Differences in climate are caused by the differential solar heat input and the almost uniform heat emission over the Earth’s surface. The most important climate variables in building design are those that directly affect thermal comfort: temperature, humidity, solar radiation, and air movement. The amount of energy used in a building is a direct result of the interactions among the external environment, the building’s program, and the building’s form. An interesting example of non-vernacular architecture adapted to a warm and humid climate is the architecture for oil and fruit companies of the early to mid-twentieth century. A building in a warm and dry climate is usually a compact heavy mass structure that modulates outdoor temperatures, with small windows to reduce solar gains to the interior of the space but that allow some ventilation for night cooling. Operational emissions involve all the emissions produced from the energy used to keep the buildings and everything inside it running.