The effect of vegetation on indoor and outdoor thermal comfort conditions: Evidence from a microscale study of two similar urban buildings in Akure, Nigeria

Abstract

This study assessed thermal conditions in and around two typical buildings on a university campus in Akure, Nigeria. One of the buildings was shaded by trees, while the other was unshaded. The aim is to evaluate the effect of vegetation (tree shading) on indoor and outdoor thermal comfort. Air temperature and relative humidity were measured simultaneously inside and outside both buildings for six months (September 2010 to February 2011). Results show that the unshaded building is generally less comfortable in comparison with the tree-shaded one, especially during the daytime. The unshaded building becomes less comfortable as early as 10:00 h during the dry season, and that can even extend till around 18:00 h during the wet season. Also, the outdoor area around the tree-shaded building is more thermally comfortable than around the unshaded one, irrespective of the season. A strong relationship between outdoor and indoor comfort conditions, irrespective of seasonal or diurnal variations and thermal comfort index, also emerged. While the positive role of tree shading in thermal comfort is not new, this study contributes additional evidence from an understudied sub-Saharan African region like Nigeria. It points to the need for tree planting (greening) as a means to improve thermal comfort in Nigerian cities.