| Now that you've bought a high quality Qmark 80 cfm
bath fan, you'll find that it's quiet; 1.5 sones or less and has an
efficient, permanent lubricated motor, so it will last for a long time.
How do you install it for maximum performance and minimum noise? The
installation method, ducting and controls you choose will increase the
usability and effectiveness of a good ventilation fan.
Mount the fan to the framing in a way that
minimizes the transmission of vibration from the fan to the resonant
structure of the house. Install vibration isolators, such as rubber
biscuits, or resilient channel (used to hang drywall for sound dampening),
between the fan and framing as shown in the drawings below. If you use
rubber mounts, avoid over tightening the connection. If you use, resilient
channel, install the strips parallel to the motor shaft for maximum
effectiveness. Separate the fan box from the ceiling drywall with a
resilient material such as closed-cell foam tape or backer rod. Do not use
caulking, because it will transfer sound.
Ducting
For maximum air flow, reduce pressure losses in
the fan duct by using only smooth wall metal pipe and fittings. (Never use
plastic flex hose of any description!) Keep the duct as short as possible,
and terminate the duct outside, with a fitting designed for the purpose
(see drawings above). Seal the joints in the ducting with metal foil tape
or fiberglass mesh and duct mastic. Do not use gray cloth duct tape!
Fasten all joints with at least 3 sheet metal screws. The air in theses
ducts often carries lots of moisture that can condense on the cold walls
of the duct. Prevent condensation from forming in the duct by insulating
the duct and wrapping it with R-11 fiberglass batts, if it protrudes above
the ceiling insulation. If the duct is a horizontal run, slope it so it
will drain outside at the termination cap. Do not use an ordinary roof
jack for a fan duct termination, because the screen will clog with lint
and it cannot be cleaned.
Controls
There are basically 3 control possibilities:
- Give the fan its own switch. If your sound
isolation job is successful, you may want to use a pilot light so you
can tell if the fan is on or not.
- Wire the fan to the bathroom light. This
guarantees that the fan will be used when needed.
- Install either a twist timer or a programmable
timer to operate the fan at times of the day you select. A
programmable timer should have an override switch located in the
bathroom so that fan can be turned on during off program times.
Back To Bathroom
Fan Information
|
