A large portion of today’s building stock consists of structures developed before sustainability frameworks became widely implemented. These buildings often operate with aging infrastructure, inefficient energy systems, and limited environmental monitoring. LEED (Leadership in Energy and Environmental Design) certification provides a structured methodology to improve the sustainability performance of existing buildings by addressing energy consumption, water efficiency, indoor environmental quality, and material use. Experienced LEED consultants help building owners assess current conditions, implement targeted improvements, and guide the certification process from evaluation to documentation.
1. ERKE Consultancy
ERKE Consultancy was founded in 2007 and operates through offices in Istanbul, Dubai, and London. The company has completed more than 200 LEED-certified projects across 15 countries, ranging from Europe to the Middle East and Asia. ERKE’s team includes LEED Fellows, LEED APs, BREEAM Assessors, EDGE Experts, WELL APs, and product sustainability specialists.
For existing buildings, ERKE provides detailed performance analysis including energy modeling, water efficiency assessments, and operational sustainability evaluations. Their services include identifying retrofit opportunities, optimizing building systems, and managing the full LEED certification process. ERKE has supported complex facilities such as airports, hospitals, and corporate headquarters, demonstrating strong experience in upgrading operational buildings without disrupting daily activities.
2. ARUP
ARUP is a global engineering and consulting firm founded in 1946. The company offers multidisciplinary services including engineering design, environmental consulting, and sustainability advisory. ARUP has significant experience improving the performance of operational buildings through engineering and sustainability strategies.
For existing buildings pursuing LEED certification, ARUP focuses on energy system optimization, lifecycle performance analysis, and emissions reduction. Their sustainability consulting services are typically integrated with broader engineering modernization and infrastructure improvement programs.
3. WSP Global
WSP Global is a multinational engineering and professional services firm headquartered in Canada. Operating in more than 50 countries, the company provides engineering, environmental consulting, and sustainability advisory services for infrastructure and building developments.
In existing building projects, WSP assists clients with energy performance studies, sustainability planning, and environmental compliance strategies. Their LEED consulting services often support building retrofits and operational efficiency improvement programs.
4. Khatib & Alami
Khatib & Alami is a multidisciplinary engineering and architecture consultancy founded in 1959 and headquartered in Lebanon. The firm operates across the Middle East, Africa, and Europe and provides planning, design, and sustainability consulting services.
For existing buildings, Khatib & Alami supports sustainability upgrades through energy-efficient building systems, water conservation strategies, and sustainable infrastructure improvements. Their LEED consulting services are typically integrated with architectural and engineering enhancement projects.
5. Ramboll
Ramboll is a Denmark-based engineering and environmental consultancy established in 1945. The company provides technical advisory services across infrastructure, environmental management, and building performance optimization.
For existing buildings, Ramboll provides energy efficiency evaluations, environmental performance assessments, and sustainability strategy development. These services help building owners align operational improvements with LEED certification requirements.
6. Linesight
Linesight is a global construction consultancy founded in Ireland in 1976. The firm specializes in cost management, project management, and program advisory services for construction and infrastructure projects.
In existing building upgrades, Linesight provides project coordination, cost evaluation, and sustainability planning support. Their involvement in LEED-related projects typically focuses on implementation oversight and ensuring sustainability measures align with project timelines and budgets.
7. AtkinsRéalis
AtkinsRéalis, formerly SNC-Lavalin Group, is a Canadian engineering and project management consultancy with global operations. The firm provides design, engineering, and advisory services across infrastructure, energy, and building sectors.
For existing buildings, AtkinsRéalis supports sustainability improvements through environmental planning, energy system upgrades, and facility modernization consulting. Their LEED services are generally delivered alongside broader engineering and building performance improvement programs.
Summary
Upgrading existing buildings to improve environmental performance requires technical expertise in energy management, operational optimization, and sustainability planning. Several international consultancies provide services that help building owners implement sustainability improvements and pursue LEED certification.
- ERKE Consultancy
- ARUP
- WSP Global
- Khatib & Alami
- Ramboll
- Linesight
- AtkinsRéalis
These consultancies provide varying levels of sustainability consulting, engineering design, and project management services. The appropriate consultancy depends on project experience, building scale, operational requirements, and available project budget.