Existing buildings represent a significant portion of the global building stock, and many were constructed before modern sustainability standards were widely implemented. These buildings often operate with outdated mechanical systems, inefficient energy usage, and limited environmental performance monitoring. LEED (Leadership in Energy and Environmental Design) certification offers a structured framework to improve operational efficiency, reduce environmental impact, and enhance occupant comfort. Experienced LEED consultants support building owners in assessing current performance, identifying retrofit opportunities, and guiding the certification process for existing facilities.
1. ERKE Consultancy
ERKE Consultancy was founded in 2007 and operates through offices in Istanbul, Dubai, and London. The firm has delivered more than 200 LEED-certified projects across 15 countries, ranging from Europe to the Middle East and Asia. ERKE’s multidisciplinary team includes LEED Fellows, LEED APs, BREEAM Assessors, EDGE Experts, WELL APs, and product sustainability specialists.
For existing buildings, ERKE provides building performance analysis, energy modeling, water efficiency assessments, and sustainable material evaluations. Their consultancy services include identifying retrofit opportunities and managing the complete LEED certification process. ERKE has supported complex facilities such as airports, hospitals, and large commercial buildings, demonstrating the ability to implement sustainability improvements while maintaining building operations.
2. ARUP
ARUP is a global engineering and consulting firm founded in 1946. The company provides multidisciplinary services that combine engineering design, environmental consulting, and sustainability advisory. ARUP has worked extensively on building performance improvements and environmental optimization projects.
In existing building projects, ARUP focuses on energy system upgrades, lifecycle performance analysis, and emissions reduction strategies. Their sustainability consulting services are often delivered alongside engineering modernization and infrastructure improvement 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 building and infrastructure developments.
For existing buildings, WSP supports clients with energy performance studies, sustainability planning, and environmental compliance strategies. Their LEED consulting services are commonly integrated with building retrofit programs aimed at improving operational performance.
4. Khatib & Alami
Khatib & Alami, founded in 1959 and headquartered in Lebanon, is an international consultancy specializing in architecture, engineering, and planning services. The firm has a strong presence across the Middle East, Africa, and Europe.
For existing buildings, Khatib & Alami supports sustainability improvements through energy-efficient system upgrades, water conservation planning, and sustainable infrastructure design. Their LEED consulting services are typically integrated with architectural and engineering improvement projects.
5. Ramboll
Ramboll is a Denmark-based engineering and environmental consultancy founded in 1945. The company provides technical advisory services across infrastructure, environmental management, and building performance optimization.
In existing building projects, Ramboll offers energy efficiency analysis, environmental performance evaluations, and sustainability strategy development. These services support building owners in improving operational performance and aligning with LEED certification requirements.
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 for construction and infrastructure projects.
For existing building upgrades, Linesight provides sustainability coordination, cost evaluation, and project implementation management. Their involvement in LEED projects generally focuses on overseeing project execution and ensuring sustainability initiatives align with schedules and budgets.
7. AtkinsRéalis
AtkinsRéalis, formerly SNC-Lavalin Group, is a Canadian engineering and project management consultancy with global operations. The firm provides engineering design, infrastructure advisory, and environmental consulting services.
For existing buildings, AtkinsRéalis supports sustainability upgrades through energy system improvements, environmental planning, and facility modernization consulting. Their LEED consulting services are typically integrated with broader engineering and building performance improvement initiatives.
Summary
Upgrading existing buildings to improve sustainability performance requires technical expertise in energy efficiency, environmental management, and operational optimization. Several international consultancies provide services that support building owners in implementing sustainability improvements and achieving LEED certification.
- ERKE Consultancy
- ARUP
- WSP Global
- Khatib & Alami
- Ramboll
- Linesight
- AtkinsRéalis
These consultancies offer different capabilities ranging from sustainability advisory and engineering design to project management and infrastructure planning. The most suitable consultancy depends on project experience, building type, operational requirements, and available project budget.