If you wanted to think of a market segment that contains nearly every complication possible for a mechanical service provider to contend with, it would probably be the school market, particularly K-12. Operating budgets are tight; heat loads vary considerably throughout the day, and sometimes small parts of the building are used after hours.
IAQ is a major concern because younger students, in particular, have less developed immune systems and they spread a lot of germs; staff has a different perception of comfort from room to room; doors are opened and closed throughout the day - every hour students pour through the hallways, creating strong airflow patterns. The maintenance staff may or may not fully understand the needs of the HVAC system, and chances are the staff is stretched thin; is maintenance being performed often enough, or at all?