Looking
for a fan that's low maintenance, low noise and low cast? A
solar-powered fan meets all three of these desires. Solar attic fan kit
-- well-suited for gable ventilation. The separate units for
collection, ventilation and control make the system versatile. The kit
includes a 40-watt solar panel, a thermostat / controller and a 12-volt
DC powered 11" diameter fan. For best results, engineer and solar
designer Jeff Gilbert suggests always selecting a solar panel with
double the output required by the fan used.
Before
beginning the installation, locate due south should (using a compass if
necessary). For this home -- with its flat pitch roof -- a flush mount
is all that's needed. After determining the installation angle, it's
time to connect the wiring to the terminal box on the underside of the
solar panel. A wiring diagram is usually printed on the underside for
easy DIY installation.
A
water-tight connector is added to the outside of the junction/terminal
box to keep moisture away from the wiring that will be added. Strip the
14-gauge wire and thread it through the junction box opening. Connect
the red (positive) wire to the positive terminal; connect the black
(negative) wire to the negative terminal. Add the water-tight lid to
the box and tighten it into place. Tighten the water-tight connector.
Use
a hammer to locate the rafters. The panel will be held securely to the
roof by Z-bracket mounts that will be drilled into the rafters. The
Z-brackets will also elevate the panel from the hot roof surface,
making it work more efficiently. Stainless steel hardware should be
used to connect the Z-brackets to the inside edges of the panel. Add
butyl sealant under each Z-bracket (Image 1) before drilling the
brackets into the roof (Image 2).
Run the electrical cable from the panel along the roofline to the end near the gable vent.
Secure the wire to the roof at 18" intervals for safety.
Run the wire through the gable vent.
With the solar panel in place, the fan is ready to be installed in the attic. Select and mark the location of the fan.
Measure and cut a 2" x 4" brace. Use a drill and screws to secure the brace within the gable opening.
Secure
the fan to the brace using wood screws (Image 1) and to the surrounding
gable area. Strip the 14-gauge cable that was fed through the opening
and connect it to the fan wires to test. (Remember to connect the
positive wires to the positive wires on the fan and negative to
negative wires.) If enough power is being generated, the fan should
start turning (Image 2). If the wires are connected backward, air will
blow into the attic instead of being removed.
If
adding a thermal switch/temperature controller, add a standard plastic
electrical box to an area near the fan. After securing it into place,
feed the cable into the box (which will house the controller) from the
solar panel. Connect one wire from the controller to the panel wiring,
and connect the other wire to the fan wiring (Image 2). Use a wire nut
to secure all together. Secure the temperature controller within the
electrical box and set a temperature that will activate the fan.