This low profile window fan earned The Best rating from the Hammacher Schlemmer Institute because it produced the highest air velocity and was the most quiet. Anemometer readings showed that it produced 761 feet-per-minute air streams from 2' away at high speed, far superior to lesser models that could only muster 344 fpm from the same distance and the same speed. The fan generated only 45.2 decibels of noise, lower than a normal conversation. Its single fan draws fresh air in from the outside or can function as an exhaust and push warm air out. Remote-controlled fan speeds; thermostat can be set to automatically turn the fan on or off at preset ambient temperatures. Fits windows 26" to 40" W x 7 1/2" H x 5 1/2" D. (8 3/4 lbs.)