Energy saving potential and carbon dioxide (CO2) reduction potential of boiler technologies in the Korean industrial sector up to 2035 were analyzed using The Integrated MARKAL-EFOM System (TIMES) model based on bottom-up optimization. Final energy consumption by industrial indirect heating boilers in 2013 accounts for 7% of Korea's industrial energy consumption and 8% of the manufacturing sector's consumption. Energy consumption of industrial indirect heating boilers is expected to increase about 25% in the baseline scenario between 2013 and 2035. Technical potential against the baseline scenario by deploying only the most efficient technologies in new installation demand is 7.9% for energy saving and 20.7% for CO2 reduction by 2035. The most efficient technologies by boiler technology types were gas fired super boilers. Economic potential against the baseline scenario through market competition between existing and high efficient technologies is 5.6% for energy saving and 6.1% for CO2 reduction by 2035. CO2 reduction potential is higher than energy-saving potential because fuel substitution toward gas was added to the energy-saving effect due to efficiency improvement. Research and development, information disclosure, regulation, and incentives for high-efficiency boiler technologies are necessary to realize technical potential as well as economic potential in industrial indirect heating. 2017 Elsevier Ltd. All rights reserved.