Finding Cash in Your Dryer Vent!

by Kent Warden

Looking for ways to save money these days?  I have a suggestion that you probably haven’t thought of.  It’s in your clothes dryer vent!  Wherever it is located in your house, your clothes dryer uses energy to dry your clothes.  There are three main components to your clothes dryer: a heater that heats the air entering the dryer, a fan that pulls the heated air through the dryer, and the clothes drum that tumbles the clothes through the heated air.  The manufacturer designed these components to work together. The heater is sized to heat the air moved by the blower, and the blower moves enough air to dry the drum full of clothes.  The variable that no manufacturer can completely design for is the vent pipe in your home.  Vents come in many different configurations and materials.  Most are at least four inches in diameter, the minimum required by dryer manufacturers.  Most manufacturers build dryers to handle 25 feet of four-inch vent pipe.  What most people don’t realize is that a 45-degree bend in the pipe is equivalent to using up 2.5 feet of straight pipe and a 90-degree bend is the same as using up five feet of straight pipe.  Simply put, if you have two 90-degree elbows you now can only have fifteen feet of straight pipe and still be within the manufacturer’s specifications. 

Flexalbe duct used for dryer vents can cause a number of problems.

  • Flex duct can become damaged due to birds or other animals entering from the outside. 
  • Flex duct run through attic space will fill with water due to condensation and can block off airflow.
  • Flex duct tends to collect more lint than metal pipe.
  • Flex duct can become pinched and restrict air flow.
  • Most materials flex duct is made of are flamable or at least won't contain a fire should one start.

Even with the best vent pipe, lint still reduces the airflow from the dryer.  When the airflow is reduced, the time to dry clothes increases and your cost to operate the dryer also increases.  The air blown out by a dryer contains 25-40% of the lint you clean out of the lint filter.  The air also contains all the water being removed from your clothes.  If the dryer vent is kept nice and warm this water vapor will blow right out the pipe, however; most vents are exposed to cool to cold temperatures along their way out of the house.  This causes the moisture in the air to condense in the pipe and to attract the lint in the air.  This combination will reduce the open area of the vent pipe further reducing the airflow and increasing your costs.  Periodic cleaning of the vent is the only way to keep the air flowing properly.  Depending on your vent configuration and the amount of laundry you do, efficient operation can be maintained by annual to semi annual cleanings.

Observations of a restricted dryer vent:

  • Clothes take an unusually long time to dry
  • Clothes are hotter than usual at the end of the cycle
  • Outside of dryer is unusually hot
  • Damper (or flappers) on exhaust termination doesn’t open or barely opens when dryer is on
  • Laundry room feels warmer or more humid than normal
  • Unexplained moisture stains appear in concealed dryer exhaust duct area
  • Burnt smells in laundry room


Having your dryer vent cleaned, possibly re-routed or just fitted with new steel pipe to increase air flow can save energy every time you run the laundry. 

Please give me a call at 913-593-5074 if you have any questions about this information.