Ar Yvonne IEONG In Leng stands at the forefront of Hong Kong's green building sector with an international perspective. She is a registered architect in both Hong Kong and Macau and holds a Class 1 Registered Architect qualification in Mainland China. She firmly believes that sustainable architectural design is key to addressing global climate change and has therefore dedicated herself to combining sustainable development with architectural aesthetics for many years. Her projects have garnered international accolades, fully demonstrating the balance between environmental sustainability and design excellence.

A Fusion of Rationality and Sensibility

Yvonne holds a Master of Architecture from the University of Michigan and a Master of Science in Sustainable and Environmental Design from The Chinese University of Hong Kong. Over the years, her design philosophy has centred on environmental sustainability, emphasising that architectural design should maximise the utilisation of natural wind and daylight. She often says that architecture must also consider ‘feng shui’, not in the traditional fortune-telling sense, but in terms of natural wind and water.

Sustainable architectural design begins with natural resource optimisation. By leveraging precise site selection and building orientation, architects maximise daylighting and passive ventilation to lower carbon footprints. While dense modern cities often require active HVAC systems to manage extreme heat loads, the strategic integration of passive and active design defines the intelligence of modern, climate-responsive architecture.

Through the BEAM Plus framework, architects can deliver resilient buildings with a reduced carbon footprint that are ecologically balanced. She believes the new generation of architects should utilise computer software to assist in climate analysis and embodied carbon evaluation of materials to enhance the application of passive design.

She stresses that environmental protection should not be a mere slogan. In facing real and ongoing climate change, persisting in green architecture practice helps build stronger resilience and create a more sustainable future for the next generation. Today, more Hong Kong developers and owners support and focus on sustainable development, driving the continuous improvement of standards across the industry.

Low carbon and Environmentally Friendly Space Regeneration

"If you look at global urbanisation today, buildings are actually a massive driver of climate change. They are responsible for about 30% to 50% of energy use and carbon emissions worldwide. But in an ultra-dense metropolis like Hong Kong, that reality is completely amplified. Buildings here consume a staggering 90% of our electricity and drive over 60% of our carbon emissions. As our community grows, we simply can't just demolish everything and rebuild—that is far too energy-intensive. The real battleground for the industry right now is retrofitting and renovating our existing building stock and interior spaces through low-carbon and environmentally friendly regeneration."

Yvonne highly values this need and has actively promoted regeneration projects under the concept of "Low-carbon and Environmentally Friendly Space Regeneration" in recent years. Representative interior renovation projects include the Hong Kong Green Building Council headquarters in 2018 and the CC Wu headquarters in 2016; these two projects received BEAM Plus Interiors Version 1.0 Platinum and Gold ratings respectively.

More recently, she participated in the interior design of Leigh & Orange Limited’s Hong Kong headquarters, the "L&O Green Hub". This project implemented comprehensive carbon reduction and healthy office design, including indoor air quality optimisation, high-efficiency energy-saving lighting, and temperature control systems, while extensively utilising eco-certified low-volatile materials. For its outstanding energy-saving and emission-reduction performance, the project achieved the highest Platinum rating under BEAM Plus Interiors Version 2.0 (Beta Version) and won multiple related awards.

Yvonne is also adept at solving the renovation challenges of existing buildings by adapting to local conditions. For example, in the renovation project of the Gateway TS in Tsing Yi several years ago, she innovatively designed a glass shell structure on the rooftop, perfectly connecting the existing building with the newly added elevator’s structure. Combined with coloured glass windows at both ends, this created a newly expanded lobby that combines natural ventilation and abundant natural light: opening the windows in winter promotes air circulation, while in the peak of summer, it effectively blocks heat and lowers the indoor temperature. This design not only significantly reduces air conditioning energy consumption during operation, but also, along with the large green walls within the lobby, brings vibrant life and modern aesthetics into the originally dull industrial building.

