DESC: Unlike ordinary single-stage (on/off, hot/cold) gas appliances the Rinnai Energy Saver has the ability to modulate both its burner and blower to provide maximum efficiency and comfort. The Energy Saver furnace incorporates an electronically driven seven-stage gas control system to help maintain an even and continuous heat output for very stable room temperature control and efficiencies in both gas and electrical consumption. The Energy Saver is attractive, quiet, compact and has a cool to the touch cabinet. All of these features add up to make the Energy Saver an excellent companion for you, in your home. Exceptional Energy Efficiency. The Energy Saver extended life stainless steel heat exchanger transfers 84% of consumed gas to useful heat.