The application of hill-climbing control to seek and drive the unconstrained set point of controlled variables (CVs) to their economic optimum is proposed for economic plantwide control. Its application is demonstrated on a reactor-column recycle process for energy efficiency maximization at given throughput (Mode I) and also for maximizing process throughput (Mode II). In Mode I, a one degree-of-freedom hill-climbing feedback controller on top of the regulatory layer is shown to reduce reboiler duty by 3.7% for a 25% throughput increase compared to that of a constant set point operation. Similarly, in Mode II, a one degree-of-freedom hill-climber achieves 3.0% throughput increase compared to that of a constant set point operation. These results highlight the effectiveness of hill-climbing for economic plantwide control.