Weather compensation in BAS is used to

• A. Adjust HVAC setpoints based on outdoor weather data to improve efficiency.
• B. Adjust lighting schedules based on outdoor light levels.
• C. Monitor occupancy in spaces.
• D. Forecast future energy prices.

Answer: (A)

Weather compensation is a control approach that uses outdoor weather data to adjust how the HVAC system operates, rather than relying on fixed indoor setpoints. By applying the outdoor temperature (and sometimes other conditions) through a calculated curve, the BAS determines the appropriate supply or target temperatures for heating or cooling. On milder days, the system lowers the heating output to save energy; on colder days, it raises it enough to maintain comfort. This keeps indoor conditions steady while reducing energy use, especially with efficient boilers, by preventing unnecessary heating and reducing sensor overshoot or short-cycling. The other options describe daylight harvesting, occupancy monitoring, or price forecasting, which are different functions and not what weather compensation does.