# Performance of Solar Control Films on Building Glazing: A Literature Review
## 4 Existing Studies on the Performance of Solar Control Films
### Comfort Assessment of Glazing Systems with Solar Control Films  
A scarce number of the existing studies assess the thermal [34; 43; 46; 50; 53; 55; 57] and visual [19; 43; 46; 50; 53] comfort in the presence of SCFs installed in building glazing systems. Some studies evaluated both the indoor thermal and visual comfort, considering the same case study [43; 46; 50; 53], to help differentiate the thermal and visual impact of SCFs. Comfort assessment has been scarcely explored in real occupancy conditions using experimental data, with the majority of the studies conducting computer simulation analyses. [PERSON] et al. [34] used the predicted percentage of discomfort (PPD) values, due to the solar radiation effect and glass surface temperature, to evaluate thermal comfort in the presence of different combinations of glazing and SCFs, under a humid tropical climate (Aw [58]). The analysis and comparison, considering these different combinations of glazing and SCFs, are of high importance as background information and to help guide/predict the performance of existing scenarios. All glazing, with or without films, except for reflective glazing, showed that the PPD due to solar radiation was higher than the PPD due to the glass surface temperature. [PERSON] et al. [43; 53] evaluated the thermal and visual comfort of a reflective SCF applied to the double-glazing of an office room located in a temperate oceanic climate (Cfb [58]). Even though occupants still feel warm/hot in the office with SCF during summer, according to the computed PMV values, the reflective film made it possible to reduce the PPD values by 20-50% when compared with the office room without SCF. [PERSON] et al. [55] evaluated the thermal comfort of a building with low-E films by analyzing indoor operative temperature values, computed using a simulation model. During summer, the low-E films reduced the percentage of hours with excessive temperature levels (higher than 25 \({}^{\circ}\)C) by 5% compared with the original clear glazing. [PERSON] et al. [46; 50] assessed the thermal and visual comfort of office rooms with double-glazing with different types of SCFs, under the hot-summer Mediterranean climate (Csa [58]) of the city of Lisbon. This study evaluates indoor visual and thermal comfort under real occupancy conditions. A highly reflective solar control film was found to significantly reduce potential glare (43% of working hours with comfortable glare levels) when analyzing the computed daylight glare index values. SCFs increased the percentage of working hours within comfort levels of operative temperature by 25% compared with the original clear glazing (10% of working hours within thermal comfort). Also, in the city of Lisbon, [PERSON] et al. [19] experimentally analyzed the indoor illuminance levels and distribution on the horizontal work plane in the presence of south-oriented single-glazing with highly reflective and spectrally selective SCFs. Field experiments were conducted in a small-scale model, under clear sky conditions during summer and winter solstice. SCFs showed a better visual performance in summer, decreasing excessive illuminance levels and promoting a more extensive spatial distribution of acceptable levels of daylight availability. The lower solar altitude during winter, that increased solar radiation perpendicular to the glazing, had a negative impact on the visual performance of SCFs. A highly reflective film was found to be the best solution to provide useful illuminance levels and prevent potential flare. This study is relevant to better understand the influence of SCFs on the indoor daylight distribution under clear sky conditions. Indoor thermal comfort in the presence of a low-E SCF installed in the double-glazing system of a building located in a cold climate was assessed by [PERSON] et al. [57]. PPDvalues were reduced up to 5% in the presence of the low-E film installed in the northwest and southwest glazing.