Electric Lighting + Luminaire Level Lighting Control

I. Energy Savings & Satisfaction

With electric lighting using roughly 26% of a building’s energy, implementing energy efficient measures to reduce energy consumption is a great way to offset the economic and environmental consequences. Although significant lighting energy savings have been achieved over the past decade through the adoption of efficient ballasts and lamps, leveraging more efficient technology such as LED luminaires and advanced wireless control systems can lead to a significant reduction in energy consumption from the current baseline. A comprehensive report put together by Alison Williams, Barbara Atkinson, Karina Garbesi, and Francis Rubinstein of Berkeley National Lab synthesizes energy-savings data from 240 saving estimates found in over 88 papers and case studies. The collected data was categorized into daylighting strategies, occupancy strategies, personal tuning, and institutional tuning. They were able to provide best estimates of average energy savings potential for occupancy, daylighting, personal tuning, institutional, and when multiple strategies are employed simultaneously. They found that the highest energy savings potential occurred when utilizing more than one method to reduce the energy consumption of your lighting system.

Luminaire-level lighting controls (LLLCs), which incorporate several technologies such as occupancy sensing, daylight harvesting, and task tuning into individual luminaires connected via a wireless network, can produce significant energy savings. A study by Wei et. al., found that by utilizing advanced lighting controls to reduce energy consumption through occupancy sensing, daylight harvesting, institutional tuning, and task tuning savings up to ~64% can be achieved. With installation costs lower than traditional controls due to the wireless capabilities, these new systems have the potential for greater market adoption.

Due to the potential cost and energy savings, Snyder et. al. at the Lighting Research Center at Rensselaer Polytechnic Institute conducted a study on how various parameters impacted LLLC savings. They investigated the sensor’s field of view, delayed time until shut off or dimmed-state, number of luminaires in a single group, and whether fixtures should dim or turn off when no occupancy is detected. Overall, they found an average savings of 43% when using LLLCs compared to manual controls. They also found that changes to the parameters had significant impacts on the overall savings and even occupant satisfaction. With this in mind it is important that designers find a balance between occupant satisfaction and maximum energy savings.

With significant savings demonstrated, the US government  contacted the Pacific Northwest National Laboratory (PNNL) to conduct a separate study within US government buildings. Richman et. al. compiled a report after conducting in-field evaluations for five different advanced control LED lighting systems. These evaluations occurred between November 2015 to September 2017 and were meant to provide data and information to help inform those responsible for energy use and savings at commercial facilities – not a direct comparison between systems. In addition to evaluating the systems, they also conducted pre- and post-retrofit surveys with building occupants and installers. Overall they found average energy savings to be around 66% and general satisfaction with system to be around 84%.

An additional study by Myer and his team demonstrate similar findings. They conducted an in-depth evaluation of five advanced lighting control systems in a working office environment. The case study was designed to evaluate the capabilities of these advanced technologies and highlight their positive and negative attributes, instead of simply comparing one product with another. The evaluation was not only concerned with the energy savings performance, but other critical aspects of the system such as occupant satisfaction, installer experience, and overall system operation. The case study found: that the systems achieved an average energy savings of 63%, installers found the installation on par or easier than traditional lighting, and occupants expressed over 70% satisfaction with the systems.

(shackelford) In 2020 at least 28% of all lamps and luminaires installed utilize LED technology, a stark increase from 2013 in which only 2% utilized LED technology. Retrofit approaches that integrate LED lamps and fixtures with networked controls, daylight dimming, or even advanced shading systems lag in comparison – leaving significant savings on the table. An experiment by Shackelford et. al., sought to make a case for more integrated, packaged retrofit solutions, by quantifying energy savings from various retrofit approaches that include: LED fixtures, advanced lighting controls (daylight dimming, task tuning, occupancy), advanced shading systems, and changes to the lighting layout. Overall, they found that doing integrated-systems retrofits saved over 80% of energy consumption compared to individual component retrofits that saved around 30%.

Mahić and their team were also interested in retrofit opportunities as LLLCs can be easily integrated into manufacturer retrofit kits. This study investigated whether LLLCs, when applied as a one-for-one (1:1) retrofit solution, can provide lighting energy savings and lighting quality that is comparable to more comprehensive Networked Lighting Control (NLC) systems, which tend to require a more complex installation. Mahić et. al. concluded that LLLC systems are a cost-effective retrofit solution that does provide comparable performance to an NLC system.

II. Personal Control of Lighting System

The comprehensive report put together by Williams et. al. found that the best estimates of average energy savings potential are 24% for occupancy, 28% for daylighting, 31% for personal tuning, 36% for institutional tuning, and 38% for multiple approaches. With LLLCs capable of taking advantage of personal and institutional tuning, it is clear that users will welcome this technology as a way to boost savings and improve satisfaction with their interior environments.

