Out of curiosity what is controlling the fans now. You indicated they are controled by humidity and temperature so they do have some smarts to them.
Are they home exhast fans, or simply for atic circulation of air? Is the humidity reading from with your home, simply about your attic, or does it do some kind of check of inside and outside? If they are exhast fans do you try to open the windows when it is running to help it cycle air through the house better?
