Product details:

Welcome to ultimate efficiency. With technology that operates only when hot water is needed, super-efficient heating coils, no pilot light and no storage tank to heat and reheat water, you save on energy and utility costs. In fact, Rinnai Tankless Water Heaters use up to 40% less energy than a traditional tank water heater. Plus, with premium technology, increased energy efficiency, an improved Home Energy Rating System (HERS) Index Score and optimized LEED eligibility, our tankless solutions can increase your home's value. You can even qualify for energy efficiency rebates and tax credits. It's a smart investment for now and the future.ENERGY STAR qualified.
Energy factor of .82.
Enhanced scale detection lessens possibility of serious, long-term damage to unit.
Temperature lock function prevents accidental or unauthorized changes to water temperature.