Patent ID: 8155797

Claim:
A control system for a window fan, the window fan having a fan for communicating air between an interior area having interior air and an exterior area having exterior air, comprising: an electronic controller in electrical communication with said fan; a control panel having a user selectable set point input, said set point input in electrical communication with said electronic controller and providing a user selected set point to said electronic controller; an indoor sensor located so as to be responsive to at least one characteristic of said interior air, said indoor sensor in electrical communication with said electronic controller and communicating said at least one characteristic of said interior air to said electronic controller; an outdoor sensor located so as to be responsive to at least one characteristic of said exterior air, said outdoor sensor in electrical communication with said electronic controller and communicating said at least one characteristic of said exterior air to said electronic controller; wherein said window fan is operable in an automatic mode, wherein in said automatic mode said electronic controller causes said fan to be activated when: said at least one characteristic of said interior air indicates a dry bulb temperature of said interior air is greater than said set point, said at least one characteristic of said exterior air indicates a dry bulb temperature of said exterior air is less than said dry bulb temperature of said interior air, and said at least one characteristic of said exterior air indicates a dew point of said exterior air is less than a dew point of said interior air as indicated by said at least one characteristic of said interior air; wherein said fan may be driven at variable speeds; wherein the speed of said fan corresponds to a differential between said set point and said indoor dry bulb temperature; a second fan, wherein said second fan is an exhaust fan for expelling said interior air into an exterior area and wherein said fan is an intake fan for drawing exterior air into an interior area, and wherein the speed of said second fan corresponds to a differential between said set point and said indoor dry bulb temperature; wherein said fan and said second fan may be driven at low, medium, and high speeds; and wherein said electronic controller causes said fan and said second fan to be operated at said low speed when said differential between said set point and said indoor dry bulb temperature is within a first range, wherein said electronic controller causes said fan and said second fan to be operated at said medium speed when said differential between said set point and said indoor dry bulb temperature is within a second range greater than said first range, and wherein said electronic controller causes said fan and said second fan to be operated at said high speed when said differential between said set point and said indoor dry bulb temperature is within a third range greater than said second range.