Which way should the arrow point on furnace air filter?
The arrow on a furnace air filter should point in the direction of the air flow. Since a filter is designed to clean the air before it reaches the blower on a furnace or A/C unit, the arrow should point toward the system.Finding Your FilterMost forced air heating and cooling systems have filters in or immediately adjacent to the furnace. Some filters are behind grills of air return ducts in hallways or ceilings.Identifying the Air ReturnIf you are unsure which direction the air flows within your system, remove the old filter and look to see which side is the dirtiest. The air is coming from that direction. The arrow on the new filter therefore should point in the direction of the cleaner side of the old filter.Still Not Sure?Turn on your fan at the thermostat. Remove the filter. Hold a large piece of paper in the slot where the filter usually sits and observe the direction it bends. That is the direction in which the arrow should point.If You Get It WrongDon’t worry, if you place a new