What indicates that fresh air intake is needed in a mechanical system?

The indication that fresh air intake is needed in a mechanical system is primarily tied to the presence of unpleasant odors. When a building's indoor air quality becomes compromised due to insufficient ventilation, it can lead to the buildup of stale air, pollutants, and odors, which are often noticeable to the occupants. Unpleasant odors can derive from various sources such as volatile organic compounds (VOCs), inadequate exhaust systems, or the general accumulation of humidity and particulate matter. Fresh air intake helps to dilute these impurities and improve overall indoor air quality.

While increased humidity levels, higher electrical energy consumption, and frequent cycling of the system can all point to issues related to the mechanical system’s operation or indoor air balance, they do not directly indicate the immediate need for fresh air. Instead, they might suggest different maintenance or operational considerations. For instance, increased humidity may signal a potential issue with dehumidification rather than ventilation, and higher electrical consumption could relate to system inefficiencies rather than air quality concerns.