Embracing New Technology in a Changing Industry

Sticking to convention is not her work philosophy, especially given the numerous challenges facing the traditional construction industry. She believes that embracing new technologies is essential for the industry to truly "revitalise." Despite the heavy workload, Yvonne believes everyone should proactively learn about and adopt new technologies, such as the application of artificial intelligence (AI) at various levels; how to effectively utilise materials to reduce embodied carbon emissions for carbon-reducing design throughout the building process; and how to leverage the open AI data promoted by the government in recent years for more forward-looking simulations. The BEAM Society Limited recently launched the "iBEAM® Assessment Automated System," marking a step towards digitalisation and paperless building assessment processes. The system is continuously updated and plans to add more functions, such as calculating the embodied carbon emissions of project materials in conjunction with BIM and providing building-related training content. In the long term, the system is expected to connect with the Buildings Department's future operations, providing the local industry with an advanced and comprehensive online platform for green building environmental assessments and building approvals.

She cited: “In recent years, the government has encouraged the industry to adopt new technologies through policies, such as establishing the Digital Policy Office and the Hong Kong Building Technology Research Institute (BTRi) to promote digital government and smart city construction. The Environmental Protection Department launched the Hong Kong Environmental Database, using AI and Geographic Information Systems (GIS) to improve the efficiency of smart environmental impact assessments; the Buildings Department developed its own “Automatic Verification Tool for BIM General Building Drawings”; and the Development Bureau requires the adoption of Artificial Intelligence (AI) technology in building projects, etc. All of these have greatly helped promote the development of green buildings and smart cities. Various related professions are working hard to learn and cooperate with these developments.”

Promoting Green Building Assessment and Cultivating Green Building Talent

Yvonne is dedicated to promoting green building. Beyond her professional work in architecture, she also participates in voluntary professional work with green building organisations and The Hong Kong Institute of Architects (HKIA).

As a Director of the BEAM Society Limited, she has participated in optimising and promoting the BEAM Plus assessment, focusing particularly on green certification for interior architecture and existing space retrofits. In recent years, she has actively promoted BEAM Plus overseas to encourage more international projects to participate in the certification. She also aims to incorporate the carbon footprint of building materials into the BEAM Plus scoring system, reflecting the need for the framework to evolve alongside industry practices.

In 2014, she became the convenor of the BEAM Affiliate training and examination programme. The programme welcomes professionals, technicians, and interior designers from the architectural and real estate industries, as well as fresh graduates aspiring to gain professional qualifications. After qualified, green building practitioners can support design, construction, and operations, injecting professional capabilities into the industry. Within the BEAM Society Limited, she also actively participates in marketing and training affairs, currently serving as the Vice Chair of the Professional Development Committee. She believes that green building is a collective mission for the entire industry. Therefore, she aims to lead by example through multiple channels to help more people understand its importance. By changing daily habits through education, combined with appropriate architectural design and spatial layouts, a powerful synergistic effect can be achieved.

In addition to BEAM Society Limited, she has also actively participated in the work of the Environment and Sustainable Development Committee under the Hong Kong Institute of Architects (HKIA) for more than 20 years, now renamed as Sustainability and Carbon Neutrality Task Group, and Yvonne currently serves as the leader. In 2012, she joined the Green Label Committee of the Hong Kong Green Building Council (HKGBC) to promote "Green Building Assessment Development" to architects. She served as a director of the HKGBC from 2014-15 and as a member of the Hong Kong Environmental Campaign Committee from 2012-18. Within the HKIA, she actively enhances members' environmental knowledge and policy understanding by organising Continuing Professional Development (CPD) courses and site visits. In June, she shared Hong Kong's achievements on UNSDGs-related projects at the UIA Barcelona World Congress 2026.

Yvonne believes that engaging in diverse regional and international architectural and environmental organisations enables mutual learning and promotion. For instance, as a senior member of the Green Building and Energy Saving Professional Committee of the China Society for Urban Studies, she gains insights into green building developments in Mainland China through its annual conference and shares these experiences with fellow members.

Ultimately, Yvonne’s journey is defined by continuous learning, deep collaboration, and a passion for sharing green building knowledge. By actively championing sustainable development courses, she hopes to ignite a collective movement—reminding us all that even the smallest step can reshape our shared future.