Heating Tips

Changing Furnace Filters: The Homeowner’s Guide to the How

Homeowners understand how good care may help extend the life of a furnace, but did they know that they can change their furnace filters on their own with less than four hours, a few bucks, and some basic hand tools — no need for specialists!

Stage One: Take Out the Old Furnace Filter

Stage One: Take Out the Old Furnace Filter

Before Examining or Changing the Filter, Turn Off Your Furnace

Set the thermostat on the furnace to “off.” This will keep the furnace from starting up while you check or replace the filter.

If the furnace is turned on without a filter, it can suck up potentially-damaging loose material.

For exact directions on how to replace the filter, consult the owner’s handbook for your furnace.

Remove the Door Panel From Your Furnace by Opening or Sliding It Open

Your furnace will have a door that either swings open or slides off. To get access to the inside of your furnace, open or remove the door.

If your door falls off, you can usually remove it by simply raising it up until it comes free and then setting it aside.

Find your furnace’s filter and eliminate any coverings that are on top of it.

Typically, the filter is situated near the air return duct or the entrance to the blower chamber. You may have to remove another cover over the filter from time to time.

Locate the filter at the air return duct or the entrance to the blower chamber by looking for the vents where the air enters the furnace system.

Remove the Old Filter and Place It in Front of the Light

Pull the filter out gently with both hands for examination. Hold it up to a light to see how filthy it is and if it is time to replace it.

If you encounter any resistance when attempting to slide the filter out, it is possible that a locking mechanism is keeping it in place. Examine the system for such a system and slide the lock out of the way to release the filter.

If You Can’t See Through the Filter, Replace It With a Fresh One

When no light shows through the filter when held up to a light source, it’s time to replace it. It is critical to change the filter on a regular basis in order to maintain proper airflow through the furnace and protect it from overheating.

A cardboard frame surrounds disposable filters. If your filter has a plastic or metal frame, it is a reusable filter that you may clean rather than replacing it entirely.

Stage Two: The New Furnace Filter

Stage Two: The New Furnace Filter

Look For the Measurements on the Cardboard Frame of the Old Filter

The size of the filter will be printed somewhere on the disposable filter’s frame. Make a note of it so you may refer to it while shopping for a new filter.

Purchase a New Filter That Is the Proper Size

To get a new filter, go to a hardware store or a home improvement center. Check the measurements of the old filter and get a filter that is the same size.

Look For an Arrow on the Filter That Indicates Which Direction It Should Be Pointed

Your new filter will have an arrow indicating which direction the air travels through it. To identify which way to slip the filter into your furnace, look for this arrow.

Replace Any Covers That Go Over the Filter and Slide It Into Place

Insert the replacement filter so that the arrow points toward the furnace’s blower motor. If you removed a filter cover to remove the filter, snap it back into place.

Close or Replace the Furnace’s Door Panel

Close the furnace’s access door, or reinstall it if you removed it. Your furnace is now operational for at least another month.

Restart Your Furnace

Now that you’ve replaced the filter, return the furnace’s thermostat to the “on” setting. The filter will keep loose material out of your furnace, allowing it to function normally.

Make a note of when you replaced the filter to remind yourself to check it again in a month.