If it is not possible to install a gable fan, a roof fan is the next best choice. Wiring is simple. Follow the manufacturer's instructions for cutting the hole and attaching the fan.
About 5 hours to cut a hole in the roof, install the fan, and run cable inside an attic
Voltage tester, drill, bit, reciprocating saw or jigsaw, pry bar, utility and putty knives, screwdriver, strippers, long-nose pliers, lineman's pliers
General carpentry, splicing wires and connecting wires to terminals, installing boxes, running cable in walls and ceilings
Find power source and make sure the fan does not overload the circuit.
Roof fan, cable, roofing nails, roofing cement, wire nuts, cable clamps, electrician's tape
Once the fan is attached to the roof, wire the fan's thermostat directly to a power source. Some roof fans have a humidistat, which measures humidity, in addition to a thermostat. This runs the fan when the attic humidity is high, even if the temperature is not.