There is a right way and a wrong way to insert a furnace filter. Slide the new air filter in with the arrow pointing toward the furnace, and you are done. Sounds easy.
Look on the new air filter for the arrow showing the direction of the air flow. Air flow→. That arrow will always point toward the furnace, and away from the cold air return duct. The support backing on the filter gives it strength against the air pushing against it.
It can be confusing. But only relying on, “Just take the old one out and put the new one in” works as long as the old one is in correctly.
Forced air furnaces work by recirculating air throughout the house home, i.e. pushing warm air in and pulling cold air out.
Incorrectly replacing the filter will decrease your furnace’s efficiency and effective because it won’t be as warm in your house costing you money.
Also, clean air filters matter because they clean the air you breathe.
When filters are clogged with the dust, dirt or animal hair, the furnace works harder to push and pull air through the system. This costs more in utility bills, estimated at 15%, and shortens the life of furnace parts.