Thin film coated windows are considered as the future of fenestration market owing to their characteristic features such as solar radiation and visible light control, UV and IR rejection and promising U-value range. Within the scope of this experimental research, various thin film technologies developed for glazed areas in buildings are comprehensively analysed as a potential retrofit solution to conventional windows. 12 commercial thin film coating products are laminated between clear glass sheets with very high visible light transmittance, and they are subjected to outdoor tests covering different sky conditions. UVA/UVC blockage, visible light and solar radiation control is evaluated for a wide range of thin film coating technologies from ceramic to metallic films as well as EVA and PVB-IR. The results indicate that ceramic and metallic thin film coatings are in general successful at visible light control. 93% of incoming visible light is found to be blocked by I118. EVA welcomes about 49% of incoming solar radiation whereas it is 31% for I178. Thin film coatings are capable of rejecting almost 100% of incoming UV light. It is also achieved from the research that UVC light figures are noticeable and this justifies the ozone layer depletion which needs to be noted.