The CB series of combination boilers from Noritz is a year-round whole-home solution that utilizes high-efficiency condensing technology to deliver hot water to both plumbing and hydronic heating applications, including those in colder climates. The CB combi performs at a 95% AFUE, meaning 95% of the Btu/hr. input is converted into usable heat. The fuel-saving performance meets Energy Star Most Efficient standards.