Single-Point Zoning is a simplified approach to point airflow control. It does not seek to run the equipment or control delivery to the entire space. Rather it is a single thermostat talking to one or more dampers to improve conditions in one space.
Building Science has come a long way. Most buildings mostly work. That being said almost every building has a couple areas that are either over or under-serviced. This is where Single-Point Zoning comes in.
Over service – this is the easy one to think about. If a space periodically is over served, either because of variable loads, changes in occupancy or other usage factors, a modulating damper will open only when there is a demand matched by the available service.
Under-Service – A little tricky: late afternoon west glass loads, high-density areas, areas without thermostats of their own, often don’t get the service they need to stay comfortable. The answer is to close off a few runs somewhere else (lower priority space), increase static pressure so more conditioned air is pushed into the space.