Which term describes data needed by all HVAC controllers in a network, including outside air temperature and electrical demand?

• A. Local data.
• B. Global data.
• C. Historical data.
• D. Sensor data.

Answer: (B)

Global data represents values that all HVAC controllers across a network need to know to coordinate actions. Outside air temperature is a condition that affects the entire building, influencing ventilation strategies, economizer operation, and overall energy use, so every controller must have access to it to make consistent decisions. Electrical demand is a system-wide constraint used for peak shaving and staying within demand limits; sharing this data ensures the controllers can collectively manage the building’s load. In contrast, local data is specific to a single controller or zone, historical data refers to past measurements for analysis, and sensor data is raw readings from individual sensors. The data shared by all controllers—data like outside air temperature and electrical demand—fits the idea of global data.