It happens so often. You take the air filter out and forget to note which way the arrow was pointed.
Does it Really Matter?
It does! There are right and wrong ways to insert an HVAC furnace filter and air return filters. If a filter is not properly installed, it could hinder the furnace efficiency and cost money.
Routinely monitor your air filters to prevent them from becoming clogged with dust, dirt or debris so they can continue filtering the air you and your family breathe. Clean air filters allow for better indoor air quality and improve the energy efficiency of your unit. When air filters are clogged, the HVAC unit has to work harder, which cuts back on the efficiency.
One way to tell when it’s time to replace filters is when you no longer can see through the filter. It is a general recommendation that you change your air filter in your home every 30 days when using less expensive fiberglass filters. High-end pleated filters can last as long as 6 months, but these standard guidelines assume average use and do not take into account the size and type of filter.
The Arrow and Air Flow Direction
To insert a new air filter correctly, look for the arrow. The arrow on the air filter should always face the unit and away from the turn air duct that carries the air that will be heated or cooled. HVAC systems push the cool air or warm air out and pull the spent air in, recirculating the air throughout your home. This means you want the used-up air that is being pulled in to flow through your air filter before being pushed back out into your home.
Still confused? A more straightforward way to figure this out is always to make the arrows face the ceiling or wall. If your filter is on the wall, the arrow should face the wall. If your filter is on the ceiling, the arrow should face the ceiling.
Nearly all filters have arrows, so if you do not see any arrows on the filter, check all sides of the filter. If there are no arrows, the side with the wireframe should be facing outward, and the side without it will be inside closer to the unit.
Eureka Moment: Once you have figured out which way the filter should go, draw the airflow direction arrow on the HVAC housing or ductwork with a permanent marker. That way, the next time you change your filter, match up the arrows’ direction, and like magic, you have changed your air filter perfectly.