A clogged filter makes your heating and cooling work harder. It's a five-minute job most people forget for months.
Difficulty: Easy. Plan on 5 min.
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Turn the system off at the thermostat.
Find the filter slot at the furnace or air handler, or behind a return-air grille.
Slide out the old filter and read the size printed on its frame.
Insert the new filter with the airflow arrow pointing toward the furnace.
Turn the system back on. Write the date on the filter frame so you know when to change it next.
Nice work. A new fix shows up every day, and the Fix Ladder has step-by-step guides for common home repairs.