A.O. Smith continues to lead the way in residential and commercial water heating with close to 70 years of innovative hot water solutions. The ATI-240H-P is A.O. Smith's high efficiency, Ultra-Low NOx indoor model, it keeps emissions low by featuring the latest in water heating technology. Switching on when a hot water tap is opened, a built in temperature sensor helps to maintain hot water within a one degree set point during use, and the system automatically shuts off when the tap is closed saving you energy. The ATI-H line utilizes condensing technology to provide higher Uniform Energy Factors and reduce your fuel costs. An on board controller gives you simple and complete control over your water heater.