Toyo Netsu Kogyo Co., Ltd.

Toyo Netsu Kogyo Co., Ltd. (known as Tonetsu) is an unlisted HVAC and sanitary systems contractor. Its defining feature is HVAC and sanitary engineering based on “Total Engineering for Air and Water,” including projects for high-demand facilities such as semiconductor plants and data centers. Founded in 1937, it designs, installs, and maintains air conditioning, ventilation, smoke-exhaust, water supply, drainage, sanitary, and fire-protection systems for office buildings, factories, hospitals, semiconductor plants, data centers, and other facilities. It is a specialized unlisted company with particular strength in HVAC and sanitary systems.