Experimental and theoretical study on the effect of window films on building energy consumption

• Comparative experiments were carried out for non-filmed and filmed glazing.
• The temperatures of the filmed glazing were higher because of the extra heat absorbed.
• Comparative study was carried out with different glazing and film materials.
• Year round performance was predicted by validated models based on HK TMY data.
• 50–80 kW h electricity saving on AC system can be predicted for 1 m2 film annually.

Solar control films are designed to absorb or reflect the incident solar radiation, in order to reduce solar transmission through window glass. In the present study, the glass surface temperatures were measured for selected solar window films on various applications, and compared to the cases of the same window glass types without solar window films. Dynamic simulation models are also developed with the aid of the building energy simulation program EnergyPlus. After experimental validations, the computer models are used to evaluate the energy saving potentials of the subject samples of solar window films as applied onto glazing of three different function rooms in Hong Kong, namely office, shopping mall and hotel guest room. The results show that the thermal performance of the film applications on clear glass is better than on tinted or laminated glass windows. Solar films have very good energy saving potential when applied to all three functional areas in commercial buildings, and the best results are found in office applications.