What is the typical number of zones in a multizone system?

• A. More than 50 zones.
• B. 6 or fewer zones.
• C. Typically 12 or fewer zones.
• D. Exactly 20 zones.

Answer: (C)

The main idea here is how many zones a single multizone system can practically serve. In a multizone setup, one air handler provides supply air through dampers to multiple zones, with each zone having its own control to meet comfort needs. As the number of zones grows, the control complexity, balancing, and coordination challenges increase, along with potential energy use and ductwork complexity. To keep control straightforward and the system reliable and cost-effective, engineers typically design multizone systems with about a dozen zones or fewer. That’s why “typically 12 or fewer zones” is the best fit.

The other options describe extremes that aren’t representative of common practice: more than 50 zones is unusually large for a single AHU with zone dampers; 6 or fewer zones can be too small for many building layouts that still benefit from zoning; and exactly 20 zones is a precise number that isn’t a standard typical range.