Switchable glass replacement windows isn't a new technology, it's been on the market for several years and has had the opportunity to be improved upon. The advancement of chemical engineering for smart glass allows improved switching methods on panes that have the manual operation. A similar improvement is in suspended particle devices where a conductive glaze covers the panes of Replacement Windows in Minneapolis MN. When denied an electrical current the elements block the light and remain opaque until a switch is tripped. When the circuit completes the particles line up and become transparent, allowing light to pass through.
Window replacement is inevitable. Replacing those old windows with new energy efficient windows can save you substantially on your heating and cooling bills. Old windows don't provide the barrier to the elements that your home needs. Your furnace and air conditioner have to work even harder to maintain the desired temperature. The harder your HVAC system works, the more you pay.