The City of Toronto has been undertaking retrofit projects to refurbish an aging building stock and increase performance in multi-unit residential buildings (MURBs). These retrofit considerations include solutions proposed for balconies, a common weak point in the building structure. A balcony enclosure retrofit was one such solution, using overcladding to insulate the exposed balcony slab and parapet, enclosing the open portion of the balcony with glazing. The effect of the balcony enclosure differed depending on the balcony type, varying with characteristics such as balcony to façade ratio, orientation and the projection type of the balcony, whether inset or projecting. When models were retrofit with balcony enclosures, results showed an overall decrease in energy use as the enclosures raised internal air temperatures, lowering demand for heating. The balcony characteristics which showed the largest decrease in energy use when retrofit with balcony enclosures were inset balconies with high balcony to façade ratio.