The environmental concern, ensuring comfort for occupants, pushed us to search for the impact of glazed loggia on thermal comfort of adjacent space in Cons tantine climate, having s trong climatic cons traints. An experimental s tudy is undertaken and described in this paper. Analysis of the in situ results is also discussed. This work shows that in winter glazed loggia benefit largely from solar gains. In summer, it is a thermal regulating space, delaying diurnal peak of temperature towards the end of the day. Overheating can be avoided with natural ventilation and a good use of the relation glazed loggia-adjacent space. This result leads to the possibility of retrofitting glazed loggias in hard climates, such as in Constantine (Algeria). To define criteria being able to return this addition, favourable and adapted to the winter and the aestival thermal comfort of adjacent space, a simulation is carried. But the only inves tigation is discussed in this paper.