A tenant complains, someone overrides a damper and never puts it back. A floor empties but its schedule stays. A sensor ages and reads a few degrees off. Each change is small. Together they quietly add a large share to the energy bill. Here are the patterns we look for first.
Rules fighting each other
Heating and cooling running at the same time, in one air handler or between perimeter heaters and central cooling. Usually caused by overlapping setpoints or a deadband set too narrow. It's one of the most expensive faults, and invisible on a normal screen.
Plant running when nobody's there
Energy use at 3 a.m. or on Sundays close to weekday levels. Schedules never updated after a change in hours, holiday calendars missing, or a permanent override left on.
Overrides nobody remembers
Points left in manual or hand mode. Each one began as a quick fix for a complaint. Many stay for years after the reason is forgotten.
Sensors that read wrong
A reading that never moves, or one that disagrees with a handheld meter. A sensor a few degrees out can keep a space heating or cooling all day. Why a second reading matters.
Complaints in the same places
Repeated "too hot" or "too cold" calls from the same rooms usually point to a control problem, not to the people in them.
Why it's worth fixing
A Lawrence Berkeley National Laboratory analysis of 643 buildings found that commissioning existing buildings, finding and fixing faults like these, delivered median energy savings of 16%, with a median payback of 1.1 years. Most of those fixes were settings and programming, not new equipment.
Three things you can check this week
- Export a week of trend data and look at nights and weekends.
- Ask your BMS contractor for a list of every point in manual override.
- Check a few room sensors against a handheld thermometer.
Rather we looked?
A Pasot assessment finds these faults, puts a cost on each, and tells you what it takes to fix them.