I clean dryer vents and plenty of them. One of the things that often comes from this endeavor is needing to find new ways to run dryer vents when the current vent is either unsafe, or inefficient. On a recent job, I found the need for the dryer vent to exit out of a soffit was the only choice and this required some creative construction.
Soffits are basically the underside of an architectural structure, if we read the dictionary. And most of the time when a soffit is mentioned, the underside of the roof overhangs comes to mind. In this case, the home had a small addition, where part of the deck was turned into usable indoor space. It just so happens the location for the dryer duct was directly under this deck. Little thought was given to the dryer ducting once the addition was created until the dryer began to have drying issues.
As I talk often, dryers require airflow to dry the clothes and anything the slows this airflow will affect dryer performance and safety. The problem that was created for the dryer was the venting no longer exited the home horizontally, but had to make a bend and point toward the ground in order to make it around the existing structural elements of the addition. A handyman came up with a solution for the customer (photo below) which worked except for when the cage (remember we don’t cage dryer vents) became clogged with lint. The reason for the cage I surmise is the vent cover louvers only work properly when placed on a vertical surface. With gravity basically keeping them open, they were a warm doorway to any passing rodent.
The solution I created was to keep the dryer ducting running horizontal, but to have it exit into a custom sheetmetal box which allowed for a pest resistant vent cover to be installed inside. This design allowed for a reduced vent length because of the elimination of a 90 degree bend, a place which allowed for limited back pressure because most of the airflow is directed toward the ground. Plus the underside of the additions floor would remain insulated so as not to create cold spots to the foot.
All in all, I think the soffit vent solution will prove to be a very efficient and safe way to use and maintain the dryer venting. The vent cover still allows for proper maintenance and cleaning because of the box design, and should prove to be more than difficult for rodents to gain access to the dryer venting. I usually recommend to have a dryer vent exit the home most anywhere but within a soffit. But with this new design, I think this venting location can be just as good as any other on a homes exterior.