In anticipation of a coming hydrogen society, Honda R&D is developing not only Fuel Cell Vehicles but also a hydrogen generation system that produces hydrogen to be used by FCVs as fuel. There are two methods of hydrogen generation we are interested in: One involves water electrolysis using electric power from solar cells and the other involves reforming methane-based city gas supplied to each residence. The Home Energy Station Phase 4 gas reforming system was developed with the concept of constructing a system similar to the anticipated future market format. To realize this concept, efforts focused on reducing the system size and cost, and this paper reports these design and verification test contents. Ongoing verification tests of this Home Energy Station system have been run at our test site at Honda R&D Americas Inc. in Los Angeles since October 2007. Since the Home Energy Station system has three functions, generating hydrogen, supplying electricity, and supplying heat (hot water), the efficiency of the system heavily depends on the demand of each load. So it is important to examine how the system operates in the real world to determine the best operating procedures and specifications of the system.