It's recommended that a household air filter be checked every thirty days and changed when it becomes blocked with dust, dander, pollen, or debris.
It is important to change an air filter because it will keep the indoor air quality high and equipment operating efficiently. When a filter becomes blocked, the heat or cold desired can't circulate in the household and the equipment can be overworked and malfunction. Keeping a clean air filter clean will save heating and cooling costs.
Step 1: Remove and Check the Old Filter
Open up the mechanical room closet and locate the air handler and furnace. Lift up on the cover to access the air filter. Using one's hands or a pliers, grab the exposed edge of the air filter, and lift up to pull the old air filter out.
Step 2: Install a Replacement Air Filter
With a replacement 16" by 25" by 1", insert it into the channel by evening lowing it and pushing it down to the bottom of the vent.
Step 3: Close the Vent
Grab the vent cover from the front side and begin to put it in place by lowering it on the back edge first and then snapping it into place on the front edge.