The Elite Energy Star gas water heater achieves a 0.70 EF rating thanks to a patented air intake system. Much like a turbo charger, air is pushed into the combustion chamber and creates a pressurized environment. As a result of the pressurization, tighter baffling can be incorporated into the flue design to slow down the hot gas as it travels through the water heater. More heat is transferred to the water, and less energy is wasted. Both 40- and 50-gallon units are available. 888.536.6673.