 6 months and ask for a new replacement.
The pleats of the 4-inch filter are large, indicating its larger surface area for trapping and filtering contaminant particles. For example, since you'll be replacing 1-inch filters with a MERV height more frequently than 4-inch filters (see the maintenance section above), you could save money with a 4-inch filter, depending on the MERV you get. Let's get straight to the point: the 4-inch oven filter will provide you with better indoor air quality. For comparison, a 4-inch thick filter will have approximately twice as many surface areas as a 2-inch thick filter.
That said, the 1-inch filter may be too shallow, causing a loose fit that allows unfiltered air to enter the ducts. For example, if you have pets or live in an area with a lot of surrounding traffic, you'll change your oven filter more often.