A clean condensing furnace was developed by using acidic gas reduction (AGR) catalysts. The AGR catalyst technology is capable of minimizing condensate acidity and NOx emissions in advanced gas furnace. In the study, different AGR catalyst materials were explored. The AGR with low Pt/Rh loading achieves an improved annual fuel utilization efficiency (AFUE) without impairing the performance in achieving neutral condensate and ultralow NOx emissions. The AGR with low Pt/Rh loading enables even better ability to convert NOx. Moreover, the low-cost AGR realizes nearly zero cold-start CO emissions, as is attractive in the battle to keep public safe from dangerous CO in furnaces.