Consumers get two solutions in one with this on-demand boiler serving up domestic hot water and space heating from one unit. The Noritz Combination Boiler is a year-round, whole-home solution that delivers hot water to both plumbing and hydronic heating applications. This means having one unit doing the work of two — and more resourcefully at that. The unit performs at a 95 percent AFUE (Annual Fuel Utilization Efficiency); that is, 95 percent of the fuel consumed goes to hea