To better understand the current status quo of LCA with respect to lighting technology, including electric lighting as well as daylighting and façade issues

• a survey among 15 participating countries of IEA SHC Task 70 / EBC Annex 90 “Low Carbon, high comfort integrated lighting” and
• a review of scientific literature based on 59 relevant research articles

have been conducted.

The conducted survey investigated the general level and kind of decarbonization efforts and LCA use in the overall building section, of which lighting and façade/daylighting aspects are part of. The main identified open issues in integrating Life Cycle Assessment (LCA) better into building practice are the need for more accessible LCA tools and databases, increased transparency in LCA methodologies, lack of LCA focus in training architects and engineers, and the complexity of LCA. There's a need for simpler tools to quantify environmental performance of projects. A need for carbon emission limits in building regulations is expressed, similar to energy consumption limits.

The scientific literature shows that future trends in Life Cycle Assessment (LCA) for luminaires emphasize a more integrative approach across product development stages, incorporating circular economy principles and modular design. Designing for disassembly and reassembly enhances maintenance efficiency and reduces environmental impact. Modular LED luminaires can lower carbon footprints by approximately 30 % through component replacement instead of full unit disposal. Despite these benefits, challenges remain, including labour costs, certification gaps, and limited data transparency from manufacturers. Standardized data collection and closer collaboration between manufacturers and environmental analysts are essential for improving LCA accuracy and sustainable lighting design. Façade / daylighting systems have been found to be less studied in literature, with most of the focus on windows, frames and glazing, while shading systems remain underexplored. Simulation-based studies dominate over real-case studies and applications. Regardless of lighting scenarios, the use phase has the highest environmental impact, emphasizing the need for efficient planning, energy-conscious operation, and proactive maintenance to sustain performance.

In the new buildings, almost only LED systems are now being designed. The majority of existing plants, on the other hand, have not yet been converted to LED technology and hold great and often easy-to-develop climate protection potential: so-called “Low Hanging Fruits”. In the conversion forced by the phasing out of fluorescent lamps (e.g., in the EU this year, 2023), the main question is whether “transitional solutions” in the form of LED replacement lamps make sense or whether it would be better to switch to more powerful LED lights right away. However, the focus of renovations is not solely on the high efficiency of the LEDs. New control options should also be considered wherever possible in coordination with the most sustainable light source, daylight. In addition, the understanding of user needs has evolved in recent years [1], so that, with proper planning, renovations also ensure an improved and performance-enhancing quality of stay with increased visual comfort in rooms.