and install a PVC backerboard to the house. I flash this board and pre-drill a hole through it to allow the vent hood to sit flush to the board, thus preventing large gaps. FAN NOISE When selecting a vent fan, con- sider how much noise they make. Bathroom exhaust fans measure noise in sones. Rather than a 4-6 sone bath- room fan, look for one that’s close to or at a 1. 5 sone rating—a much quieter fan. You may have to put up with some noise for a more powerful fan, depending on the fan’s size and pipe run layout. Most fan labels have Home Ventilating Institute (HVI) ratings so you can compare noise and energy efficiency. Choose the quietest, most energy-efficient fan that will do the job for you. There are many quality brands: Nutone, Panasonic, Ventech, and Broan. I suggest choosing Attach the mounting plate for the vent hood. Then install the vent hood and seal it to the house exterior. The vent duct shown runs along the wall to a corner of the home.
Seal all joints in the pipe, elbow and connection seams with aluminum tape (not standard duct tape).
When possible, use smooth, solid aluminum duct. Ribbed plastic duct can develop dips where moisture can condense and pool, and eventually cause odors or leak into the ceiling below. Over time the flexible plastic can also become brittle and crack, so the solid aluminum duct is a better quality material.
Smooth, solid aluminum duct has less air resistance than the ribbed plas- tic duct.
Install the duct with the seams facing upward and with a slight slope toward the exterior vent hood. In unconditioned attics or crawlspaces, insulate the duct.
Bathroom vent ducts must always terminate on the outside of the house.
Vent to the outside of the house using a backdraft-protected hood.
DUCT INSTALLATION TIPS