The building envelope is a critical component of any facility since it protects thebuilding occupants and plays a major role in regulating the indoor environment. Consisting of the building’s foundation, walls, roof, windows, and doors, the envelope controls th e flow of energy between the interior and exterior of the building. A well designed envelope allows the building to provide com fort for the occupants and respond efficiently to heating, cooling, ventilating, and natural lighting needs. Today we will exami ne the elements of the buildingenvelope (floors, walls, windows and ceiling) and how those elements participate in heat transfer. We will discuss heat loss or gain due to transmission, infiltration and ventilation. This course contains many equations used to deter mine heat loss and gain through the building envelope, and we will supply a sample case study of a building throughout the c ourse to help explain each topic.