Electrochromic Window Film

Electrochromic Window Films (EWF) are coatings applied to windows that vary by tint. When activated by an electrical charge, EFS change the appearance and functionality of the glass. Most commercial buildings today do not have window films that can help block heat from the sun. Without a window film, the sun’s heat and its solar radiation cause room temperatures to increase. This directly impacts the ability to keep a room cool and maintain the ambient temperature of the space; therefore, impacting potential heating, ventilation, and air conditioning (HVAC) savings. This study focused on the correlation of direct light and heat on the window film to its ability to keep a space cool and maintain its temperature.   SCE estimates that there are approximately 2,984 commercial office buildings and healthcare service accounts in SCE territory accounting for approximately 9,904 GWh of annual electric energy use. Many of these commercial office buildings and health care facilities are prime candidates for EWF installation. The 2006 Commercial End Use Survey (CEUS) data indicated that commercial office buildings and healthcare facilities accounted for approximately 33% of all electric energy use consumption.   PROJECT GOAL: The lab assessment primary project goal was to compare and determine a range of EWFs’ effectiveness at blocking external solar rays to keep a space cool, while also maintaining acceptable light levels inside the space. Potential energy savings and demand reduction were not captured through this assessment. PROJECT EXPECTED OUTCOMES: Should lab testing accurately demonstrate that EWFS are capable of reducing the temperature inside a space, then the outcome of this project should be a phase 2 assessment. The phase 2 assessment should analyze the extent of the EWFS ability to reduce a spaces temperature and determine the energy savings potential based on the reduced HVAC use. Additionally, this lab assessment could help in the development of a new EFW American Society for Testing and Materials (ASTM) test standard. ALIGNMENT WITH STATEWIDE GOALS: This lab assessment aligns with several statewide goals and regulatory and policy compliance mandates including Assembly Bill 802 (AB 802) because EWFs have the potential to reduce building energy use by impacting heating, cooling, and lighting consumption.[1] PROJECT FINDINGS: This lab assessment was conducted at Southern California Edison’s (SCE) Heat Pump Water Heater (HPWH) lab, which is a controlled environment lab space located inside SCE’s Energy Education Center (EEC) in Irwindale, California. The focus of the lab testing setup was to assess EWF heat reflection properties and determine how much light is blocked by each treatment. The results show that EWF films are capable of reflecting heat. Each EWF color and mode have different performance capabilities. [1] Advancement of Electrochromic Windows, Apr 2006. PROJECT RECOMMENDATIONS: Lab test results showed that EWFs showed potential of reflecting heat from entering a space. Therefore, a second more comprehensive study is recommended to determine the potential energy savings associated with installing EWFs over standard Title 24 windows. If energy savings are exhibit and EWFs prove to be cost-effective, then an engineering deemed workpaper should be created for both ex-ante claimed savings and rebate consideration. Additionally, the development of an accredited EWF standardized test method should be considered for any future testing.