Abstract To increase the efficiency of thermal power plants, we have recently proposed and analyzed a novel exhaust heat recovery process called hot air recirculation (HAR), applied to a brown-coal-fired power unit as a test case. However, the performance of HAR, applied to a hard coal-fired power unit, is not clearly understood yet. In this study, the HAR process was redesigned to match the actual supply air and flue gas layout of a hard-coal-fired boiler. The thermo- and techno-economic performances of HAR, as well as the conventional bypass flue (CBF) process, applied to a 600 MW hard-coal-fired power unit, were analyzed in detail. The results indicate that, when the boiler exhaust heat is recovered from 122 to 90 °C, the net coal savings, initial capital cost, and payoff period of HAR are 3.49 g/(kW·h), $1.473 million, and 1.34 years, respectively, whereas those of CBF are 2.98 g/(kW·h), $2.528 million, and 3.04 years, respectively. Therefore, it is established that HAR can benefit a hard-coal-fired power plant with a greater saving on coal consumption and a more economical project investment, in addition to providing a safe and reliable operation, as compared to similar processes.