This study focuses on the impact of different types of glazed balconies on the energy consumption of buildings in northern climatic conditions. The starting point was a glazed balcony in a typical Finnish block of flats of the 1970s, whose impact on the energy consumption of the building was analysed with the IDA-ICE 4.6.1 software based on 156 different calculation cases. In light of the results of the sensitivity analysis, the five key factors affecting the energy engineering design of a glazed space are the integration of the space to the building's ventilation system, heat losses from the building to the balcony and from the balcony to outdoor air, the air tightness of the balcony and the absorption coefficients of its surfaces. Research has shown that higher energy savings in kilowatt hours can be achieved in a northern than a southern climate although percentage-wise savings are higher, for example, in Central Europe than in Finland. Thus, the determination of energy savings by kilowatt hour gives a better idea of the true significance of balcony glazing in a building than a percentage-wise analysis. (C) 2015 Elsevier B.V. All rights reserved.