How to Replace Your AC Filter

Replacing your AC filter regularly is crucial for maintaining optimal performance, improving air quality, and extending the lifespan of your air conditioning system. A clean filter ensures efficient airflow and prevents dust, dirt, and other contaminants from circulating in your home. Here’s a step-by-step guide on how to replace your AC filter.

1. Turn Off the AC Unit

Before starting the replacement process, it’s important to turn off your AC unit to ensure safety and prevent any debris from getting into the system.


  • Thermostat: Set your thermostat to the “off” position.
  • Power Switch: If your AC unit has a dedicated power switch, turn it off as well.
  • Circuit Breaker: For additional safety, you can turn off the circuit breaker that powers the AC unit.

2. Locate the Air Filter

Air filters can be located in various places depending on the type of HVAC system you have. Common locations include:


  • Return Air Duct: Many systems have the filter located behind the return air grille.
  • Air Handler or Furnace: In some systems, the filter is located inside the air handler unit or furnace.
  • Ceiling or Wall Vents: In homes with central air conditioning, the filter might be behind a ceiling or wall vent.

3. Remove the Old Filter

Carefully remove the old filter to avoid spreading dust and debris.


  • Open the Filter Compartment: Use a screwdriver if necessary to open the compartment where the filter is housed.
  • Slide Out the Filter: Gently slide the old filter out of its slot, taking care not to knock loose any accumulated dust.

4. Inspect the Old Filter

Take a moment to inspect the old filter to determine its condition and the frequency with which you should replace it.


  • Visual Inspection: Look for dust, dirt, and other particles trapped in the filter.
  • Evaluate Replacement Frequency: If the filter is heavily soiled, you may need to replace it more frequently in the future.

5. Choose the Right Replacement Filter

Ensure you have the correct replacement filter for your AC unit. Check the size and type of filter required air conditioning repair denver.


  • Filter Size: The dimensions are usually printed on the old filter’s frame. Common sizes include 16x20x1, 20x25x1, and 16x25x1.
  • Filter Type: Choose the appropriate type based on your needs, such as standard fiberglass, pleated, or high-efficiency particulate air (HEPA) filters.
  • MERV Rating: The Minimum Efficiency Reporting Value (MERV) rating indicates the filter’s effectiveness at trapping particles. A higher MERV rating provides better filtration.

6. Install the New Filter

Proper installation is crucial for optimal performance.


  • Direction of Airflow: Ensure the new filter is oriented correctly. The filter frame usually has an arrow indicating the direction of airflow, which should match the airflow direction in your HVAC system.
  • Insert the Filter: Slide the new filter into the slot, ensuring it fits snugly and securely.

7. Secure the Filter Compartment

Once the new filter is in place, close and secure the filter compartment.


  • Replace the Cover: Put the cover back on the filter compartment and secure it with screws if necessary.
  • Double-Check Fit: Ensure the filter is properly seated and the cover is securely in place.

8. Turn the AC Unit Back On

After replacing the filter and securing the compartment, turn the AC unit back on.


  • Power Switch: Turn the AC unit’s power switch back on.
  • Circuit Breaker: If you turned off the circuit breaker, switch it back on.
  • Thermostat: Set your thermostat to the desired temperature and mode.

9. Set a Replacement Schedule

To maintain optimal performance, set a regular schedule for replacing your AC filter.


  • Monthly Check: Check the filter monthly and replace it every 1-3 months, depending on usage and air quality.
  • Seasonal Replacement: Consider replacing the filter at the beginning of each season for consistent performance.


Replacing your AC filter is a simple yet essential maintenance task that can significantly improve the efficiency and lifespan of your HVAC system. By following these steps, you can ensure your AC unit operates smoothly, providing clean and cool air throughout your home. Regular filter replacement not only enhances air quality but also helps prevent costly repairs and extend the life of your air conditioning system.

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