The Green Fan Cord from Wisconsin-based fan accessory specialist Gardtec, is claimed to be the only fan supply cable available that can thermostatically control AC fans. Available from Aerco, this patent-pending design is revolutionary to the AC fan industry and simply replaces an existing fan cable and requires no additional wiring, circuit boards, controls boxes or design changes. It is suitable for multiple fan configurations such as fan trays. Intelligent cooling systems incorporating DC fans have been commonplace for many years because the speed of a DC fan can be simply controlled by varying the supply voltage. With the Green Fan Cord the AC fan is automatically turned on and off to keep a system operating at a pre-set optimum temperature saving energy, reducing costs, minimising noise and increasing product life.