Retro-Commissioning & Controls Optimization, Office Tower
Chronic tenant complaints and rising energy cost traced to control sequences, terminal units and a mis-set plant — corrected without replacing major equipment.
- Approach
- Retro-commissioning first
- Major equipment replaced
- None
- Terminal units repaired
- Dozens
- Complaints
- Sharply reduced
What made it hard
Ownership had been quoted a central plant replacement to solve persistent tenant comfort complaints and climbing energy cost. The plant was mid-life and, on inspection, mechanically sound.
The real problems were distributed and invisible from the front end: sequences that had drifted through years of manual overrides, failed terminal unit actuators and sensors, simultaneous heating and cooling on multiple floors, and static pressure and supply temperature setpoints locked at values nobody could explain.
How we executed it
We functionally tested every major piece of equipment and a large sample of terminal units, comparing actual behavior against the documented sequences rather than trusting the graphics.
Sequences were rewritten and reset strategies implemented for supply air temperature, static pressure and chilled water. Failed actuators, sensors and control valves were replaced, overrides cleared, and minimum airflows corrected. Air and water balance were verified afterward rather than assumed.
Everything was trended before and after, so results were measured rather than claimed.
What the owner got
Comfort complaints dropped sharply and HVAC energy consumption fell substantially — at a fraction of the cost of the plant replacement ownership had been prepared to fund.
The plant replacement was deferred with a documented condition assessment and a capital plan for when it is genuinely due.
Bring us the hard one
Occupied buildings, no shutdown window, a survey finding with a deadline, a plant nobody wants to touch. That is the work we are built for.