How to Change a Lennox Furnace Filter: A Comprehensive Guide

Changing the filter in your Lennox furnace is an essential maintenance task that can improve your home's air quality and increase the efficiency of your heating system. In this guide, we will walk you through the step-by-step process of changing the filter, including tips for efficiency and troubleshooting common issues.

Tools and Preparation

Before you start, gather the necessary tools and ensure you have a replacement filter that fits your model. Here's what you will need:

New filter - Make sure it is the correct size and type for your model. Screwdriver (if needed) - For accessing the blower compartment.

Steps to Change the Filter

1. Turn Off the Furnace

Locate your thermostat and set it to the “OFF” position.

Ensure the furnace is completely turned off to avoid any potential hazards.

2. Locate the Filter

The filter is typically located in one of two places:

In the blower compartment: Remove the access door, which may require a screwdriver.

Near the return air duct: Filters may be accessible from the side or front of the furnace.

3. Remove the Old Filter

Slide the old filter out of its slot. Be cautious as it may have accumulated dust and debris.

Measure the old filter or consult your furnace manual for size specifications (length, width, and thickness).

4. Insert the New Filter

Take your new filter and ensure it is oriented correctly, with arrows indicating the airflow direction.

Slide the new filter into the slot where the old filter was located.

5. Reassemble the Furnace

If you removed an access door, replace it securely. Ensure everything is properly closed.

6. Turn On the Furnace

Set the thermostat back to your desired temperature and turn the furnace back on.

Tips for Efficient Maintenance

1. Frequency of Change

It is generally recommended to change the filter every 1-3 months, depending on usage and the type of filter. High-efficiency filters may require more frequent changes and should be used for better air quality, provided they are compatible with your system.

2. Type of Filter

Consider using a high-efficiency filter for better air quality. Ensure that the new filter is compatible with your furnace system and does not cause any system issues.

3. Specific Model Questions and Issues

For more specific questions or troubleshooting issues, refer to your Lennox furnace manual. If you encounter any difficulties, consult a professional heating technician.

Additional Considerations

Some older Lennox furnaces have a filter rack in a U shape that hangs inside the blower compartment. This requires cutting a piece of filter media from a roll and affixing it to the rack. This can be a bit challenging if you are not familiar with the process. Alternatively, you can cut a slot in the return duct to accept a rectangular disposable filter. Ensure that the slot or rack does not allow any bypassing of the filter by air.

Properly maintaining your Lennox furnace filter can lead to energy savings, reduced wear and tear on your system, and a healthier home environment. By following these steps and tips, you can keep your Lennox furnace running efficiently and effectively.