Rinnai Corp. announced that six models from its line of tankless water heaters have earned the U.S. Department of Energy’s and Environmental Protection Agency's exclusive ENERGY STAR rating for energy efficiency, including its flagship models, the R94LS and R75LS. The company said it pioneered the process to get the ENERGY STAR designation for tankless water heaters. “Until now, water heaters were the only major residential energy end use without an ENERGY STAR designation,” said Alliance to Save Energy President Kateri Callahan.“Rinnai played an integral part in the U.S. Department of Energy’s April 2008 decision to establish an ENERGY STAR program for the category.”