Why is balancing and airflow verification important in commissioning?

• A. Only affects energy use, not comfort.
• B. Unrelated to commissioning.
• C. Only for new buildings.
• D. Ensures rooms receive proper ventilation and comfort; affects energy use and IAQ.

Answer: (C)

Balancing and airflow verification ensure the HVAC system delivers the right amount of air to each space and maintains the intended pressure relationships between areas. In commissioning, this means measuring actual airflow at diffusers and returns, adjusting dampers and fans so each zone gets its target ventilation, and verifying that the system meets the design intent and applicable standards for ventilation rates.

When airflow is correctly balanced, rooms receive proper ventilation for comfort and indoor air quality. This reduces problems like stuffy rooms, high CO2, humidity, odors, and uneven temperatures, which directly impact occupant comfort and health. At the same time, proper balancing supports energy efficiency: equipment runs at the levels needed for actual occupancy and use, avoiding wasted fan power from over-ventilation or constant fighting between zones.

Balancing isn’t limited to new buildings. Over time, systems can drift due to filter restrictions, duct leaks, damper wear, or changes in occupancy and usage. Verifying and rebalancing as part of commissioning or re-commissioning helps restore design intent and sustains performance.

So the best understanding is that balancing and airflow verification ensures rooms receive proper ventilation and comfort, and it influences energy use and indoor air quality. The idea that this practice is restricted to new buildings isn’t correct because its benefits apply to both new projects and existing facilities undergoing commissioning or re-commissioning.