Controls Can Be the Bigger Upgrade: How Networked and Luminaire-Level Lighting Controls Work, and What They Save
Most first-generation LED retrofits were one-for-one swaps. Pull the old fixture, hang an LED fixture, and leave it on the same wall switch, breaker, or time clock. That captured the drop in connected load, but it left the other half of the opportunity alone: running the lights only as bright as needed, and only when someone’s there.
In a second-generation retrofit, controls can be the bigger savings measure. They also depend on something many first-generation fixtures can’t do well, which is dim smoothly and continuously.
The four control strategies, and how their savings combine
Lighting controls save energy in four main ways.
High-end trim (task tuning). You set each fixture’s or zone’s maximum output to what the task actually needs. New LED systems are typically designed with extra initial output to allow for lumen depreciation, so trimming to the design light level saves energy from day one. The DLC notes that capping output at 70% to 80% of maximum can save 20% to 30%, often without occupants noticing (DLC Lighting Controls Best Practices). Across the studies it reviewed, the DLC found trim savings of 21% to 36% (DLC, Valuing Dimming).
Occupancy and vacancy sensing. Empty zones dim to a low setback level or turn off. How much this saves depends on zone size, the time delay, and the setback level.
Daylight harvesting. Photosensors turn electric light down in sidelit and toplit zones as daylight comes in.
Scheduling and demand response. Time-of-day profiles, plus shedding load during utility peak events.
A common mistake in savings estimates is simply adding the percentages. Each strategy acts on the energy the others leave behind, so they combine multiplicatively:
Total savings = 1 − (1 − Trim savings) × (1 − Occupancy savings) × (1 − Daylight savings)
Illustrative example: 20% from trim, 30% from occupancy, and 15% from daylight gives 1 − (0.80 × 0.70 × 0.85) = 52.4%, not the 65% you’d get by adding them up. Using the multiplicative method keeps your estimate honest.
What the field data shows
In a 2017 study, the DLC analyzed hourly energy data from 1,200 control zones in 114 commercial buildings with networked lighting controls (NLCs), and estimated average savings of 47% (Lighting Controls Academy). Results varied widely from site to site, and they didn’t follow a consistent pattern by building type (Minnesota Department of Commerce). That’s the argument for modeling savings from your building’s measured operating profile instead of borrowing an average for your building type.
Networked controls vs. luminaire-level controls
The two main approaches differ in where the sensing and decision-making happen.
With networked lighting controls (NLC), remote sensors and controllers group fixtures into zones defined in software.
With luminaire-level lighting controls (LLLC), every fixture has its own occupancy sensor, daylight sensor, and controller, and the fixtures are networked together for grouping and management.
In a Northwest Energy Efficiency Alliance (NEEA) study, the University of Oregon tested four LLLC systems and one NLC redesign in an 891-square-foot office space. The LLLC systems saved 50% to 74% from the controls alone, and the NLC redesign saved 67% (EC&M). Treat those numbers as indicative, not typical. It was one small test space, and the article itself says the room favored LLLC over the NLC design. The principle still carries over: because every fixture can act as its own zone, LLLC offers the finest control, which is why we think it’s worth evaluating for high-bay spaces where occupancy varies aisle by aisle.
What the driver has to support
How well controls perform comes down to the driver and the control interface.
0–10 V analog dimming is common and inexpensive, but it only works one way. The fixture receives a dimming level and reports nothing back. How well it dims depends on the driver’s dimming curve and minimum level.
Digital addressable control (DALI-2) communicates both ways and addresses each fixture individually. D4i drivers can report active energy and power, operating data, and diagnostics (DALI Alliance). That supports measurement and verification (M&V) and predictive maintenance.
Wireless mesh and integrated sensor nodes avoid pulling new low-voltage control wire. In an occupied building, that can decide whether a controls retrofit is practical at all.
SSL V6.0 doesn’t favor any protocol. It sets a minimum dimming range, 20% for most indoor Standard luminaires and 10% for Premium, and requires Premium luminaires to meet a DLC controls category (DLC SSL V6.0 / LUNA V2.0).
Savings beyond lighting: HVAC
The sensors in an NLC or LLLC system also produce a detailed map of where people are in the building. A 2023 DLC report found that sharing lighting-control occupancy signals with HVAC systems can save up to 30% of HVAC energy use (Green Building News). Treat that as a ceiling, not an expectation. It depends on the building automation system actually using the occupancy data, and on how the HVAC zones line up with the lighting zones. Where it works, it turns a lighting project into a whole-building project.
The costs and risks of controls
Controls aren’t free to own, and a fair comparison includes what they need after installation:
- Savings depend on trim levels, time delays, and sensor placement being set correctly. Budget for commissioning, and for recommissioning after layout or schedule changes, because settings drift and people override them.
- Recurring fees. Some networked platforms charge software, cloud, or licensing fees. Include them in the life-cycle cost.
- A networked lighting system is another connected system in the building. If it connects to the building network, the cloud, or the building automation system, have your IT or security team review how it’s segmented, updated, and accessed before it’s installed.
- Occupant acceptance. Setback levels and time delays that are too aggressive lead to complaints and overrides, which erase savings.
Energy codes
Energy codes keep adding control requirements. ASHRAE/IES Standard 90.1-2022, for example, lowered the wattage threshold that triggers daylight-responsive controls to 75 W in the primary sidelighted zone and 150 W in the secondary zone (ASHRAE). Which code edition applies depends on your jurisdiction and the scope of the work. A design that’s ready for controls helps you avoid paying for a second retrofit later.
Where controls tend to pay back fastest
- Warehouse and distribution high bays with intermittent aisle traffic
- Manufacturing with variable shift patterns
- Schools, gyms, and multipurpose rooms that are used on a schedule
- Parking structures and exterior areas with long, quiet overnight hours
- Offices with hybrid occupancy and large sidelit zones
Next step
LED Sales Team can model your facility with and without controls, using measured occupancy data and the multiplicative savings method, so you can see both cases side by side before you decide.
