| Year | Detail |
| 1966 |
Wanson India starts operations in Pune. |
| 1973 |
Wanson R&D developed Multitherm, India’s first packaged water tube boiler for Indian coal. |
| 1975 |
The company gets into the water treatment business. |
| 1976 |
The company acquires Tulsi Fine Chemicals. |
| 1979 |
The company starts the Enviro division for Air Pollution Control equipment. |
| 1980 |
Wanson India becomes Thermax Pvt Ltd. |
| 1986 |
The company launches the Thermax Service Franchise Scheme. |
| 1987 |
The company introduces vapour absorption machines in collaboration with Sanyo, Japan. |
| 1989 |
The company forms the joint venture – Thermax Babcock & Wilcox Ltd. |
| 1996 |
The Energy & Environment Research Centre is inaugurated. |
| 2000 |
The company acquires boiler company, M E Engineering Ltd, in U.K. |
| 2004 |
The company opens office in China. |
| 2010 |
The company acquires European boiler maker, Danstoker. |
| 2011 |
The company Unveils Unique Solar Cooling System at MNRE’s Solar Energy Centre. |
| 2017 |
Thermax inaugurated its new manufacturing facility in Indonesia. |
| 2022 |
Thermax Bioenergy Solutions Pvt. Ltd. (TBSPL) was formed to offer bio-CNG turnkey projects. |