Charles joined IEN Consultant since 2012 after graduated from a joint master program by University of Applied Sciences Rosenheim and University Kuala Lumpur which focus in green and energy efficiency design in building. His master thesis was about further optimizing a building's performance by analyzing data collected from the building automation system, which remain as his passion and main interest until today. He had completed building data analysis and optimization for numerous projects such as ST Diamond building, KLIA 2, and Menara Shell.

Apart from data analysis and optimization, energy efficiency design for ACMV and electrical services are also part of his core competency. By utilizing simulation software such as IES Virtual Environment, he is able to propose to the client and project team a more energy efficient system and often avoid unnecessary spending in hugely oversized systems.

Other than energy efficiency design, he is also specialised in water efficiency design, good indoor environmental quality design, and low carbon building design which are part and parcel of the overall green building design and certification. Malaysia Green Building Index (GBI) certification and United State Leadership in Environmental and Energy Design (LEED) certification are his most familiar green building certifications.

Apart from design, he is also experienced in actual equipment installation and site measurement and commissioning. He had completed a mini demonstration project for University Kuala Lumpur which involved design, installation and commissioning of an 10 kW adsorption chiller from Invensor, Germany. He is often involved in ACMV system performance measurement, daylight and lighting level measurement and other indoor comfort measurments.