You can't optimise what you don't measure

Every building has an energy bill; very few have an energy picture. A monthly total from the main incomer tells you what you spent, not where, when or why — and without those three, every efficiency conversation is guesswork with a spreadsheet. The route out is measurement, and your building management system is already most of the way there.

Break the total apart

The first move is submetering: splitting consumption by end use — heating, cooling, ventilation, lighting, small power — and by area where it's useful. Meters on M-Bus or Modbus feed straight into the system, which turns them from numbers on dials into half-hourly profiles you can interrogate. The moment consumption is broken apart, causes start owning their costs: the chiller that never quite shuts down, the floor that runs a full weekend timetable for a security guard and a photocopier.

Build a baseline you can trust

Raw comparisons mislead — this January against last January says as much about the weather as the building. Correcting consumption for degree days and occupancy gives you a fair baseline, and a fair baseline is what makes savings provable rather than anecdotal. It's also your early-warning system: consumption drifting above the weather-corrected expectation is often the first visible symptom of a control fault, showing up on a graph weeks before anyone raises a comfort complaint.

Where to look first

Three profiles do most of the diagnostic work. The overnight base load — everything running at 2am has decided it doesn't need permission, and some of it is wrong. The weekend profile — a Saturday that looks like a Tuesday is a schedule problem hiding in plain sight. And simultaneous heating and cooling — meters climbing together in mild weather usually means systems fighting, the most expensive stalemate in building services.

None of this requires new plant. It requires meters connected, data trended, and someone looking with intent — measurement first, then tuning, then proof against the baseline. That sequence is the difference between hoping a building got cheaper to run and knowing it did.