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Heating & Cooling

Tips & Good Practices For Clothes Dryer Venting Systems

A report from the National Fire Protection Association, indicated that dryers and washing machines were involved in one out of every 22 home structure fires reported to U.S. fire departments in 2006-2010, that is a scary thought! 


The Facts


  • In 2010, an estimated 16,800 reported U.S. non-confined or confined home structure fires involving clothes dryers or washing machines resulted in 51 civilian deaths, 380 civilian injuries and $236 million in direct property damage.>Clothes dryers accounted for 92% of the fires; washing machines 4%, and washer and dryer combinations accounted for 4%.


  • Clothes dryers accounted for 92% of the fires; washing machines 4%, and washer and dryer combinations accounted for 4%.


  • The leading cause of home clothes dryer and washer fires was failure to clean (32%), followed by unclassified mechanical failure or malfunction (22%). Eight percent were caused by some type of electrical failure or malfunction.

Dryer Venting Guidelines:


  • All dryer ducting must be a minimum of 4" in diameter.  Clean, unobstructed, frictionless ducts encourage airflow efficiency, quickens drying times, adds longevity to clothing's life and reduces utility bills. 

  • Flexible transition hose between the dryer and the wall outlet should be either the foil type or the aluminum flexible duct (most preferred).  Do not use the plastic or vinyl.

  • Concealed ducting must be rigid metal (galvanized or aluminum) duct.

  • Duct joints shall be installed so that the male end of the duct points in the direction of the airflow.

  • Joints should be secured with metal tape (not duct tape).  Do not use rivets or screws in the joints or anywhere else in the duct as these will encourage lint collection. 

  • Dryer venting shall be independent of any other systems (chimneys or exhaust vents)

  • Termination of dryer venting must be to the exterior with a proper hood or roof cap equipped with a back-draft damper.  Small orifice metal screening should not be part of the hood or roof cap as this will catch lint and block the opening in a very short time.  The hood opening should point down and exhibit 12 inches of clearance between the bottom of the hood and the ground or other obstruction.

There are more guidelines that can be specific to your locality, so check with your local building department.  

Good Practices


  • Actually inspect the termination port of the dryer and the wall or roof cap.  Look for birds nest or clogged openings.  Most importantly, feel for proper exit velocity of the air leaving the vent and look at or feel the interior walls of the duct.  If you suspect clogged or partially clogged exhaust ducting, it is likely you need to have them cleaned. 

  • Dryer vent cleaning improves the safety and efficiency and depending on the venting circumstances, should be cleaned or inspected every 6-12 months. 

  • Make sure your flex transition hose is not kinked or crushed.  The space behind your dryer should be sufficient as to provide adequate room for the flex transition hose to make its bends with minimal deflection and restrictions.

  • Routine cleaning is done from the outside by sending an air-propelled "jet-snake" through the vent.  It blows air 360 degrees backwards, blasting the lint loose and blowing it outside.  The lint is caught in a special bag. 

  • Problem Cleaning is performed when an individual dryer is not drying clothes fast enough.  They disconnect and pull the dryer out, install a large blower on the vent, and blow, brush, vacuum and/or dismantle - whatever it takes to get the vent clean.

  • The use of the white vinyl flex pipe is all but completely prohibited, both by building departments and appliance manufacturers.  Some municipalities allow or do not discourage the foil covered vinyl flex but almost all appliance manufacturers insist on the use of the aluminum flexible pipe. 

  • Keep exhaust duct as straight and short as possible.  Exhaust systems longer than the manufacturer's recommendations can extend drying times, affect appliance operation and may encourage lint build-up on pipe lining.

  • When running the clothes dryer, be careful not to over-dry. Running your dryer too long not only wastes energy but can also damage your clothes.

  • Clean lint filters regularly. Cleaning the lint filters on your washer and dryer will save energy, improve performance, and minimize fire hazards.

Look in your Yellow Pages under Duct Cleaning or search the Internet.
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Posted 2015-05-15T15:38:49+0000  by Angelo_HD_CHI Angelo_HD_CHI