Your BAS Is Not the Enemy — Schedule Drift Is

When HVAC runs after hours, occupants complain about comfort, or utility costs rise without an obvious explanation, the BAS is often the first thing blamed. But a BAS is rarely mysterious. In most cases, it is doing exactly what it has been configured to do.

A BAS does not know that a bell schedule changed last year, that a temporary override was meant to last one week, or that two teams updated the same equipment differently. It follows the logic, schedules, priorities, and overrides it has been given.

Across years of staffing changes, construction projects, holiday exceptions, controls upgrades, and emergency fixes, those instructions can accumulate. The result is schedule drift: a system whose behavior no longer reflects how the building is actually used.

At one school, a review of HVAC scheduling uncovered roughly 900 conflicts. That does not mean the controls system was inherently bad. It means the operating logic had become difficult for any person to see and manage as a whole.

Nobody writes 900 conflicts at once. They compound — a handful of exceptions per season, each reasonable on its own, none ever retired:

The practical response is not less software. It is to make the BAS easier to understand and govern. Facilities teams should periodically review schedules, overrides, calendars, and equipment logic. For complex portfolios, an experienced controls consultant can provide a valuable outside review.

Edviro can help review BAS schedules and operating signals alongside meter data, bills, alarms, and work orders. The goal is to make sure the software faithfully carries out the facilities team’s intent.