Many existing buildings were constructed before sustainability frameworks became standard practice in the building industry. As a result, these structures often operate with inefficient energy systems, higher water consumption, and limited environmental management strategies. LEED (Leadership in Energy and Environmental Design) certification provides a structured approach to improving building performance through energy optimization, water efficiency, sustainable materials, and indoor environmental quality. Engaging experienced LEED consultants helps building owners evaluate operational performance, identify improvement opportunities, and implement upgrades aligned with certification requirements.
1. ERKE Consultancy
ERKE Consultancy, established in 2007, operates through offices in Istanbul, Dubai, and London. The firm has completed more than 200 LEED-certified projects across 15 countries, demonstrating extensive international experience in green building consultancy. ERKE’s team includes LEED Fellows, LEED APs, BREEAM Assessors, EDGE Experts, WELL APs, and product sustainability specialists.
For existing buildings, ERKE conducts comprehensive building performance evaluations, including energy modeling, water efficiency analysis, and material sustainability assessments. Their services include identifying retrofit opportunities and managing the entire LEED certification process. ERKE’s experience with large and complex buildings, such as airports, hospitals, and corporate headquarters, allows the company to deliver sustainability upgrades while maintaining building operations.
2. ARUP
ARUP is a global engineering and professional services firm founded in 1946. The company provides multidisciplinary consulting services that include engineering design, environmental advisory, and sustainability planning for buildings and infrastructure.
In existing building projects, ARUP focuses on improving energy performance, reducing emissions, and optimizing building systems. Their sustainability consulting services are often delivered alongside engineering improvements and building modernization initiatives.
3. WSP Global
WSP Global is a multinational professional services firm headquartered in Canada and operating in more than 50 countries. The company provides engineering, environmental consulting, and advisory services for a wide range of building and infrastructure projects.
For existing buildings, WSP supports clients with energy performance analysis, sustainability planning, and environmental compliance strategies. Their LEED consulting services typically accompany building retrofit and operational improvement programs.
4. Khatib & Alami
Khatib & Alami is an international engineering and architecture consultancy founded in 1959 and headquartered in Lebanon. The firm operates across the Middle East, Africa, and Europe, offering planning, design, and sustainability consulting services.
For existing buildings, Khatib & Alami supports performance improvement through energy-efficient building systems, water conservation strategies, and sustainable infrastructure planning. Their LEED consulting services are commonly integrated with architectural and engineering upgrades.
5. Ramboll
Ramboll is a Denmark-based engineering and environmental consultancy established in 1945. The firm provides technical advisory services for infrastructure, environmental projects, and building developments worldwide.
In existing building projects, Ramboll offers energy efficiency assessments, environmental impact analysis, and sustainability strategy development. These services help building owners align operational improvements with LEED certification goals.
6. Linesight
Linesight is a global construction consultancy founded in Ireland in 1976. The firm specializes in project management, cost management, and program advisory services across multiple sectors.
For existing building upgrades, Linesight supports project coordination, sustainability planning, and cost evaluation. Their involvement in LEED-related projects generally focuses on managing the implementation process and ensuring sustainability measures align with construction schedules and project budgets.
7. AtkinsRéalis
AtkinsRéalis, formerly SNC-Lavalin Group, is a Canadian-based engineering and project management consultancy with global operations. The firm provides engineering design, infrastructure consulting, and sustainability advisory services.
For existing buildings, AtkinsRéalis supports sustainability upgrades through environmental planning, energy system improvements, and facility modernization strategies. Their LEED consulting services are typically delivered as part of larger engineering and building performance improvement programs.
Summary
Enhancing sustainability in existing buildings requires technical expertise in energy performance, environmental management, and operational optimization. Several international consultancies support building owners in implementing sustainability upgrades and achieving LEED certification.
- ERKE Consultancy
- ARUP
- WSP Global
- Khatib & Alami
- Ramboll
- Linesight
- AtkinsRéalis
These consultancies offer a range of capabilities including sustainability advisory, engineering design, and project management services. The most suitable consultancy depends on project experience, building scale, operational needs, and available project budget.