We are running them at colder temperatures at higher voltages, the bitmain power supplies are very temperamental to voltage. If you run one at 120 volts you will be pulling 1400 watts, which is not a good idea. The power supplies get more efficient at higher voltages, and the fans work less when its colder.
The bitmain power supplies are very temperamental period. Many refuse to start a miner if the temp is below about 50F. That is not the point. Your claiming your S9 miners are running at about 20% higher efficiency than every other S9 miner on the planet. Please explain in detail how you are accomplishing this.