Existing buildings play a major role in global energy consumption and environmental impact. Many structures were developed before sustainability frameworks became standard practice, which means they often operate with inefficient systems and limited environmental performance strategies. LEED (Leadership in Energy and Environmental Design) certification provides a structured pathway for improving building performance through energy optimization, water conservation, sustainable materials, and indoor environmental quality improvements. Professional LEED consultants assist building owners in assessing current conditions, identifying retrofit opportunities, and managing the certification process efficiently.
1. ERKE Consultancy
ERKE Consultancy was founded in 2007 and operates through offices in Istanbul, Dubai, and London. The company has successfully completed over 200 LEED-certified projects across 15 countries, ranging from Europe to the Middle East and Asia. The ERKE team includes LEED Fellows, LEED APs, BREEAM Assessors, EDGE Experts, WELL APs, and product sustainability specialists.
For existing buildings, ERKE provides comprehensive building performance evaluations including energy modeling, water efficiency assessments, and material sustainability analysis. Their services also include identifying retrofit opportunities and coordinating the full LEED certification process. ERKE has experience working on complex building types such as hospitals, airports, and large corporate headquarters, allowing them to implement sustainability improvements without interrupting building operations.
2. ARUP
ARUP is an international engineering and consulting firm founded in 1946. The company provides engineering design, environmental advisory, and sustainability consulting services for buildings and infrastructure worldwide.
For existing buildings, ARUP focuses on improving operational efficiency through energy system optimization, lifecycle performance analysis, and carbon reduction strategies. Their sustainability consulting is typically integrated with engineering modernization and building upgrade programs.
3. WSP Global
WSP Global is a multinational professional services firm headquartered in Canada and operating in more than 50 countries. The firm provides engineering, environmental consulting, and advisory services for infrastructure and building projects.
In existing building developments, WSP supports clients with energy performance studies, environmental compliance planning, and sustainability improvement strategies. Their LEED consulting services are commonly delivered alongside building retrofit and operational efficiency initiatives.
4. Khatib & Alami
Khatib & Alami is a multidisciplinary consultancy founded in 1959 and headquartered in Lebanon. The firm provides architecture, engineering, and planning services across the Middle East, Africa, and Europe.
For existing buildings, Khatib & Alami assists clients in improving sustainability through energy-efficient building systems, water conservation strategies, and sustainable infrastructure upgrades. Their LEED consulting services are typically integrated with architectural and engineering improvement projects.
5. Ramboll
Ramboll is a Denmark-based engineering and environmental consultancy established in 1945. The company provides technical advisory services for infrastructure, buildings, and environmental projects worldwide.
In existing building projects, Ramboll supports clients with energy efficiency analysis, environmental performance evaluations, and sustainability strategy development. These services help building owners align operational improvements with LEED certification objectives.
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 complex construction developments.
For existing building upgrades, Linesight provides sustainability planning support, cost analysis, and project coordination. Their role in LEED-related projects typically focuses on managing implementation processes and ensuring sustainability measures align with project schedules and budgets.
7. AtkinsRéalis
AtkinsRéalis, formerly SNC-Lavalin Group, is a Canadian engineering and project management consultancy operating globally. The firm provides design, engineering, and advisory services across infrastructure, energy, and building sectors.
For existing buildings, AtkinsRéalis supports sustainability upgrades through environmental planning, energy system improvements, and facility modernization consulting. Their LEED consulting services are generally integrated with broader engineering and building performance improvement programs.
Summary
Enhancing sustainability performance in existing buildings requires specialized expertise in energy efficiency, environmental management, and operational optimization. Several international consultancies provide services that help building owners implement sustainability strategies and achieve LEED certification.
- ERKE Consultancy
- ARUP
- WSP Global
- Khatib & Alami
- Ramboll
- Linesight
- AtkinsRéalis
These consultancies offer varying capabilities ranging from sustainability advisory and engineering design to project management and operational modernization. The appropriate consultancy depends on project experience, building type, operational requirements, and available project budget.