I hear the same question from building managers every week: “We’ve already switched to LED — what else can we do?” The answer, consistently, is controls. Smart lighting controls in commercial office buildings are delivering 30-40% energy savings on top of what LED alone provides. And unlike a lot of efficiency claims, these numbers hold up in real-world Australian installations.

Let me walk through the technical detail of how these savings break down, what systems are involved, and what the implementation actually looks like.

The Baseline: LED Alone Isn’t Enough Anymore

Switching from fluorescent to LED typically delivers a 40-60% reduction in lighting energy consumption. That’s significant, and for buildings that haven’t made the switch yet, it’s still the first priority.

But here’s the thing: a building running LED panels at full power for 10 hours a day across every zone is still wasting a lot of energy. Those panels don’t know that the meeting room on level 3 has been empty since lunch. They don’t know that the perimeter offices are flooded with afternoon sunlight. They don’t know that the cleaners left at 8pm and the lights are still blazing at midnight.

Smart controls address all of these scenarios. The Green Building Council of Australia now expects sophisticated lighting controls as baseline for any Green Star-rated building, and the energy performance data backs up why.

The Three Pillars of Smart Lighting Control

Meaningful energy savings from lighting controls come from three core strategies, each contributing independently and compounding when used together.

1. Occupancy and Vacancy Sensing

This is the biggest single contributor to energy savings. Modern occupancy sensors use a combination of passive infrared (PIR) and microwave detection to determine whether a space is actually in use.

The key distinction most people miss: there’s a difference between “occupancy sensing” (lights turn on when someone enters) and “vacancy sensing” (lights must be manually switched on, but automatically switch off when the space is empty). Vacancy sensing consistently delivers higher savings because it prevents lights from activating for brief, transient occupation — someone walking through a corridor to the kitchen, for instance.

In a typical office environment, occupancy-based control saves 20-30% compared to a manually-switched LED installation. The savings are highest in spaces with intermittent use: meeting rooms (often empty 50-60% of the working day), breakout areas, bathrooms, corridors, and storage rooms.

Real numbers from a Melbourne CBD office tower I reviewed recently: 23 meeting rooms fitted with vacancy sensing reduced their combined lighting energy by 41% over 12 months. That’s not a theoretical model — that’s metered data.

2. Daylight Harvesting

Daylight harvesting uses light level sensors (photocells) to measure the amount of natural light entering a space through windows and skylights. When natural light is sufficient, the system dims or switches off artificial lighting in the affected zones.

The technical implementation matters here. A properly calibrated system uses closed-loop photocell sensors mounted on the ceiling, measuring reflected light at desk level. This compensates for variable conditions — cloud cover, time of day, blinds position — in real time.

The energy savings depend heavily on building orientation, glazing type, and floor plate depth. As a general rule:

• Perimeter zones (0-4.5m from facade): 40-60% savings during daylight hours
• Mid zones (4.5-9m from facade): 15-25% savings during daylight hours
• Core zones (>9m from facade): Negligible benefit from daylight harvesting

For a typical Australian office with reasonable glazing, daylight harvesting across the perimeter zone contributes an additional 10-15% reduction in total floor plate lighting energy.

3. Time Scheduling and Scene Control

The third layer is automated scheduling. This includes after-hours sweep-off (all lights automatically off at a set time, with manual override available), zone-based scheduling that matches lighting to actual building use patterns, and scene control that adjusts light levels for different activities.

A conference room doesn’t need 400 lux when people are watching a presentation. A hot-desking area at 30% occupancy doesn’t need every zone lit. Scene control allows these adjustments automatically.

The Australian Government’s Energy Efficiency Exchange provides case studies showing that time scheduling alone typically saves 5-10% on top of occupancy and daylight controls.

The DALI-2 Backbone

All of this relies on a communication protocol between the lighting fixtures and the control system. The industry standard is DALI-2 (Digital Addressable Lighting Interface), and it’s worth understanding why it matters.

DALI-2 allows individual addressability of every luminaire. Each fitting has a unique address on the network and can be independently controlled — dimmed, switched, queried for status, and grouped into zones. This is fundamentally different from older relay-based switching, where entire circuits are either on or off.

The practical benefit: you can create and modify lighting zones in software, without rewiring. When a tenancy layout changes — and in modern offices, they change constantly — you adjust the control zones on a laptop, not with an electrician.

DALI-2 also supports bidirectional communication, meaning the system can query each luminaire for operating hours, power consumption, and fault status. This enables predictive maintenance — replacing failing drivers before they fail catastrophically.

Putting the Numbers Together

When you combine all three strategies in a typical 5,000 square metre office floor:

Strategy	Energy Saving	Annual Saving (est.)
LED upgrade (baseline)	50% vs fluorescent	$30,000
Occupancy/vacancy sensing	25% additional	$7,500
Daylight harvesting	12% additional	$3,600
Time scheduling	8% additional	$2,400
Total with controls	Combined ~70% vs fluorescent	$43,500

These are conservative estimates based on Sydney electricity pricing of approximately $0.30/kWh and standard BCA-compliant office lighting density.

The controls hardware and commissioning typically adds 30-40% to the cost of a basic LED retrofit. For our 5,000 square metre example, that’s roughly $40,000-60,000 on top of the LED luminaire cost. At $13,500 per year in additional savings from controls alone, the controls investment pays back in three to four years.

Common Implementation Mistakes

A few things I see go wrong repeatedly:

Poor sensor placement. Occupancy sensors need clear line of sight to the areas they’re monitoring. Mounting a PIR sensor in a corner behind a column creates blind spots. It sounds obvious, but I’ve seen it on multiple sites.

Daylight sensors not commissioned properly. Out-of-the-box calibration is never right. You need to commission daylight sensors on a clear day and an overcast day, adjusting setpoints for each zone. Skipping this step means the system either dims too aggressively (complaints from occupants) or not enough (wasted energy).

Ignoring the user experience. If people find the controls annoying — lights going off while they’re sitting still at their desk, for instance — they’ll override the system. Use sensors with appropriate hold times (15-20 minutes for offices, 5-10 minutes for bathrooms) and ensure manual override is accessible.

Not monitoring after commissioning. Install the controls, commission them, and then… never look at the data again. The best performing buildings review their lighting energy data quarterly and fine-tune settings. Behaviour changes, tenancy layouts shift, and seasonal daylight patterns vary. Set and forget doesn’t work.

The Bottom Line

Smart lighting controls aren’t optional anymore — they’re where the remaining energy savings live. If your building has LED but no controls, you’re leaving 30-40% of potential savings on the table. The technology is mature, the protocols are standardised, and the payback periods are solid.

Start with occupancy sensing in intermittent-use spaces. Add daylight harvesting on perimeter zones. Layer in scheduling for after-hours control. And make sure it’s all running on DALI-2 so you can adapt as your building’s needs change.

The numbers don’t lie. Controls are where the money is.