A parametric study of window-to-floor ratio of three window types using dynamic simulation

The windows can be responsible for unnecessary energy consumption in a building, if incorrectly designed, shadowed or oriented. Considering an annual thermal comfort assessment of a space, if windows are over-dimensioned, they can contribute to the increase of the heating needs due to heat losses, and also to the increase of cooling needs due to over-exposure to solar radiation. When under-dimensioned, the same space may benefit from reduced heat losses through the glazing surface but does not benefit from solar radiation gains. Therefore, it is important to find the optimum design that minimizes both the heating and cooling needs. This paper presents a parametric study of window type (single, double and triple glazing), orientation and opening size, located in the city of Coimbra, Portugal. An annual and a seasonal assessment were done, in order to obtain the set of optimum values around 360º orientation.