The building is well-known for its excessive energy usage, associated with greenhouse gas emissions (pollution). The primary contributors to this excessive energy use are the heating and air conditioning systems used to maintain indoor thermal comfort. Due to the difference between the indoor and outdoor environments, a continuous heat exchange occurs between the building and its external environment. The current study aims to determine the thermal exchanges between a room and its surroundings through its walls during both daylight hours (when solar radiation is present) and nighttime (in the absence of sunlight). To achieve this objective, a brick room measuring 20 cm x 20 cm x 20 cm was constructed with four walls oriented towards the four main directions: east, west, north, and south. Temperature measurements were taken every minute at the midpoint of each wall's outer surface, as well as at the center of the room. These measurements were conducted using a specialized acquisition system during the spring months of April, May, and June in Ouled Sidi Brahim, which is located in northern Algeria. In the morning, the walls oriented towards the north and east exhibit higher temperatures than the room's inside, thereby contributing to its heating. In contrast, the walls facing west and south are cooler than the internal space, which results in a cooling effect as they permit heat to dissipate into the external environment through these two orientations. Conversely, in the afternoon, the sun is positioned in the south-western part of the sky. Consequently, the walls oriented towards the west and south facilitate an increase in room temperature, whereas those facing east and north assist in lowering it. At night, the heat accumulated in the room during the day escapes through its four walls to the surrounding environment, which tends to cool down in the absence of the sun. The indoor temperature is significantly affected by the temperature of the walls' outer surfaces. In other words, the orientation of the walls affects indoor thermal comfort. Models with a high correlation coefficient (R² > 0.95) were proposed for each month using stepwise linear regression, in which the indoor temperature was related to the outer surface temperatures of the walls. The contribution of the wall's orientation varies as the sun moves during the spring months. The orientation of walls significantly influences thermal exchanges, specifically regarding heat gains and losses. This research facilitates the optimal placement of rooms within a residence based on their intended use, thereby promoting energy cost savings.