What does 'smart buildings' actually mean?

Breaking down the concept of smart buildings into real terms

A smart building is one that contains IoT sensors that can measure various important factors that can drive decisions from the data they display. For example, occupancy sensors can measure building, meeting room and desk occupancy over a given period of time and provide reports that office managers can use to drive decisions around the most economic use of space. Additionally, sensors that detect usage of heat and energy sources can drive decision making around how best to manage use of these devices and drive down energy bills and carbon footprint.