In regions with warm and hot climates as is the case of several countries of the Mediterranean basin, it is interesting to study the energy balance inside a greenhouse and to quantify the heat transfers along the building components (roof, walls and ground) in winter and during night time. The present experimental work was conducted in an unheated glasshouse without crop in the region of Batna, Algeria. Three types of measurements were done from January to March: the first one is at a cloudy night; the second one at a windy night and the third one at a cloudless night. The results indicate that the greenhouse ground is considered as a significant heat source which can compensate the energy losses through the walls especially during a night preceded by a significant diurnal insulation. In addition, the convection heat transfer coefficients inside and outside the greenhouse were estimated and analysed. A good agreement with the models reported in the literature was found.