The I-Series boiler from Rinnai America is designed for the residential market. The boiler has the ability for simultaneous usage of home heating and domestic hot-water production. The technology also includes an innovative bypass servo valve, which enables precise control of the hot-water temperature. The I-Series is available in both combi and heat-only models and comes standard with multizone heating control. 800-621-9419; www.rinnai.us.