Thick air filters may seem like the best option, as they have more square feet to capture and retain air particles. But does furnace filter size really matter? To answer this question, it's important to understand the MERV rating, which is a measure of how well the filter captures particles in the size range of 0.3 to 10 microns. The higher the MERV index, the better the oven filter. However, a higher MERV filter also tends to reduce the amount of air flow.
Most air filters have their size printed on the side of the frame. The length, width and depth of the filter are measured in inches. For example, you'll say something like “16x25x1”, where 16 is the length, 25 is the width, and 1 is the depth. The oven filters should fit right inside the oven with no gaps or gaps.
If there are gaps, there is too much room for error. Knowing the environmental factors in your home and neighborhood that may affect your oven filter will help you determine how often you should change them. Look for where the return duct connects to the boiler and there should be a plate that covers the slot through which the air cleaner enters. 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. A filter that is properly adjusted together with the right thickness and density for the needs of your oven makes a difference in both the operation and maintenance of your oven. Most filters will have the size printed directly on the side of the filter in the length x width x depth format.
Basically, when you're taking measurements of an air filter, you just need to round it up to the nearest inch to find the dimensions of the filter you need to buy. When a filter that is too dense is used in an HVAC system that doesn't require that degree of resistance, it can restrict the air flow needed and cause the oven to work harder. Paying attention to changes in your home (for example, a building) and in your city (a nearby building or a large amount of pollution) will also help you decide when to replace the filter. While thickness affects overall size and surface area, density of filter fibers is another factor to consider. Dense filters tend to become covered in dust and dirt and clog faster than filters with a lower MERV rating. These 4-inch multimedia filters can have between 20 and 30 feet of surface area with their pleated (accordion) filter material. Having to bend and force the filter into the boiler is a clear indicator that it's too large.
Furnace filter sizes with a thickness or depth of one inch generally need to be changed more frequently. In conclusion, furnace filter size does matter when it comes to filtration efficiency and air flow restriction. It's important to choose an appropriate size for your furnace based on its needs and environmental factors in order to ensure optimal performance.