The aforementioned study by the PNNL also demonstrated high levels of user satisfaction. They found that users really appreciated the way LLLCs improved the overall experience of the office environment. They noted the  smooth transition between light levels when the space is occupied versus unoccupied, which lended itself to a more comfortable environment. Also of note was the ability to adjust the lighting based on specific tasks. This level of customization allowed users to work environments that fit their individual needs.

Similar to what was experienced by users in the PNNL studies, the study conducted by Mahic et. al. found that users highly valued the ability to manipulate their overhead lighting to fit their specific needs. This feature was only afforded once they installed a 1:1 retrofit with integrated LLLCs. Due to the granular nature of LLLCs (meaning there is a control on each individual light) the lights are able to better respond to environmental changes such as daylight and occupancy to enhance energy savings. 

III. Technology Integration

In addition to demonstrating the energy-saving capabilities of LLLCs, the study by Wei et. al. also highlighted their cost-effectiveness. With regards to new construction and major renovation scenarios with the much lower incremental installed project costs (close to $1/ft2), the incurred costs of LLLCs are much lower. With paybacks ranging from 3 to 6 years, adding wireless advanced lighting controls to lighting projects is a compelling opportunity in new construction and major renovation. In retrofit situations the implementation of LLLCs is much more attractive due to significantly lower installation costs compared to traditional networked lighting control systems that require significant wiring and additional components. These findings are also in line with the study conducted by Mahić et. al.

In addition to energy savings and  ease of installation, the potential to integrate with new technology provides exciting opportunities from a business operations perspective. Michelle Davidson conducted an evaluation of a warehouse case study where an advanced lighting control system was installed and highlights the significant impact a lighting control system can have on the entire operations of a business. Despite the 200,000 sf facility being only 3-years old, its lighting fixtures were consuming over 1.3 million kWh each year. With the implementation of LED fixtures and an advanced lighting control system, the facility was projected to save roughly 500,000 kWh per year, however, since 2013 the building has averaged an annual consumption of 300,000 kWh – exceeding their savings projections. The lighting control system has also enabled the company to monitor space utilization, which ties into their HVAC system to optimize heating and cooling schedules. The lights are also able to track equipment usage, which has improved maintenance schedules and improved the efficacy of their operation. In sum, as technology continues to advance, lighting controls offer a unique opportunity for businesses that extend beyond energy savings.

IV. References

Primary Research

• Snyder, Jeremy. 2020. “Energy-Saving Strategies for Luminaire-Level Lighting Controls.” Building and Environment 169. Elsevier Ltd. doi:10.1016/j.buildenv.2018.10.026.
• Shackelford, Jordan, Mathew, Paul, Regnier, Cynthia, and Walter, Travis. 2020. “Laboratory Validation of Integrated Lighting Systems Retrofit Performance and Energy Savings.” Energies (Basel) 13 (13). United States: MDPI AG: 3329. doi:10.3390/en13133329.
• Myer, Michael. 2018. “Evaluation Of Advanced Lighting Control Systems In A Working Office Environment”. Gsa.gov. https://www.gsa.gov/cdnstatic/Applied_Research/PNNL_Evaluation_Advanced_Lighting_Controls_11-2018.pdf.
• Richman, EE, and McIntosh, JA. 2018. “Advanced Lighting Control System Performance: A Field Evaluation Of Five Systems”. Designlights.Org. https://www.designlights.org/default/assets/File/Lighting%20Controls/DLC_Advanced-Lighting-Controls_Final-Report_PNNL.pdf.
• Mahić, Alan, Jeff Kline, Dale Northcutt, and Kevin Van Den Wymelenberg. 2020. “Luminaire Level Lighting Controls Replacement Vs Redesign Comparison Study”. Neea.Org. https://neea.org/img/documents/LLLC-Replacement-vs-Redesign-Comparison-Study.pdf.
• Williams, Alison, Barbara Atkinson, Karina Garbesi, and Francis Rubinstein. 2011. “A Meta-Analysis Of Energy Savings From Lighting Controls In Commercial Buildings”. Energy Technologies Area Berkeley Lab. https://eta.lbl.gov/sites/default/files/publications/a_meta-analysis_of_energy_savings_from_lighting_controls_in_commercial_buildings_lbnl-5095e.pdf.
• Davidson, Michelle. 2016. “Case Study: Iot Lighting System Cuts Energy Costs, Improves Productivity”. Network World. https://www.networkworld.com/article/3099682/case-study-iot-lighting-system-cuts-energy-costs-improves-productivity.html.
• Joy, Wei, Francis Rubinstein, Jordan Shackelford, and Alastair Robinson. 2015. “Wireless Advanced Lighting Controls Retrofit Demonstration”. Nextenergy.Org. https://nextenergy.org/wp-content/uploads/2018/03/GSA_Wireless-Adv-Lighting-Control-Retrofit-Demo_Apr-2015.pdf.