In the present paper, the distribution of solar energy inside the uneven span solarium has been determined in terms of solar fraction on north partition wall by using Auto-CAD 2000 for New Delhi (28.5degrees latitude). This enables the prediction of its performance for passive heating. The concept has been extended to other shapes of greenhouses for cultivation of flowers during off-season. The other shapes included for study are even span, modified arch, vinery and modified IARI. They have similar floor area and height. Analysis has been made with the help of a model based on Auto-CAD 2000 for a typical day of each month of the year. It has been observed that the solar fraction plays an important role at low altitude for thermal heating of either a building or a greenhouse during winter months. It mainly depends on the shape and size of greenhouse and time of the nth day of the year. Based on the analysis it can be concluded that the modified arch shape greenhouse is suitable for thermal cooling through out the year. Uneven span shape greenhouse is most suitable for thermal cooling of living space in winter and heating in summer, in comparison to other shapes.