Why Does My Clothes Dryer Vent Tube Keep Clogging?
On more than one occasion, in the course of performing a home inspection, I’ll ask the homeowner if they’re having trouble with their clothes dryer and if it seems to take very long to dry their clothes. Most of the time they look astonished and ask me how I could possibly know that. I’m told that the dryer started out fine then just seemed to take longer and longer to completely dry the clothes, and they’re on the brink of calling a technician or buying a new appliance. Then I take them outside and show them the dangerous condition that exists and the cause of the problem… a dryer vent tube that is completely clogged with lint at the exhaust hood.
Not only does this condition prevent the appliance from drying properly, it’s a severe fire hazard. Then I show them the reason for the clog – a screen installed on the end of the exhaust hood. “This screen is not supposed to be there”, I tell them, “and not only is it a fire hazard, but it’s against building code”. To make matters worse, they tell me they previously brought up the issue with their builder, and was told that the screen is needed to keep “critters” from entering. What a completely incorrect statement. A properly installed vent will have a flap (damper) on the end that opens when the dryer is operating and closes when it’s off. This prevents any critter entry.
Having a screen, of any type, on the end of the vent tube is good for only one thing… stopping lint from venting and causing a clog in the entire tube, period”. Anyone who states otherwise is ignorant to the potential hazard as well as the building code. The IRC (International Residential Code) is very specific regarding the installation of clothes dryer vents and states “dryer exhaust ducts for clothes dryers shall terminate on the outside of the building and shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination. Ducts shall not be connected or installed with sheet metal screws or other fasteners that will obstruct the flow. Clothes dryer exhaust ducts shall not be connected to a gas vent connector, gas vent or chimney. Clothes dryer exhaust ducts shall not extend into or through ducts or plenums.”
There are others that are just as ignorant to the code requirements. On a recent stucco inspection, I happened to notice a severely clogged vent hood. I asked the homeowner my standard question about their dryer and was told that the tube clogged regularly. They had it cleaned out twice before, and were getting ready to have it done a third time. The company they used never mentioned the screen on the end of the tube. I’d like to think it was just an oversight and not conveniently overlooked for job security.
I also noticed my neighbors’ newly installed roof with a brand spanking new vent hood installed. Needless to say it was the wrong type and should never have been used for a clothes dryer vent. And guess what, it was already starting to clog and the roofing company would not repair it.
The Consumer Products Safety Commission estimates there are 24,000 clothes dryer fires each year in the United States, amounting to $96,000,000 in estimated property damage. Lack of maintenance and improper installations are the leading causes, and LINT is the leading material to ignite. These fires can also be caused by failure of mechanical and/or electrical parts within the dryer itself, improper materials being put into the dryer, and insufficient airflow as a result of improper installation.
A regular inspection of your dryer components and installation material should be performed as part of regular homeowner maintenance. Be sure to check your dryer vent and vent hose regularly for lint accumulation, and make certain there is no screen on the end of the tube. If the tube terminates on your roof, be certain to have a professional inspect the end for a screen if you’re not comfortable going on the roof.