Indoor environmental conditions in vernacular dwellings in Alentejo, Portugal

Abstract

Understanding the indoor environmental conditions of livable architectural heritage such as vernacular dwellings is a key step toward its conservation. Yet, there is a lack of large-sample studies that assess indoor conditions using long-term quantitative and qualitative data complying with monitoring standards. This paper addresses this gap in Portuguese vernacular dwellings using long-term mixed methods, by analyzing the thermal performance, indoor air quality, and illuminance of 22 case studies. Key findings highlight the role of thermal mass in damping the outdoor thermal wave and providing thermal stability, night ventilation, and lack of windows. Summer thermal performance bettered that of winter, but occupant control strategies negatively impacted thermal stability and overheating. In winter, the most prevalent heating system, electric, performed less efficiently than radiant heating, leaving occupants exposed to thermal discomfort and health risks from cold, mold, and toxins from wood-burning and cooking. Important discrepancies were found between the illuminance monitored and survey data, indicating the significance of cultural practices in indoor environment acceptability and expectations.