Commercial building energy codes are requiring increasing lighting control criteria with each new revision. In many spaces, strategies must be layered to ensure lighting is used only when needed, where needed, and at the needed output.
Luminaire-level lighting controls (LLLC) integrate these strategies into networked luminaires, streamlining code compliance and installation, adding user functionality and flexibility, and providing a platform for more ambitious networking and data collection. They also provide a simplified path to integrating robust control solutions into upgrades. As the luminaire manufacturer integrates and tests the controls component, the luminaires install normally.
Historically, an inhibitor to adoption of LLLC has been initial cost. An encouraging new study by the Northwest Energy Efficiency Alliance (NEEA) reveals that average costs have been undergoing a steep decline, making advanced controls more attractive for lighting upgrades and new construction.
LLLC and its benefits
For their study, the NEEA defined an LLLC as a lighting control system that is integrated into luminaires and wirelessly networked, enabling luminaires to communicate and transmit data. Sensors and controllers can enact daylight harvesting, high-end trim, continuous dimming, and combinations of these capabilities.
A trend in lighting control, which is reflected in the latest energy codes, is the miniaturization of the control zone. With LLLC, each luminaire operates as its own control zone. This granularity of control zoning maximizes responsiveness of the control system, which typically produces deeper energy savings. According to Better Bricks, LLLC uses 25 to 75% less energy than non-controlled luminaires.
As this approach typically uses less wiring and provides energy code compliance out of the box, installation and commissioning are simplified. Because of the detailed granularity of the control zoning, luminaires can be reconfigured more easily to accommodate space changes. While LLLC can operate at the room level, networking can be expanded to the building level, allowing collected data to be applied to non-energy benefits such as space utilization, asset tracking, and more.
The 2018 and 2021 versions of the International Energy Conservation Code (IECC) recognize the energy-saving utility and comparative simplicity of LLLC by differentiating it among the mandatory control requirements as a streamlined alternate compliance path affecting all installed luminaires.
These model codes define LLLC as a system in which luminaires feature embedded intelligence, occupancy and light sensors, wireless networking capability, and where required, local override switching capability. They require the luminaire to be independently capable of occupancy sensing, dimming to maintain a desired light level, and configurability including dimming set-points, timeouts, fade rates, sensor sensitivity, and wireless zoning.
NEEA studies cost
In January 2021, the NEEA published the 2020 Luminaire Level Lighting Controls Incremental Cost Study. The study was designed to estimate the average incremental installed cost (product plus labor) of LLLC to the end-user compared to LED luminaires with no controls.
As a secondary goal, NEEA also compared the incremental cost of LLLC to luminaires plus controls installed to achieve minimum energy code compliance.
NEEA differentiated LLLC offerings into two major categories:
Clever: These systems satisfy DesignLights Consortium requirements for high-end trim, dimming, occupancy sensing, and light sensing. The luminaires install in a plug-and-play manner and require little or no additional programming.
Smart: These systems build on the capabilities of Clever systems but feature the ability to communicate and analyze energy and non-energy data for various uses such as space utilization, asset tracking, and more.
NEEA also recognized an emerging subcategory:
Clever-hybrid: These systems include a standalone gateway and provide additional capabilities such as monitoring but do not provide the full data collection and analysis capabilities of a Smart system.
The NEEA’s research included interviews of 16 manufacturers and manufacturer representatives and involved collection of 19 project cost estimates based on prototypical office buildings. Cost estimates were itemized for detailed analysis. The result was an estimated average cost per luminaire and square foot.
Table courtesy of NEEA
LLLC costs are declining
NEEA estimated a total average incremental cost for LLLC:
- $49 per luminaire for Clever systems
- $90 per luminaire for Smart systems
- $63 per luminaire for Clever-hybrid systems
Again, this is compared to the average installed cost of LED luminaires without any controls, which served as the comparison baselines.
Image courtesy of NEEA
Based on a 40,000-sq.ft. prototypical office building, the average incremental cost breaks down to:
- $0.58/sq.ft. for Clever systems
- $1.16/sq.ft. for Smart systems
- $0.78/sq.ft. for Clever-hybrid systems
Between 2019 and 2020, NEEA’s analysis revealed:
- 17% decrease in average incremental cost for Clever systems
- 20% decrease in average incremental cost for Smart systems
- No change in average incremental cost for Clever-hybrid systems
Between 2017 and 2020, NEEA’s analysis revealed:
- 28% decrease in average incremental cost for Clever systems
- 16% decrease in average incremental cost for Smart systems
- 21% decrease in average incremental cost for Clever-hybrid systems
Image courtesy of NEEA
Comparing a lighting project complying with energy code control requirements versus one complying with LLLC, NEEA calculated an incremental cost for LLLC:
- 8% higher than a code-minimum project for Clever systems
- 15% higher than a code-minimum project for Smart systems
The NEEA study demonstrates that average LLLC cost is declining over time, making this option more attractive for lighting upgrades and new construction.
For Clever systems, the primary value proposition is installation simplicity, application flexibility, and maximum energy cost savings.
For Smart systems, the primary value proposition goes beyond that of Clever systems by achieving non-energy Internet of Things benefits through data collection and analysis. In new construction, the incremental cost of making the lighting system IoT ready with LLLC for a prototypical office building is an average 15% higher than a lighting system that satisfies code minimums and 7% higher than a basic LLLC system that maximizes energy savings.
Click here to read the NEEA report.