Adoption and Effectiveness of Energy-Saving Lighting Technologies in Office Buildings: Evidence from Dar es Salaam, Tanzania

Abstract

This study was conducted to assess how energy-saving lighting technologies are being adopted and to evaluate their effectiveness in real-world settings. A cross-sectional quantitative survey involving on-site audits was conducted across 25 multi-storey office buildings selected through stratified sampling. Descriptive statistics, spatial heatmaps, and regression analysis were used to examine the prevalence, spatial deployment, and performance of lighting technologies. Descriptive analysis indicates a strong positive association between motion sensor deployment density and energy efficiency outcomes (r = 0.93); however, this relationship is scale-mediated since larger buildings naturally have more sensors and higher absolute energy use and should not be interpreted as a direct causal effect. Building size was considered as a contextual factor throughout the analysis. Motion sensors are installed in only 40% of buildings and mainly in low-use areas like lobbies and restrooms. Further analysis revealed that energy savings are significantly influenced by the extent of coverage rather than mere adoption. These findings are important for informing urban energy strategies. The study recommends prioritizing sensor installation in high-occupancy zones, incentivizing retrofits, and ensuring regular maintenance. Overall, it offers a practical framework to enhance lighting energy efficiency in rapidly urbanizing cities like Dar es Salaam.

Keywords: lighting energy efficiency; motion sensors; energy-saving technology; office buildings; Dar es Salaam