Investigating Thermal Comfort in Vernacular and Contemporary Houses in Al-Qassim's Hot-Arid Climate

Abstract

Contemporary residential buildings in the hot-arid climate of Saudi Arabia with no or minimum insulation heavily rely on mechanical cooling, resulting in high electricity consumption. In the context of climate emergency, energy consumption based on fossil fuels is a high contributing factor. This research aims to investigate residents’ behavioural and cultural aspects of thermal comfort perceptions and adaptation and their relationship to objective measurements of air temperatures in vernacular and contemporary single-family houses in Al-Qassim, Saudi Arabia. The research does this by recording and evaluating the temperature measurements outside and inside eight vernacular and ten contemporary case study houses and thermal comfort perceptions of residents in the summer hot season of 2020 during a period of two consecutive weeks. Contemporary houses were selected from four neighbourhoods in Buraydah, while vernacular houses were chosen based on their accessibility, current condition and the availability of previous occupants for interviews. Open-ended structured interviews were conducted with eight elderly individuals to record their oral memories about living in the case study vernacular houses, while one resident from each of the 10 selected contemporary houses was interviewed in depth about their behaviour in their living room regarding maintaining comfortable temperatures. In addition, male and female occupants of contemporary houses were asked to rate their thermal comfort levels in their air conditioned living room twice a day. A typical house was chosen for a simulation model based on electricity bills and construction details. Three insulation scenarios in walls, roofs, or both were tested according to the Saudi Building Code. A comparative simulation was conducted to compare the unoccupied temperatures of vernacular houses with simulated conditions in contemporary ones, both under free-running and air-conditioned conditions. The research reveals that vernacular houses maintain warmer temperatures at night compared to outdoors, while contemporary houses are warmer during the daytime. Residents employ adaptive strategies in vernacular houses, such as sleeping on roofs. In contrast, residents in contemporary houses keep windows shut and rely on air-conditioning despite cooler nighttime temperatures. In the comparative simulation, vernacular house with and without air-conditioning, performed better than contemporary ones due to its lower U-value. The results of this study provide a new understanding of behavioural and cultural aspects from the past and the present related to maintaining thermal comfort, leading to a set of recommendations. The findings have broader applicability to similar climates and cultural contexts, including other Gulf Cooperation Council countries.