The Real Cost of Ignoring HVAC Optimisation

HVAC is often the single largest energy consumer in commercial buildings. When it drifts out of tune—even slightly—the costs compound every hour of every day. The waste is rarely dramatic; it’s the quiet kind: a pre‑start that begins too early, a deadband that’s too tight, a valve that doesn’t quite close. Left alone, these frictions can add 10–25% to annual consumption without anyone noticing until the bill lands.

Signals of waste

Look for patterns that don’t make operational sense. A rising night‑time base load suggests schedules aren’t biting or overrides are defeating them. Weekend operation in office space is a classic sign of forgotten exceptions. Simultaneous heating and cooling shows up as stable but elevated consumption while comfort appears fine—an expensive stalemate caused by poor sequencing or failed actuators. Drifting or biased sensors will cause systems to “fight” imaginary conditions, increasing runtime with no comfort benefit.

Data makes these issues visible. Plot kWh against occupancy, inspect AHU supply temperatures during unoccupied windows, and compare valve commands with measured responses. You’ll quickly spot the outliers worth fixing.

Fast corrective actions

Begin with schedules: align start and stop to real occupancy and add adaptive logic so plant starts “just in time” and stops early while zones coast. Widen deadbands slightly to prevent short‑cycling and heat/cool overlaps. Implement simple resets—supply air temperature, duct static, and chilled/hot water temperatures—to match load rather than running flat‑out. Finally, hunt down the silent killers: stuck dampers, failed valves, and permanent overrides. Most fixes are configuration, not capex.

Lock in the gains with guardrails: alerts for out‑of‑hours runtime, alarms when setpoints are edited beyond policy, and periodic evidence reports that prove conditions stayed within comfort bands.

Quantify the ROI

Use a simple before/after measurement and verification approach. Select comparable pre‑ and post‑windows, normalise for weather, and report changes in runtime and kWh with confidence intervals. Attribute savings to the specific measures you implemented so finance can see where value was created. In our experience, a focused 30‑day programme consistently achieves double‑digit reductions in HVAC consumption with zero comfort penalties.

Mini case study: A multi‑site HQ reduced weekday runtime by 32% and weekend consumption by 58% by tightening schedules, enabling DCV, and fixing a handful of faulty actuators. Comfort scores improved and maintenance tickets fell, turning a cost exercise into a better occupant experience.