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1 Page 1 of 5 Does your dryer vent work? Home laundry facilities have changed dramatically in the past 60 years. A wringer washer and concrete tubs in the basement with clothes lines outdoors or hanging from the floor joists are old memories for people born before Early automatic clothes washers and dryers were also in unfinished basements near the foundation wall and existing plumbing. Dryer vents ran up and out through a basement window or the wall rim below the subfloor. Modern trends have moved the laundry to the main floor or upper floors, often away from an outside wall. Venting the dryer in these locations can be challenging. A load of wet laundry contains about a half gallon of water. The dryer must be vented to the exterior to remove this moisture from the home. Dryer performance depends on a vent that is as short and straight as possible through materials that do not restrict air flow, that do not readily collect lint, and can be cleaned easily. Choosing a good location for the laundry, the placement of the dryer and the route of the vent all play a role in the performance of the dryer and the ease of dryer vent maintenance. Dryer manufacturers know the dangers of dryer fires and label dryers with warnings about vent materials. Installation and maintenance of the

2 Page 2 of 5 dryer vent and its terminal are VERY common concerns found in home inspections. The most common adverse condition found is a loose or damaged vent. It is essential that home owners know the PATH of the dryer vent and the location of the terminal. Be aware of excess moisture conditions when the dryer is operating, and check the connection to the dryer and observe the operation of the dryer at the vent terminal. It is also important to be aware of long drying times as this indicates a potentially dangerous clogged vent. The duct must connect to a terminal that opens freely, does not restrict air flow, restricts bird nesting and does not readily clog with lint. The type of vent terminal shown at left clogs readily and is NOT recommended. Vent terminals with 4 one inch flaps work well. Hooded vents that have a full 4 inch hood depth also work. The vent terminal location should be readily accessible so that the duct can be cleaned from the exterior. The ideal dryer location is immediate adjacent to an exterior wall. Many modern dryers have multiple vent openings (bottom, back, & sides). Good home design and remodeling plans use this fact to help locate the dryer where the vent will be as short as possible. The vent should have a few elbows as possible since typical sectional elbows have the same resistance to flow as ten feet of straight vent. Unfortunately, dryer vents are not always installed by qualified professionals. Foolish mistakes in vent layout are commonplace.

3 Page 3 of 5 The vent shown above will not perform well. If the flexible connector had been shortened to about a third its length it could have made one simple bend to connect to the straight pipe instead of 270 degrees of turn. Notice the yellow warning label on the back of the dryer. This dryer probably also had a left side vent that would have permitted it to be positioned nearly tight to the wall. Vent sections should be connected with heat rated metal foil tape, not cloth duct tape which will fail from heat, and not with screws whose points project into the vent and collect lint. Many modern homes and apartments have dryer vents that extend up a wall, into an attic, and out through the roof. This configuration creates the potential for several installation errors, maintenance difficulties, and ice dams due to dryer vent induced snow melt. This type of roof terminal clogs easily and discharges warm air to the roof. A similar dryer vent has contributed to the ice buildup in the roof valley. A new vent terminal known as Dryer Jack model 486 may resolve these issues since it rises 5 above the roof and has a large cleanout cover. Available at Vents occasionally come loose from their connection to the terminal and discharge hot air, moisture, and lint into the attic. Left unrepaired, condensation in winter on the cold roof sheathing can lead to significant water damage to the sheathing.

4 Page 4 of 5 This loose dryer vent was found in summer when the attic was hot. The duct roof connection was too far away from the attic hatch to visibly confirm the status of the connection. We operated the dryer on air fluff to blow cooled indoor air into the vent and showed by infrared (IR) thermal imaging that the duct was unrepaired. The blue color in the IR image is the cooler indoor air being blown into the hot attic. Dryer vents should not penetrate the fire separation wall between a house and an attached garage, and the vent should not terminate in the garage.

5 Page 5 of 5 This dryer vent in a garage is subject to condensation, vehicle impact, and penetrates the fire separation wall. If it is to remain, it could be insulated and enclosed in a wood frame and fire rated drywall enclosure, but a better solution would be to determine an alternate path to the exterior. Dryer vent maintenance is an important home safety task. The lint screen should be checked with each dryer load and visible lint removed. (Failure to clean, is the leading cause of residential clothes dryer fires.) Check the vent terminal for clogging or obstructions Look at all accessible portions of the vent for loose joints or damage. Look inside the vent frequently and have a duct cleaning firm remove excess lint. Move the dryer or change the vent if longer than manufacturer s guidelines. (Typically 25 feet or less) If the dryer vents to the roof, check the vent in the attic and the roof terminal. Do not ignore high moisture conditions or excess lint buildup in the laundry. (These are signs of disconnected or damaged vents.) Consider installing a dryer vent safety alarm.