Mechanical space-conditioning systems supplying heated or cooled air to multiple zones shall include controls that automatically reset supply-air temperatures:
- In response to representative building loads or to outdoor air temperature; and
- By at least 25 percent of the difference between the design supply-air temperature and the design room air temperature.
Air distribution systems serving zones that are likely to have constant loads, such as interior zones, shall be designed for the air flows resulting from the fully reset supply-air temperature.
- Systems that meet the requirements of Section 144(d) of Title 24, Part 6, without using Exception 1 or 2 to that section.
- Where supply-air temperature reset would increase overall building energy use.
- Zones in which specific humidity levels are required to satisfy process needs.