Recently, a research team led by Associate Researcher Wang Wei from the School of Architecture, SEU, in collaboration with multiple institutions including the School of Electrical Engineering, SEU, and the Lawrence Berkeley National Laboratory (LBNL), published a paper entitled “Optimal cover designs for outdoor units of air conditioners: A pathway to alleviate the hidden energy burden in Asian megacities” in The Innovation Energy, a renowned international journal underCellPress. The study systematically reveals the negative impacts of outdoor unit covers on building energy consumption and operational performance. It further demonstrates that optimized structural designs can effectively balance aesthetic requirements with energy efficiency, providing important scientific insights for urban building fa?ade design and energy-saving policy formulation.
The accelerated global urbanization exacerbates urban heat island effects and cooling-related energy consumption. The Central Urban Work Conference held in 2025 clearly stated that, for the present and foreseeable future, China should aim to "build modern and people-centered cities that are innovative, livable, beautiful, resilient, civilized, and smart," and identified"building green and low-carbon beautiful cities" and "building safe, reliable, and resilient cities" as key priorities. In response, the research team has continuously conducted urban building performance investigations, focusing on addressing deficiencies in building performance through data science, building physics, and architectural design approaches. In the context of urban renewal and fa?ade renovation, the team carried out comprehensive surveys on the design and installation of air-conditioner outdoor units in more than 80 cities across China, as well as in overseas cities including New York, London, Bath,severalcities in Sweden and Finland, Kyoto, Tokyo, Osaka, Nagoya, and Singapore. A common phenomenon was identified, that is, while buildingfacades are often newly renovated, air-conditioner outdoor units are "skillfully" concealed. This practice has become widespread alongside rapid urbanization, particularly in Asian cities. However, existing designs for outdoor unit covers primarily emphasize visual appearance and urban form control, while largely neglecting their impacts on air-conditioning system performance. As a result, energy consumption increases significantly, cooling times are prolonged, and the burden on power grids is exacerbated, especially during extreme heat events. At present, systematic studies on the relationship between outdoor unit cover structures and energy consumption remain limited, resulting in insufficient design guidelines and policy recommendations.
The research team adopted an integrated methodology combining laboratory experiments, thermodynamic modeling, and full-scale building energy simulations to systematically evaluate the impacts of air-conditioner outdoor unit covers with different structural parameters—specifically louver angles and perforated-plate porosity—on cooling/heating performance, operating duration, and overall building energy consumption. The study covered multiple climate zones across Asia and incorporated geographic information system (GIS) analysis to assess regional energy impacts. The results show that fully enclosed outdoor unit covers increase building cooling energy consumption by an average of 11.4 kWh/m2, reaching up to 26.6 kWh/m2 in extreme cases. Such enclosures also significantly prolong cooling operation time, exacerbating thermal discomfort for occupants and stress on power grids, particularly during extreme heat events. Further analysis reveals that energy efficiency losses can be almost eliminated through optimized structural design of outdoor unit covers. Specifically, louver angles of 60° or 80°, or perforated-plate porosities of 30% or 40%, reduce the increase in cooling energy consumption to nearly zero, while preserving the visual integrity of building fa?ades. In hot Asian climates—such as India and Saudi Arabia—designs featuring 80° louvers or 40% porosity are especially effective. Based on these findings, the study recommends that, where the use of outdoor unit enclosures is unavoidable, the above optimized parameters should be prioritized and incorporated into building fa?ade design guidelines and energy efficiency standards. This work represents the first systematic quantification of the energy impacts of air-conditioner outdoor unit enclosures across Asia and provides clear, actionable design guidance for urban managers, architects, and policymakers. The results support efforts to enhance urban aesthetics while safeguarding building energy efficiency and power grid stability, contributing to the transition of Asian megacities toward low-carbon and sustainable development.
School of Architecture, SEU serve as the first authors with Prof. Hu Qinran from the School of Electrical Engineering and Associate Researcher Wang Wei from the School of Architecture, SEU being the corresponding authors. This research was supported by multiple grants from the National Natural Science Foundation of China, including a Key Project subtask (Grant No. 52394223) and a Young Scientists Fund (Grant No. 52208011). The work also acknowledges the strong support of Gree Electric Appliances, Inc., and Gree Electric Appliances (Wuhu) Co., Ltd.
Paper link: https://www.the-innovation.org/article/doi/10.59717/j.xinn-energy.2026.100136
Source: School of Architecture, SEU
Translated by: Melody Zhang
Proofread by: Gao Min
Edited by: Leah Li
