Resource · Existing Buildings

Get more out of the building you already have.

Buildings drift. Controls get overridden, schedules slip, equipment fights itself, and energy quietly climbs. Retro-commissioning and monitoring-based commissioning are how you find that lost performance in an existing building — often with low- and no-cost fixes that pay back fast.

RCx, re-Cx, and MBCx — the difference

Retro-commissioning (RCx)

A systematic tune-up of an existing building that was never formally commissioned — investigate how systems actually run, find and fix operational issues, and optimize.

Recommissioning (re-Cx)

The same process for a building that was commissioned before — a periodic re-check to recover performance that has drifted over the years.

Monitoring-based Cx (MBCx)

An ongoing, data-driven approach — continuous monitoring flags faults and drift as they happen, so the building stays tuned instead of decaying between projects.

Existing Building Cx (EBCx)

The umbrella term utilities often use for RCx/MBCx work — and the label under which many incentive programs fund it.

Where the data comes in

Monitoring-based commissioning is where Bluefin Intelligence comes in. Instead of a one-time snapshot, live telemetry from the building's systems lets us spot faults, scheduling problems, and energy drift continuously — and verify that fixes actually stuck. It turns commissioning from a one-and-done event into a performance you can prove over the building's life.

When it pays — and when it's required

Retro-commissioning is worth a look when energy bills are creeping up, occupants complain about comfort, maintenance is reactive, or a building simply hasn't been tuned in years. It's frequently funded by utility incentives (see incentives), and for federal buildings it can be required — EISA 2007 §432 obligates agencies to evaluate covered facilities and implement recommissioning on a recurring basis (see requirements).

Own an existing building?

Let's find the performance it's leaving on the table.

Tell us about the building and what's prompting the look — rising bills, comfort issues, or a required evaluation — and we'll scope a retro-commissioning or monitoring approach.

Frequently asked

What is retro-commissioning?

Retro-commissioning (RCx) is a systematic process that investigates how an existing building's systems actually operate and corrects issues — often low- and no-cost operational fixes — to recover lost performance and energy efficiency.

What's the difference between RCx and MBCx?

RCx is a point-in-time tune-up. Monitoring-based commissioning (MBCx) adds continuous data monitoring so faults and drift are caught and corrected on an ongoing basis, keeping the building tuned over time.

How much can retro-commissioning save?

Savings vary by building, but RCx commonly targets meaningful energy reductions through operational fixes with a short payback — and utility incentives can offset the project cost. We scope the opportunity for your specific building before you commit.

Is retro-commissioning ever required?

Yes — for federal buildings, EISA 2007 §432 requires agencies to evaluate covered facilities and implement recommissioning/retro-commissioning on a recurring basis. Some utility and local programs also expect it.

Can a utility fund retro-commissioning?

Often, yes. Programs such as SRP's Retrocommissioning, PSE's Existing Building Commissioning, and Energy Trust of Oregon's existing-building incentives fund RCx/MBCx work. See our utility incentives page.