The a AFG SMT-3.0 is a smart attic fan that has a built-in thermostat/humidistat plus a ten-variable speed motor. Once the attic itself reaches its hottest point, the fan will run at a 3,000 CFM setting, all while only using 140 watts. The smart attic fan will automatically cycle itself down to a lower speed as the attic begins to cool. Once the fan reaches its lowest speed, the fan will blow 1,000 CFM and only using 15 watts.