This paper describes yearly and monthly optimization of greenhouse shells. Simulations adopt a validated building energy simulation program, adapted and re-validated for simulation of commercial greenhouses, including a tomato crop model. The work focuses on multi-objective optimization of thermal and optical greenhouse shell properties using a genetic algorithm. Analysis of optimization results is supported by sensitivity analyses. The paper concludes that monthly
adaptation of greenhouse shells provides little improvement in the crop production and energy performance of the greenhouse when compared to the yearly optimized greenhouse. In the case of adaptable shells, however, high-performance low-energy greenhouses can be achieved at a relatively low level of complexity
