July 15, 2025
Making Sense of Lighting-HVAC Integration in Buildings
Author: Craig DiLouie, LC, CLCP is education director for the Lighting Controls Association
A practical breakdown of tools, benefits, and design considerations from Craig DiLouie
In February 2025, the DesignLights Consortium (DLC) released a new resource to facilitate integration between networked lighting controls (NLC) and heating, ventilation, and air-conditioning (HVAC) systems. The NLC-HVAC Integration Toolkit includes tools and guidance applicable to new and existing construction projects. The toolkit’s goal is to support maximized energy savings with integration by ensuring clear project team communication.
“Many commercial buildings unintentionally waste energy by conditioning unoccupied spaces because their HVAC systems lack occupancy sensors,” said Levin Nock, Senior Technical Manager, DLC. “A lighting retrofit can solve this problem when the new NLC system provides occupancy data to the BAS. NLC-HVAC integration helps save energy, reduce pollution, and meet the Building Emissions Performance Standards by conditioning spaces only when needed.”
Integrating lighting control and HVAC systems saves energy.
DLC research has shown that NLC systems can generate, on average, 48 percent lighting energy savings. By integrating the lighting control system with the HVAC system, up to 30 percent HVAC energy can be saved, making investment in NLC systems more attractive.
HVAC systems serve building occupant by maintaining a set temperature in spaces while exchanging indoor air with fresh outdoor air.
The system may be a constant air volume (CAV) system, in which the fans can be switched On/Off but fan speed remains constant, or a variable air volume (VAV) system, which may entail either fans able to run at various speeds to modify airflow or VAV boxes that control louvers to increase or restrict airflow.
In many commercial buildings, HVAC systems deliver space conditioning and ventilation regardless of whether the space is occupied. If occupancy is consistent and predictable, this is generally satisfactory. If occupancy is variable, however, energy is wasted conditioning unoccupied spaces. If a VAV HVAC system is able to respond to occupancy, it can condition the space only when the space is in use.
HVAC energy savings can be achieved via occupancy sensors.
Occupancy sensors change the lighting state based on whether a space is occupied via a control signal and are most effective when installed in spaces with variable occupancy.
By sharing occupancy signals with the HVAC system, the occupancy sensors can trigger occupied-standby mode in properly aligned HVAC zones. In this mode, the HVAC system reduces or completely shuts off airflow and increases setpoint temperatures in the unoccupied zone, resulting in energy savings.
The control signal may be distributed via dry contact closure, in which an analog signal is distributed via low-voltage wiring to a thermostat or VAV box. Alternately, digital communication from an NLC system to the HVAC system via a building automation system (BAS) can be employed.
NLC solutions are well-positioned for HVAC integration.
The NLC system may include an integration communication layer on top of its system architecture. At this layer, the NLC system uses wired Ethernet cabling or wireless communication to integrate with cloud-based applications and/or other building systems like a BAS. Once integration is established, the building automation software can be programmed to operate in occupied-standby mode based on the occupancy signals.
NLC system architecture with a direct BAS control network interface connection. Image courtesy of the DLC.
Ideally, the installed occupancy sensors for lighting will be of a proper density and placement for effective response. If the NLC implements luminaire-level lighting controls (LLLC), in which sensors are embedded in each luminaire, highly detailed occupancy information becomes available, though careful programming is required to consolidate this data.
“An NLC system offers powered, networked, and evenly distributed positions for sensors throughout the ceiling of a building,” Nock said. “These include occupancy sensors and potentially additional sensors for CO, CO2, etc. Additionally, the system includes a wired or wireless digital network to collect all the occupancy data. If LLLC is deployed, the luminaires can deliver extensive digital occupancy data to an HVAC system to support an estimate of the occupancy level within each HVAC control zone beyond a simple binary of occupied or vacant.”
Larger projects with a BAS, VAV HVAC system, and HVAC zones serving spaces with variable occupancy that align well with lighting control zones are optimal candidates for integration. If a BAS is not deployed, contact closure integration can be explored as an alternative. In smaller buildings lacking a robust BAS, for example, advances in wireless thermostats are expanding opportunities for integration.
In new construction, integration of the lighting control and HVAC systems can be realized through appropriate collaboration and thoughtful design. In existing construction, integration can be more challenging. Recent energy codes now require occupied-standby mode operation in certain space types that can benefit from lighting occupancy sensors sharing space occupancy information with the BAS or HVAC system.
In existing buildings, the project might ideally begin with an LED lighting upgrade that incorporates an NLC system to offset high energy costs and possibly qualify for utility incentives. The additional energy savings that can be achieved through the NLC system and NLC-HVAC integration can make the project more cost-effective and attractive to the owner.
“Upselling a lighting retrofit from manual controls to NLC can be challenging,” Nock said. “NLC-HVAC integration offers a powerful justification for NLC in buildings where it can save substantial whole-building energy using existing BAS and HVAC systems.”
Integration is inherently complex, necessitating good project team communication and an integration champion. Integration projects require collaboration among building owners and managers, electrical/lighting engineers and contractors, and mechanical/HVAC engineers and contractors.
“Each building system has its own level of technical complexity, so combining multiple systems is a complex process,” Nock noted. “The HVAC, BAS/BMS, and NLC systems all need to work together, so the people designing, procuring, installing, configuring, and operating these systems need to work together. With good planning and careful coordination, this process can go smoothly.”
As buildings become more interconnected, successful integration will depend less on technology and more on communication, planning, and cross-disciplinary teamwork.
The Lighting Controls Association is a council of the National Electrical Manufacturers Association that provides education about lighting control technology and application, including articles, videos, design awards, news, resources, and Education Express, a free, 24/7 series of online courses covering everything from technology to design to commissioning.
