Working Together
In parts of the country, the new school year used to start with crisp fall days, followed by brisk winters and a few cool months of spring—no air conditioning was needed before classrooms emptied for the summer.
In many places, that era is no more.
As the school year began in September 2025, an independent group of scientists released a report showing that 92% of 246 major U.S. cities now experience summer weather 10 days later into the fall than they did several decades ago. For one in five cities analyzed, it’s at least two weeks later. Compared with the 1970s, for example, summer weather is sticking around 14 days longer in Buffalo, New York; 19 days later in Erie, Pennsylvania, and 23 days later in Presque Isle, Maine, according to Climate Central.
“The rise in cooling demand will likely continue as the planet warms,” states Climate Central’s website, “and schools will need critical building upgrades and face higher operating costs to maintain safe, comfortable temperatures.”
School buildings, particularly in the country’s northern tier, are largely unprepared for this new weather pattern, however. An Edweek Research Center survey conducted in summer 2021 found that, while more than 75% of school district officials in the South reported that their buildings are air conditioned, only 20% of respondents in the North said the same.
What’s more, 41% of districts nationwide need to update or replace heating, ventilation and air conditioning (HVAC) systems in at least half of their schools (about 36,000 buildings), according to a General Accounting Office report. The American Society of Civil Engineers’ “2025 Report Card for America’s Infrastructure" says that GAO finding makes “HVAC repairs the most common infrastructure need across school systems.”
Although less data is available for higher education facilities, anecdotal reports suggest a similar story at colleges and universities. In 2024, eight residence halls at Ohio State University in Columbus had no air conditioning, according to The Lantern student newspaper; 12 of the 23 residential buildings at Iowa State University in Ames lacked air conditioning, Iowa State Daily reported.
As school districts and college campuses address their air conditioning needs, they have an opportunity not only to make buildings more comfortable and amenable to learning, but also to boost and future-proof energy savings associated with HVAC upgrades. The key is integrating heating and cooling systems with networked, controllable lighting.
Lighting paired with HVAC
Overhead lighting is ubiquitous in the ceilings of commercial buildings, including academic facilities. Networked lighting fixtures provide ideal places for occupancy sensors because they offer broad unobstructed coverage, readily available electric power, and easy data transfer over the lighting control network. Networked lighting controls (NLC) equipped with occupancy sensors can detect when building spaces are vacant and then turn off or dim lighting when and where it’s not needed to save energy and related carbon emissions. Research has shown that NLCs can reduce lighting energy consumption by an average of about 50% more than is possible with non-networked energy-efficient LED lights.
On the heels of those findings, the DesignLights Consortium (DLC) commissioned another study, which concluded that even deeper energy savings are possible through integration of controlled LED lighting with HVAC systems. The 2023 report, “Economic Potential of Networked Lighting Controls in Commercial Buildings: Tapping the Added Value of HVAC Connections," showed that pairing lighting controls with HVAC systems to deliver occupancy signals can save up to 30% of the energy used for HVAC and 20% of a building’s total electric energy consumption.
This strategy is especially appealing in the parts of the United States and Canada where efficiency incentives can cover most of the incremental cost of upgrading a lighting retrofit project to include NLC. In addition, lower energy costs aren’t the only financial benefit. When a lighting retrofit with NLC is combined with an HVAC upgrade, occupancy data from the NLC system can significantly reduce the operating expenses of the upgraded HVAC equipment as well.
The DLC’s 2023 study results were released as the technology to enable NLC-HVAC integration has improved. When new AC systems (or heat pumps with AC plus electric heating) are installed in classrooms, for example, thermostats integrated with occupancy sensors can help minimize the new electric load. These smart thermostats are becoming available from multiple vendors.
Communicate and collaborate
Despite the inherent energy saving potential of NLC-HVAC integration, the strategy has been slow to catch on—largely because of the siloed nature of the lighting and HVAC industries. A working group the DLC convened in 2023 reported that a lack of communication between lighting and HVAC professionals is the major hurdle to broader adoption.
As a nonprofit organization dedicated to leveraging lighting, controls and integrated building systems to enable energy savings, decarbonization and sustainability, the DLC set out to change this paradigm. Earlier this year, the DLC released an innovative resource designed to dissolve barriers in communication and improve collaboration between the professional worlds of lighting and HVAC.
The NLC-HVAC Integration Toolkit has five components. The first, and perhaps most important, is a Decision Tree to help building managers and contractors determine whether a project is a suitable candidate for integration and avoid cases where success is unlikely. For example, the strategy generally provides more bang for the buck in larger facilities, especially those with building automation and variable air volume systems. That said, smaller buildings with variable occupancy also may benefit from lighting-HVAC integration. The Decision Tree takes those considering a project through the steps needed to determine whether to move forward.
Other toolkit sections:
- A template of a sample construction integration specification;
- A handbook that concisely describes the basic information that each group involved in an NLC-HVAC integration project needs to know, with a glossary and references to relevant standards;
- A responsibility matrix that presents an integration project in terms of major tasks and indicates which party is responsible for each;
- 18 case studies presenting successful integration examples.
Case studies are searchable by building type and include examples of several educational settings where integration of HVAC and connected lighting systems increased energy savings. They include an elementary school construction project in Bellevue, Washington, as well as retrofits in administrative and academic buildings at the University of Minnesota, the University California Davis and the Long Beach and Carson campuses of California State University.
To date, NLC-HVAC integration has been more feasible and popular on college campuses than in K-12 buildings—partly because colleges and universities are more apt to employ dedicated facility managers and to use building automation systems (BAS).
Campuses have used BAS for decades to help facility operators better manage systems such as HVAC and lighting. Artificial intelligence is starting to help colleges and universities enhance those benefits. A 2024 project at California State University Northridge, for example, used AI software with existing lighting controls to adjust the HVAC system of an office and workspace building based on real-time occupancy data, machine learning models and algorithms. Integrated with the facility’s building automation system, the AI solution reduced total building electricity consumption by more than 15%, reducing usage by nearly 14,900 kilowatt hours and saving almost $3,500 annually.
For now, NLC-HVAC integration is most feasible in facilities with BAS, such as Cal State Northridge’s 10,000-square-foot hall. But advances in technology and increased expertise and awareness are making it a practical strategy for school buildings without BAS as well. And, by bridging the gap between the professional worlds of lighting and HVAC systems, the DLC’s toolkit is designed to keep expanding the integration market.
Intended to fit the needs of an array of professionals, including building management system contractors, engineers and designers, the NLC-HVAC Integration Toolkit is available to download free of charge at https://designlights.org/resources/reports/nlc-hvac-integration-toolkit/.
The DLC developed the toolkit to encourage and facilitate better coordinated projects that yield bigger energy and cost savings in a wider array of facilities. Whether facility personnel have experience with building systems integration or it’s a brand-new concept for them, they can explore this resource and a companion video (https://designlights.org/lighting-hvac-integration/) that leads viewers through the process.
Levin Nock is Senior Technical Manager at the DesignLights Consortium.