Occupancy Sensors Not Working? What We Usually Find.

Symptom → What We Usually Find

The typical story: an LED retrofit went in years ago, the install passed inspection, and the building has run on factory defaults since. Installation and commissioning are different trades, and the second one often never happened.

• Lights never turn off

  Timeout at the factory maximum, sensitivity too high for the space, zones mapped so a busy area holds an empty one on, or an override set during fit-out and never cleared.

• Lights won't turn on, or turn on late

  Sensitivity too low, or the sensor can't see the entry path. Occasionally a failed device; more often a coverage problem.

• Nothing ever dims

  Daylight harvesting disabled after early complaints instead of recalibrated, trim never set, or dimming drivers wired but never addressed into the control system.

• Whole zones behave identically, day and night

  Schedules never configured, so the system runs one default profile around the clock.

What Re-Commissioning Involves

Assess what's configured against what the spaces need, re-tune or redesign, then test each sequence and document the result. On networked systems the documentation follows ANSI/NEMA C137.9 configuration reporting, which is also what utility programs look for when a controls project claims savings.

The recoverable range is meaningful. DLC's 2017 study found networked controls on an LED system average about 47% additional lighting energy savings, with roughly 70% of projects saving 30% or more, and commissioning quality is a major driver of where a building lands. Our NLC design & commissioning service starts with a feasibility memo that tells you what's recoverable before you commit to anything. If the fix overlaps with an incentive, what's still funded in 2026 is worth a look.