The short answer is NO. Your thermostat is not like the accelerator pedal in your car, it is more like a light switch. It is on or off, not more or less. No matter if it is set to cool to 74 or 64, if the room temperature is 80, the system is on. No more, no less. Now some of the more elaborate systems do have more than one speed, but if your thermostat is more than 2 degrees off, the system is running as hard as it can to get it where you want it. Setting it lower will not do anything except make it run until it gets where you set it.