Challenges of Providing Natural Ventilation and Daylighting in Small Plot Urban Dwellings: The Case of Adama’s 105m2 Plot

Abstract

Although it has been challenging to ensure adequate natural ventilation and daylighting in such high-density urban settings, small-plot residential development is steadily spreading across Adama City. This study evaluates the indoor environmental quality of eight small-plot dwellings (≤105m²) with various site layouts and orientations. It focuses on airspeed, relative humidity, daylight illuminance, and indoor air temperature. Multiple daily measurements of the indoor environmental factors in each home's living room, bedroom, kitchen, and toilet were made during the hottest months of April 29–May 1. The outcomes were then contrasted with the IES daylighting recommendations and ASHRAE 55 thermal comfort criteria. While the master bedrooms in all tests recorded 0 lux at around 0 lux daylight and very low air speed, indicating acute lack of sunshine and ventilation, quantitative data show that most rooms, particularly bedrooms and bathrooms, lack the recommended thermal comfort requirements and daylight. While sunshine levels in large locations stay below 140 lux, below the standards for comfort, indoor temperatures in east-west aligned and closed homes can rise above 30°C during the hottest hours. Air speed readings are consistently less than 0.2 m/s, typically 0.01 m/s, which limits the efficiency of natural ventilation. Even if T-junction layouts help a little, the issue still exists, particularly in deep interior locations like bathrooms and master bedrooms. According to qualitative data collected from the existing buildings through interviews with the architects, urban planners, and occupants, the main obstacles are narrow plot widths, shared walls, and few formal regulations. The occupants report frequent overheating, poor indoor quality, and a lack of daylight, frequently turning to artificial lighting and mechanical fans for ventilation or not using any ventilation at all. It is determined that Adama City's current small-plot development methods fall short in addressing the vital problems of daylighting and natural ventilation. Poor indoor environmental quality is the outcome of these flaws, particularly in densely populated urban areas. Adopting an integrated strategy that combines design innovation and policy reform is crucial to enhancing comfort and sustainability. Important steps include promoting layouts that improve natural airflow and daylight penetration, giving passive design techniques like stack ventilation and skylights priority, and updating urban legislation to better promote ideal plot arrangements. In the quickly urbanizing context of Adama, such coordinated design and policy initiatives are required to successfully increase indoor environmental quality.