Building facades play an important role in thermal loads, which act as an isolation barrier to ensure thermal comfort to the occupants. Depending on the properties of the building material adopted, each component of a building facade may lose or gain heat, contributing to the building’s thermal load.
There is a growing need to examine the role that external construction components play from an energy perspective towards achieving environmental comfort in buildings.
The novelty of this research is to propose a methodological framework based on Design of Experiments (DOE) that characterizes the thermal loads that are directly caused by variables controlled by building designers and consultants. Such variables include external construction components (walls and openings assessed via window-to-wall ratio), air infiltration rate, artificial lighting, occupation levels, heating, and cooling equipment, and appliances during the operation phase of a building, taking into consideration the local climate data in which the building is located.
This work validates the proposed method with a case study of a single-family house, which provides a better understanding of the influence and interactions of design factors on building thermal loads.
Results reveal that the window-to-wall ratio has a major influence on evaluating the thermal loads in buildings. The higher the ratio, the higher the value of the thermal loads.
The proposed framework aids designers in determining the components that are influencing thermal loads in buildings, as well as the required window-to-wall ratio.
Findings highlight that construction components of external walls and openings are responsible for around 93.9–97.58% of thermal loads in buildings.
Furthermore, this work presents the important role of sustainable building decisions at an early stage of designing construction projects.