EF-ON Inc. operates as an energy service company in Japan. It is involved in the energy-saving support service business, which includes improvement of boiler and hot water supply equipment, compressors, refrigerators, air conditioning equipment, lighting equipment, and other equipment; and biomass power generation business. The company was formerly known as The First Energy Service Company Limited and changed its name to EF-ON Inc. in October 2016. EF-ON Inc. was incorporated in 1997 and is headquartered in Tokyo, Japan.