# Performance of Solar Control Films on Building Glazing: A Literature Review
## 3 Solar Control Films
### Impact of Solar Control Films on the Main Thermal and Solar Optical Properties of Clear Glass  
The performance of SCFs depends on their thermal and solar optical properties, as well as on the properties of the glass substrate to which they have been applied to, as referred in EN 15755-1 [33]. It is important to highlight that there are limitations when SCFs are applied to specific types of glazing due to potential thermal shock breakage of the glass substrate that is usually promoted by the increasing solar absorptance by the film. As a result, a careful analysis should be carried out prior to applying SCFs. The impact of different types of SCFs on the main thermal and solar optical properties of two glass substrates representative of common building glazing solutions (clear single and double glazing) is assessed in the present section. The selected glass substrates (Table 1) are composed of clear glass panes with a thickness of 6 mm and a gas filling chamber with 16 mm of thickness in the case of the double-glazing solution. The SCFs previously assembled were considered for the impact assessment conducted in this section. The ranges of values of the main thermal and solar optical properties of the clear glazing solutions with and without different types of SCFs presented in this section were computed through Optics [29] and Window [30] software. Figure 5: Ranges of values of the thermal and solar optical properties of glass and SCF systems, considering SCF is present in the IGDB database [31] when applied to the internal (**a**) and external (**b**) surface of a clear single glass (6 mm). Figure 6a shows the ranges of values of the main thermal and solar optical properties of clear single-glazing, with and without different types of SCFs applied to the external glass surface. All types of SCFs made it possible to reduce the solar and visible transmittance values of the glazing, particularly reflective and dual reflective films (by up to 94%). The visible reflectance values increased (up to \(\tau_{v}=0.63\)) in the presence of all types of SCFs. Low-E films drastically reduce the emissivity (lowest \(\varepsilon\) of 0.05) of the glazing and, consequently, the thermal transmittance coefficient (down to U = 3.26 W/(m\({}^{2}\cdot\)K), equivalent to a reduction of 44%) of the window. Figure 6b shows the ranges of values of the main thermal and solar optical properties of clear single-glazing, with and without different types of SCFs applied to the external glass surface. The types of SCFs with external applications are more restricted than those available for internal applications. The ranges of values of the properties tend to be shorter and tend to include lower values in the presence of SCFs with external application, when compared with SCFs with internal application. However, this could be explained by the scarce number of SCFs with external application considered in this study. The main properties of the safety and protection SCFs are similar when comparing internal versus external application. The thermal transmittance coefficient remained unchanged with the application of external SCFs. Figure 7a shows the ranges of the main thermal and solar optical properties values of clear double glazing with and without different types of SCFs applied to the internal glass surface. SCFs modified the values of the properties of the double-glazing in a similar way to that previously observed with the single-glazing (solar and visible transmittance reduced by 94%). However, the application of SCFs to double-glazing did not result in significant reductions in the solar factor (lowest g of 0.31, equivalent to a reduction of 59%) and the