Buildings are responsible for a significant portion of global energy use and carbon emissions, making green retrofits a critical strategy for achieving sustainability targets. While new buildings can be designed for high performance, existing buildings require periodic retrofitting to maintain efficiency, safety, and occupant comfort. This study proposes a structured method based on the Analytic Network Process (ANP) to holistically evaluate the performance of retrofit projects in commercial buildings. The model integrates multiple key performance indicators (KPIs) across environmental, economic, health and safety, and user-oriented aspects. A real-world case study in Hong Kong demonstrates how the method sup-ports decision-making and post-retrofit evaluation, offering facility managers a practical and adaptable tool to align project outcomes with sustainability, compliance, and operational goals. The case yielded a Building Retrofit Performance Index (BRPI) score of 4.37 out of 5, confirming the model’s practical utility.

Among many retrofit options, lighting retrofit is one of the popular choices. This paper reports application of key performance indicators (KPIs) on assessing lighting retrofit performance in commercial buildings in Hong Kong. The im-portance level of KPIs including energy saving (%), payback period (year), in-vestment cost ($) and target work plane illuminance (lux) were investigated. The projects involved lighting retrofits such as the replacement of energy-efficient lamps (e.g. LED). The scale of the lighting retrofit projects ranged from HK$0.1M to HK$3M, and the project periods were between 2 months and 3 years. Results showed that the average relative importance level (w) of target lighting illuminance level was 8%. It was also vital to consider the environmental and economic factors such as energy saving (w: 32%), payback period (w: 36%) and investment cost (w: 24%). The performance rating for target lighting illuminance was highest (average: 5 out of 5), followed by energy saving and investment cost (average: 4 out of 5), while payback period was rated the lowest (aver-age: 3 out of 5). To further enhance energy efficiency in retrofit projects, more case studies can be conducted with the application of Artificial Intelligence technologies and examine its actual impact on energy saving.

The rapid urbanisation and climate change challenges faced by tropical, dense megacities, such as Dhaka, demand a deeper integration of climatic considerations into building design, especially for enhancing daylighting and energy efficiency in educational spaces. Ensuring occupant comfort and well-being in public and educational buildings is important for fostering a productive learning environment. As part of the path toward net-zero energy buildings, passive design strategies, such as optimising building form and envelope, alongside integrating renewable energy systems, are increasingly recommended as sustainable solutions. This study focuses on the alternative design performance of a five-storey educational building in Dhaka as the case building. Using simulation tools, e.g., ClimateStudio and Grasshopper, the study evaluates key performance metrics, including average illuminance, spatial daylight autonomy (sDA300/50%), annual sunlight exposure (ASE1000,250h), Leadership in Energy and Environmental Design (LEED) points, daylight glare probability (DGP) and energy use intensity (EUI). The research highlights the effectiveness of a hybrid approach combining envelope systems and solar panels for achieving net-zero energy performance, particularly in tropical climates. The building was evaluated across three design phases: the existing building with integrated louvres, an alternative building form accommodating additional functions considering the existing structural system, and the addition of a new design featuring ethylene tetrafluoroethylene (ETFE) panels with integrated photovoltaic (PV) modules. Simulation results demonstrate the effectiveness of iterative envelope design strategies in improving both daylight performance and energy efficiency. The design evolved from a base case with limited daylight (410 lux, 46% sDA300/50%) to an optimised ETFE with PV façade achieving better daylight availability (921 lux, 76.3% sDA300/50%, DGP 11.3%) compared to the base case (410 lux, 46% sDA300/50%, DGP 44.6%) and net-positive energy performance (gradually reduced energy use from 561,367 kWh/yr to a surplus of 6,739 kWh/yr). The findings highlight the potential of climate-adaptive building envelopes to address daylighting challenges in local contexts. This research emphasises simulation-based design and advanced façade systems for sustainable educational buildings in rapidly urbanising, high-temperature regions.

Energy efficiency has been a key driver in shaping building construction codes over the past two decades. However, a notable unintended consequence of these advancements has been reduced ventilation, leading to elevated indoor moisture levels. Moisture condensation in unvented attics is a serious problem in marine climates because it can remain hidden causing significant damage prior to detection. Many attic condensation problems occur in homes despite having been built to code. A better understanding of moisture vapor transport into unvented attics is needed to understand and effectively address this problem.

Attics by their very proximity to the roof can undergo large temperature changes, and as attic temperatures plummet at night, the air contracts and draws indoor air into the unvented space via gaps. This transport mechanism of moisture into the unvented attic is investigated.

Detailed temperature and relative humidity data is collected at multiple locations within some homes with unvented attics to build hygrothermal models. Some homes chosen for the study have preexisting hygrothermal concerns. Data collected includes the timing and extent of household activities that add moisture to the indoor air.

Low ventilation and moisture release from indoor activity raise the indoor humidity. The model predicts transport of indoor air, i.e. leakage, into the attic. The moist indoor air undergoes condensation in the attic. Experimental data is used to validate the model and predict the quantity of condensation taking place in the unvented attic.

This study explores indoor air leakage into unvented attics and its condensation in concealed spaces. Recommendations are made for improving the design of attics to make a better trade-off between thermal efficiency of homes and moisture management in unvented spaces.

This study comparatively evaluates the effects of eleven alternative fur-niture layouts developed parametrically with the current layout on the natural lighting performance of Istanbul Ticaret University Küçükyalı Campus Library. Within the scope of the study, spatial models created with AutoCAD and SketchUp software were integrated into the Rhino–Grasshopper platform; daylight analyses were performed using the Hon-eybee plugin. In accordance with international standards, sDA (Spatial Daylight Autonomy), ASE (Annual Sunlight Exposure) and UDI (Useful Daylight Illuminance) metrics were adopted as basic performance crite-ria. According to the analysis results, in the current layout, positioning the stacks directly in front of glass surfaces limits the homogeneous dis-tribution of daylight throughout the interior with a performance of sDA 60.21%, UDI 74.57% and ASE 5.63%. In alternative layout scenarios, significant increases in sDA and UDI values were observed in arrange-ments where the shelves were moved away from the facades and the work areas were brought closer to natural light sources. The highest sDA value was obtained in scenario number 7 with 75.20%, while the lowest ASE value was obtained in the current layout with 5.35%. The results show that furniture placement is a decisive design input not only in terms of functional circulation and aesthetic continuity, but also in terms of daylight performance and optimization of user-oriented visual comfort.