Patent ID: 8669503

Claim:
A method of controlling application of an ac power signal to a warm window system comprising: providing a first pane of glass and a second pain of glass, wherein said first pane and said second pane are arranged substantially parallel and substantially coextensive with each other to form an interior between said first pane and said second pane; providing a first conductive layer disposed on said first pane of glass in said warm window system; providing a second conductive layer disposed on said second pane of glass in said warm window system; connecting said first conductive layer to said second conductive layer disposed on a second pane of glass of said warm window system; connecting said second conductive layer to a control terminal on a relay that controls activation of power terminals on said relay; connecting said ac power signal to said power terminals; generating a dc voltage signal whenever a controller detects that said ac power signal is to be applied to said warm window system; applying said dc signal to said first conductive layer disposed on said first pane of glass of said warm window system to complete a circuit through said first conductive layer when said first pane of glass is not broken and said second conductive layer when said second pane of glass is not broken, so that said dc signal is applied to said control terminals on said relay to activate said relay and cause said ac power signal to be applied to said warm window system.