Evaluation of occupants’ satisfaction in green and non-green office buildings in Dar es Salaam-Tanzania

Abstract

In recent years, sustainability practices in Africa have been promoted as the relatively most effective means of reducing adverse environmental impacts associated with buildings and occupants. Occupants' perception within buildings, whether green or non-green, is crucial for the understanding of building sustainability (energy performance) and comfort conditions. However, there has been a scanty research-based knowledge from empirical studies, particularly in Dar es Salaam. This study endeavoured to bridge that knowledge gap. The study evaluated the occupants' satisfaction rate of 2 certified green office buildings and 15 non-green office buildings and the extent to which they control indoor environmental performance. The study deployed a PoE questionnaire based on two types of scales, a bipolar and unipolar scale to measure the occupants' perception of the indoor environmental performance: temperature comfort, temperature sensation, noise, air movement, air freshness, air quality and satisfaction with the amount of natural light. A total of 532 occupants from the buildings set provided valid responses. The results show that overall occupants were quite satisfied in all buildings set. However, there are some differences regarding air movement, air quality, glare from artificial light, noise levels, and lighting control. Occupants of green buildings were more satisfied with lighting control; nonetheless, improved lighting control alone is insufficient to enhance occupants’ satisfaction in green buildings to a superior level than that of non-green buildings. This study can provide feedback to building owners, property managers, green building certification systems and can aid architects in designing climate-responsive buildings that encourage long-term occupant satisfaction.