Things You'll Need
Keep your Goodman gas furnace running efficiently first and foremost by replacing the filter on a regular basis. According to "Insulate & Weatherize," you should stay away from "permanent" filters that you wash and reuse; those filters actually tend to provide more resistance to air movement, reducing energy efficiency. Instead, go for the cardboard-framed disposable filters. Replace the filter on a Goodman furnace every month or so, especially during the hottest and coldest times of the year.
Turn off your Goodman gas furnace. Locate the filter access door, which varies by unit.
Open the access door by pulling it toward you, which will reveal the filter.
Carefully pull out the filter by hand. You may have to nudge it a bit, as it may be fitting snugly inside the unit. Be gentle so you do not rip the cardboard. Dispose of the old filter by simply throwing it into the garbage.
Vacuum any dust that has fallen onto the floor. Also try to vacuum out the filter housing on your furnace.
Slide in the replacement filter in the same position as the old filter. Close the access door, and turn on the furnace again.
Filter replacement on Goodman gas furnaces differs according to installation. Refer to your installation materials for specific instructions for your unit. Also consult the instructions accompanying the replacement filter. Ensure your filter is the correct replacement size before you begin installation.
Do not operate your furnace without a filter.