A reset schedule automatically adjusts HVAC setpoints based on outdoor conditions, occupancy, or time-of-day to optimize equipment efficiency and comfort. Reset strategies reduce energy consumption 10-25% by maintaining less stringent conditions when they are acceptable and staging equipment startup before occupancy. Common reset methods include outdoor air reset, occupancy-based reset, and demand-controlled reset.
Reset Strategy Types
Outdoor air reset adjusts chilled water supply temperature from 45°F at 95°F outdoor to 55°F at 65°F outdoor, reducing cooling load staging. Hot water reset raises setpoint from 140°F at 60°F outdoor to 160°F at -10°F outdoor. Time-of-day reset reduces cooling setpoint to 76°F unoccupied, switches to 72°F occupied, and pre-stages equipment 30 minutes before occupancy.
Implementation and Benefits
Reset schedules integrate with building automation systems using linear equations or step functions programmed into DDC controllers. Applications include office buildings, schools, and retail facilities with predictable occupancy patterns. Demand reset based on zone sensors further optimizes system staging: enable heating only when 2 of 8 zones request heat, reducing short-cycling and extending equipment life.