Want to optimize the movement of hot or cool air. And why not install a quiet fan?  

Make a quiet fan directly at home to enjoy a discretion, optimal air circulation. With DC motor, these fans do agree that barely. You won't even notice when it is turned on, if not by the pleasant cool or warm air that will run optimally. 

Numerous fans are equipped with the summer/winter function, allowing both to circulate air in summer, for a temperature nice and not stuffy, but also to optimize the movement of warm air in the winter for lower costs of heating.