Optimization of energy consumption in lighting through window-to-wall ratio (WWR) in prefabricated social housing under warm climate conditions

The influence of window-to-wall ratio (WWR) on energy consumption for lighting and visual comfort in a social housing building in Bucaramanga, Colombia, was investigated. Using parametric simulations in Design Builder, WWR between 0% and 100% were modeled in 10% increments, while structural and climatic conditions were kept constant. The results show that WWR values below 30% do not meet the minimum illuminance levels requires by Colombian regulations, while values above 70% lead to over-illumination and glare. The optimal range is between 40% and 60%, ensuring that regulations are met in most rooms. Monthly lighting energy consumption is reduced by up to 65% (approximately 650 kWh per year), and lighting uniformity is optimized. These results confirm that WWR regulation is an effective, reproducible, and cost-effective passive design strategy for increasing energy efficiency and living quality in social housing in warm climates.