Go to the roof. Place the solar powered attic fan on the roof in the location that you plan to install it in. Monitor how the light of the sun falls on the fan's solar panel over the course of an average day when the sky is not overcast. Note whether shadows fall over the solar panel over the course of a day and, if they do, for how long. Review your findings at the end of the day to see whether the solar powered attic fan can be installed where it is now placed, or if it should be moved to another location.
Go into the attic. Measure six inches from the peak of the roof, across the rafter that is at your right. Drill a hole between the rafters at this measurement using a portable drill with a 8-inch drill bit. A hole cut out in the roof surrounding this hole will now allow for correct placement of the solar attic fan.
Place a mark between two rafters that is a half-foot away from the attic ceiling's peak. Measure the distance from this mark to any objects that are in the attic, for example, air conditioning or heating ducts, a fireplace chimney or stored items. Gauge whether a different placement for the fan will allow more open space between it and the objects -- allowing more air to flow freely for venting.
Look for a gable wall-mounted vent that is on one of the walls of the attic. Measure the dimensions of the grill on the front of the solar powered fan. Measure the dimensions of the vent. Compare the two to see if the cavity that will result after removing the vent will be big enough to accommodate the fan's grill. Go outside to the side of the house where the vent is located. Clock the amount of light over the course of a day that hits the vent, in order to see if enough light will strike the solar attic fan and so power the motor's blades effectively.