Gas Furnace Filter Airflow Direction

Air filters may have an arrow on the frame that shows you in what direction the filter should be inserted into the furnace.

Gas furnace filter airflow direction.

The arrow should always point towards the return. The arrow should always point in the direction the air is flowing. Ever wonder which way the arrow should point on your furnace air filter find out right here. If an air filter is installed in the wrong direction air will have to pass through the filter via the less porous side.

These arrows are always meant to point in the direction of the airflow. The arrow should be pointing toward the evaporator coil or toward the air handler if the filter is installed at the return grill. This will make it more difficult for your air handler to keep air flowing through the filter which will force your furnace to work harder and consume more energy to make up for the loss of airflow. But sometimes you may not know which way the air is flowing.

Here s an easy way to figure out which way the air flow arrow goes. Another way of determining the correct orientation of the filter is that the arrows always point toward the furnace itself.