Thermal performance assessment of an 18th-century historic building in Ceará

Thermal performance refers to a building’s efficiency to maintain indoor comfort conditions in response to climate variations. It represents a key factor in the quality of the built environment. Regarding heritage buildings, their thermal performance is associated with constructive features that employ passive design strategies to reduce environmental impacts. However, current climate change intensifies thermal variations and extreme events, compromising occupant comfort, thermal performance, and physical integrity of historic buildings. This study analyzes the thermal performance of an 18th-century historic building in Ceará, aiming to understand its behavior under the local climate and identify potential improvements. The research combined technical inspection, observation of passive design strategies, mortar sampling, and computational simulation in Revit, along with physical, chemical, and morphological characterization of the material. The results indicate that the historic building exhibits stable thermal behavior, mainly due to the high thermal inertia of its original building materials. Energy simulation estimated an annual cooling consumption of 485.04 kWh, a value significantly lower than those normally reported for contemporary buildings in similar climatic conditions. Indoor air temperature and relative humidity remained within the comfort range recommended by ANSI/ASHRAE 55 (2020). Thermal comfort assessment resulted in a PMV of 0.43 and a PPD of 9%, indicating slightly warm but acceptable conditions for most occupants. These findings suggest that the passive strategies incorporated into the historic structure contribute to reducing cooling demand and promoting acceptable indoor thermal conditions.