Which could be an indication that a ventilation system is out of balance?

• A. All apartments have the same odor
• B. Only 1 apt complains about odors among a series of apts in a row
• C. There is increased humidity in the lobby
• D. Smoke detectors are all active

Answer: (B)

Air moves evenly through a balanced ventilation system, so problems tend to show up as localized issues rather than everywhere at once. If only one apartment in a row reports odors, it points to uneven airflow along that branch—some units aren’t being ventilated or exhausted as intended, allowing stale air or smells to linger in that one unit. The rest of the building would typically feel normal airflow, which is why this pattern signals an imbalance.

If odors appeared in every apartment, that would suggest a building-wide source or a systemic issue with the ventilation, not a balance problem. Increased humidity in the lobby relates to moisture control in a common area, not the distribution balance to individual units. Smoke detectors being active is about safety alarms, not airflow balance.