Homeowner Resources

Clothes Dryer Vent Safety Tips

When was the last time you had your dryer vent cleaned? Lint and debris can build up in your clothes dryer duct causing your dryer to exhaust at less than optimum efficiency. This creates potentially hazardous conditions including carbon monoxide intrusion and the possibility for fires. If a gas clothes dryer is improperly vented or the exhaust duct itself is blocked by lint or debris, carbon monoxide can be forced back into your living space.

CSIA Certified Dryer Exhaust Technician® inspects, cleans and verifies that the venting system is sized and installed correctly. For example, plastic transition ducts (joining the dryer to the wall) should be replaced with metal ducts because it is non-flammable, unlike plastic. Annual dryer exhaust vent inspections (also known as dryer exhaust duct inspections) are more necessary due to the complex construction of today’s homes. Dryers in newer homes are typically located away from outside walls in bathrooms, kitchens and in hall closets which is convenient, but potentially dangerous from a safety standpoint. These locations mean longer venting distances often installed with more bends. As a result, dryer ducts are harder to access and this additional length creates more surface area where lint can collect and animals and birds can hide.

According to the US Fire Administration, between 2002 and 2004 clothes dryers counted for about 15,600 reported structure fires, 15 deaths and 400 injuries annually. “Failure to clean” is the leading factor contributing to clothes dryer fires in residential buildings. The Chimney Safety Institute of America recommends that CSIA Certified Dryer Exhaust Technicians perform exhaust duct inspections on an annual basis to ensure efficient operation of your clothes dryer system. Certified Dryer Exhaust Technicians have passed an extensive exam on the proper inspection and maintenance of dryer vents, including applicable codes and standards relating to these systems. In addition to these safety considerations, annual clothes dryer exhaust inspections by a CSIA Certified Dryer Exhaust Technician can also increase the efficiency of your clothes dryer and decrease the wear on your appliance saving you money.

Appliance Efficiency
A clean exhaust duct prevents heat, moisture and, in the case of gas clothes dryers, carbon monoxide from being trapped in your home. When this type of spillage occurs, energy, natural resources and time are all wasted because your appliance works too hard and runs longer than necessary. Moisture can also cause damage to drywall, wallpaper, ceilings and other building materials.

Wear on Your Clothes Dryer
If your dryer takes twice as long to dry clothes as it should, the number of loads that it will dry is cut in half. When the dryer runs at higher than designed temperatures, the life of your clothes dryer decreases. This can lead to the heating element burning out or a fire could ignite as a result of overworked safety controls.


Did You Know...7 Facts About Clothes Dryer Exhaust Safety

1. According to manufacturer’s specifications and local codes, dryer ducts must be a minimum 4” in diameter and at least as large as the dryer outlet.

2. Unless otherwise specified by your dryer’s manufacturer or local code, the developed length of your dryer’s exhaust duct should not exceed 25 feet. (When determining developed length, each 90º turn adds 5 feet to the actual length.)

3. Dryer vents shall be independent of all other systems and terminate outdoors, not into a chimney, crawl space or attic.

4. Your outside dryer exhaust vent’s termination hood should be equipped with a back draft damper to ensure that the exhaust doesn’t come back in your home.

5. Metal transition ducts should be used between the dryer and the exhaust duct.

6. Flexible transition ducts should never be used in an attic, a crawl space, or inside a wall.

7. The CSIA Certified Dryer Exhaust Technician credential is the only nationally-recognized credential of its kind.


The Chimney Safety Institute of America (CSIA) is a non-profit educational institute that has established the only nationally-recognized certification program for dryer venting professionals in the United States. The program was developed in keeping with the CSIA’s commitment to the safety and efficiency of chimney and venting systems and to the elimination of residential chimney fires, carbon monoxide intrusion and other chimney and vent-related hazards. CSIA devotes its resources to educating the public, the insurance industry, chimney service professionals and other fire prevention specialists about the prevention and correction of chimney and venting system hazards.

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