The QuietCool Pro Attic Fan has a permanent split capacitor motor and is designed for larger attics.
This unit comes with an adjustable thermostat that allows the homeowner to kick on the fan when temperatures reach a certain a degree.
Not only is the pro attic fan effective, it saves homeowners on their A/C related costs all throughout the year.

AFG Pro 3.0 Professional Attic Fan
Airflow: 2,860 CFM
Energy Efficiency: 205 Watts @ 14 CFM/Watt
Motor Voltage: 120 VAC, 60 Hz
Energy Use: Hi: 205 Watts / Lo: 157 Watts
# of Speeds: 2