Greenhouses in northern climates require a large amount of supplemental heating for growing crops in winter seasons, so energy-efficient design of greenhouses based on local climate is important to minimize the heating demand. In this study, greenhouse design parameters including shape, orientation, the angle of the roof, and width of the span have been studied for the conceptual design of conventional greenhouses for Canadian Prairies using a heating simulation model. Five different shapes of greenhouses including even-span, uneven-span, modified arch, vinery, and quonset shape have been selected for the study. The simulation results proved that the uneven-span gable roof shape receives the highest solar radiation, whereas the quonset shape receives the lowest solar radiation. However, the quonset shape greenhouse requires about 7.6% less annual heating as compared to the gable roof greenhouse, but the quonset would not be adopted as multispan greenhouses. Therefore, the gable roof greenhouse is considered as energy efficient for the multispan gutter connected greenhouses whereas quonset shape as a free-standing single-span greenhouses. In high northern latitudes, the greenhouse with east-west orientation is more energy efficient from heating and cooling point of view when the length-width ratio of the greenhouse is more than 1. The heating energy saving potential of the large span width in single-span greenhouses is relatively higher as compared to the multispan greenhouses.