dryervent
My dryer's vent tube is stuffed behind the dryer and preventing it from sitting closer to flush against the wall. I found this "Periscope" dryer vent kit and was wondering if anyone had experience with these?
Do they work well? Is performance an issue at all?
International Residential Code (IRC) says the maximum exhaust duct length is 35 feet. However, it also says that this length can be overruled by the manufacturers instructions, if the instructions are provided to the inspector.
2012 International Residential Code (IRC)
Chapter 15 Exhaust Systems
Section 1502 Clothes Dryer Exhaust
M1502.4.4.1 Specified length. The maximum length of the exhaust duct shall be 35 feet (10 668 mm) from the connection to the transition duct from the dryer to the outlet terminal. Where fittings are used, the maximum length of the exhaust duct shall be reduced in accordance with Table M1502.4.4.1. The maximum length of the exhaust duct does not include the transition duct.
M1502.4.4.2 Manufacturer’s instructions. The size and maximum length of the exhaust duct shall be determined by the dryer manufacturer’s installation instructions. The code official shall be provided with a copy of the installation instructions for the make and model of the dryer at the concealment inspection. In the absence of fitting equivalent length calculations from the clothes dryer manufacturer, Table M1502.4.4.1 shall be used.
I couldn't find anything that says the termination has to be a specific height above the ground, just that it must be 3 feet in any direction from any openings into the building. And that it should have a backdraft damper, and no screens
2012 International Residential Code (IRC)
Chapter 15 Exhaust Systems
Section 1502 Clothes Dryer Exhaust
M1502.3 Duct termination. Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. If the manufacturer’s instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.
The code also says that the ducts must be 4" smooth walled ducts, and sections can't be attached using fasteners that protrude into the duct more than 1/8".
2012 International Residential Code (IRC)
Chapter 15 Exhaust Systems
Section 1502 Clothes Dryer Exhaust
M1502.4.1 Material and size. Exhaust ducts shall have a smooth interior finish and be constructed of metal having a minimum thickness of 0.0157 inches (0.3950 mm) (No. 28 gage). The duct shall be 4 inches (102 mm) nominal in diameter.
M1502.4.2 Duct installation. Exhaust ducts shall be supported at intervals not to exceed 12 feet (3658 mm) and shall be secured in place. The insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Exhaust duct joints shall be sealed in accordance with Section M1601.4.1 and shall be mechanically fastened. Ducts shall not be joined with screws or similar fasteners that protrude more than 1/8 inch (3.2 mm) into the inside of the duct.
NOTE: Always check with your local code enforcement agency before begining any project, as codes vary from location to location.
I have to wonder if the bathroom vent is really "fine" or if it's failed in some manner so that it vents out of the bathroom, into the attic (rather than out of the bathroom, through the attic and out of the wall) - that would certainly add a lot of water vapor to the attic...which would be one way to clog up the vents.
Best Answer
They work well. I find that it is best once you have the length set correctly you trim off some of the extra, bend a tab to hold the shape, and use foil tape on the inside seams and outside seams to seal them. This helps prevent leakage lint from trapping as much on the corners.