How Often Should You Clean a Gas Furnace?

Keeping your gas furnace clean will help ensure that it doesn't spread dirt, dust and other debris around your home. It will also help ensure that your home's air quality is safe and healthy and that your furnace's filter is working properly. Clean your furnace filter every three to four months and clean your furnace every year.


Your furnace filter will clean the air that it blows out of it. This ensures the furnace isn't blowing dirt, mold or other allergens into your home's air environment. Some gas furnaces require you to change the filter every few months while others will simply need you to clean it instead.

Cleaning Filters

Clean the filter by first turning off the furnace and allowing it to cool completely. Be aware that the filter will be very dirty and cover the floor and your clothes in dirt. Take the filter outside and bang it against a fence of the floor several times to knock out most of the dirt. Soak the filter in clear water and brush it with a stiff-bristled brush to remove the rest of the dirt. Rinse it thoroughly and let it dry completely.

Cleaning Furnace

You need to clean the entire furnace to ensure that the furnace is working efficiently. Dirt and debris can clog up areas in the furnace and prevent it from filtering out carbon monoxide. Carbon monoxide is also a product of inefficient burning and will occur if your gas furnace is very dirty. Clean your furnace every year to prevent this. Most gas furnace warrantees are void if you don't clean them every year.

Cleaning Steps

Turn off the furnace and let it cool completely before cleaning it. Open the access door on the furnace and clean the entire area with a stiff-bristled brush. Remove the components of the furnace and clean them each thoroughly and carefully. Be aware of how you remove them to ensure that you put them back properly. Pay special attention to cleaning the furnace. Use a vacuum to suck out all of the debris from tight spaces.