Can’t seem to keep your furnace air filter in place? Most furnaces feature a dedicated slot for the air filter. Located near the blower, it plays an essential role in cleaning indoor air. Conditioned air will flow through this slot before entering the ductwork. The air filter in this slot will remove dust, dander, pollen, mold and other contaminants from the air.
Even if you installed it correctly, though, the air filter may not stay in place. It may fall out of your furnace’s slot, or the air filter may get sucked into the ductwork.
Check the Size
If your furnace air filter won’t stay in place, you should check the size. Air filters are available in different sizes. The size of an air filter is represented by three numbers. The first number is the air filter’s length. The second number is the air filter’s width. The third number is the air filter’s depth. A 14X20X1 air filter, for instance, is 14 inches long, 20 inches wide and 1 inch deep.
Different furnaces support air filters of different sizes. Using the wrong size may result in your air filter falling out. If it’s too small, it will fit loosely in your furnace’s slot. The air filter may then fall out.
Consider the Static Pressure
Assuming the air filter is the right size for your furnace, it shouldn’t fall out. If it continues to fall out, negative static pressure could be to blame.
Static pressure is air resistance. If there’s too much negative static pressure in the ductwork, it may create a strong pulling force on the air filter. It will pull the air filter into the ductwork. Rather than staying in your furnace’s slot, the air filter will get pulled into the adjacent ductwork.
Change the Air Filter
Dirty air filters may not stay in place. Air filters work by catching particular matter in the air. As air flows through them, the filters will catch and hold particulate matter.
Air filters don’t last forever. The longer an air filter goes unchanged, the more debris it will contain. All of this particulate matter-based debris may then restrict the flow of air. When you turn on your furnace, the dirty air filter may move around due to all of this debris. For proper airflow, try to get into the habit of changing the air filter in your furnace once every few months.