In residential buildings, air infiltration impacts energy, indoor air quality, and thermal comfort considerably. While air infiltration in residential buildings has been the focus of many studies, most published field-testing results pertain to developed countries, with little or no data on air infiltration in developing nations. This paper presents the results of one of the first field investigations into envelope infiltration in the residential buildings of the hot-arid climatic area of Egypt. To analyze the air permeability of the building envelope, the fan pressurization method, often known as the blower door test (BDT), is used, following ISO 9772. The study focuses on 20 residential dwellings built with heavy construction materials and subjects them to extensive characterization and testing. The average air leakage and the air permeability rate for the tested sample were 6.14 h⁻¹ and 17.3 m³/(h∙m²), respectively. However, significant variations in airtightness were observed across the dwelling, leading the team to test several building-related parameters statistically to study their impact on airtightness. Fenestration quality appeared to be a critical factor in determining air infiltration, showing a strong correlation with the air change and leakage. A further investigation underscored that the specific aperture factor and the fenestration quality can predict the infiltration rates to a large degree. Thus, we recommend further investigation of these characteristics in heavy construction material building. Finally, we strongly recommend that building codes in developing countries such as Egypt include minimum performance requirements for fenestration.

Students and educators spend significant time in learning spaces on university campuses. Energy efficiency has become a concern among facility managers, given the need to maintain acceptable indoor air quality (IAQ) levels during and after the COVID-19 pandemic. This paper investigates the relationship between control and extraneous variables in a university classroom’s total mechanical ventilation (kWh). The model is built using Grasshopper software on Rhino Version 7. Our methodology encompasses (1) an extensive review of recent trends for studying IAQ and energy, (2) selecting parameters for simulation, (3) model configuration on Grasshopper, and finally, (4) a formulation of a pertinent equation to consolidate the relationship between the studied factors and the total mechanical ventilation energy (kWh). Central to this study are two key research questions: (1) What correlations exist between various parameters related to occupancy and IAQ in educational spaces? And (2) how can we optimize energy efficiency in university classrooms? The main contribution of this research is a generated equation representing the annual mechanical ventilation energy consumption based on selected parameters of classroom height, area, occupancy, window location, and ventilation rate of HVAC systems. We find that occupancy and class volume are the two most influential factors directly affecting mechanical ventilation energy consumption. The equation serves as a valuable estimation tool for facility managers, designers, and campus operations to investigate how fluctuations in occupancy can influence ventilation energy consumption in the physical attributes of a university classroom. This enables proactive decision-making, optimizing energy efficiency and resource allocation in real-time to promote sustainable and cost-effective campus operations.