How to Replace Your Furnace Filter (Size, Type, and Frequency)

Identify your filter size by reading the frame for three numbers like 20x25x1, then verify they all fit and note the correct thickness. Choose a filter type that balances air quality with your system’s needs—higher MERV for allergies, pleated for better trapping, or fiberglass for budget, ensuring compatibility with airflow. Replace safely: power off, remove…







