EF-ON Inc. operates as an energy service company in Japan. The company operates through Energy Conservation Support Service Business and Green Energy Business segments. The company is also involved in the electricity retail and forestry business. It offers, products such as boiler and hot water supply equipment, compressors, refrigerators, air conditioning equipment, lighting equipment, and other equipment. The company maintains and operates forest, as well as generates electricity from unused wood and construction waste, and supplies. It was formerly known as The First Energy Service Company Limited and changed its name to EF-ON Inc. in October 2016. The company was incorporated in 1997 and is headquartered in Tokyo, Japan.