The Infiniti GS and GR condensing tankless water heaters feature a stainless-steel heat exchanger. With high-temperature settings, cascade operation, common venting and an optional commercial rack system, they can be installed indoors or outdoors. The Infiniti tankless water heaters have been certified by the Green Restaurant Association (GRA), the leading voice within the Green Restaurant movement. They also both meet or exceed the latest ENERGY STAR requirements and qualify for most utility rebate programs.