The short answer is that a 4-inch filter will last longer and provide better air quality for your home. However, there are some cases where 1-inch and 2-inch filters can be just as efficient, depending on the MERV rating of the filter. The MERV rating is the classification that measures how well the filter blocks particles. Most HVAC professionals will tell you that thicker filters work better than the 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.
The designers designed their oven to use a precise size, and you should always choose the filter with the correct proportions. 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. But does that mean that 1-inch filters aren't good? Let's dive into the details and find the right solution for your oven. This is where having the guidance of a professional can really help ensure that your filter fits your oven properly. Since the designers thought that the 1-inch filters would work on their own, when stacked together, the oven will push air through a barely penetrable wall.
But what does poor airflow mean? If the air flow in the heating system is poor, some of the rooms in your house will not heat up properly. Generally, any HVAC system that passes air through ducts will have a filter between the wall air return vent and the oven. If you're used to using the cheaper 1-inch fiber filter that has a loose mesh, consider a 1-inch pleated air filter to keep your system even cleaner. This means that a 1-inch filter with a high MERV rating could work just as well as a 2-inch filter with the same rating. The nominal size of an oven filter is a rounded number that is best suited to the commercialization of standard filters. Your oven filter has an important job: filtering out all of the dust and dirt that stands between the oven, the air ducts and, ultimately, your lungs.
For comparison, a 4-inch thick filter will have approximately twice as many surface areas as a 2-inch thick filter. The smallest particles of dirt, dust and allergens that pass through a 1-inch fiber filter can damage expensive equipment and cause numerous health problems.
