Controls, Energy + Environment

The Horizons of Lighting-HVAC Controls Integration: A Conversation

The Horizons of Lighting-HVAC Controls Integration: A Conversation

By Clifton Stanley Lemon and David Shiller

LightNOW published the story, Here Comes The Lighting-HVAC Integration Tsunami, on October 6th 2023. It generated a number of responses, including the beginning of a longer conversation with LightNOW contributor Clifton Stanley Lemon. The salient points of that conversation are below.


What jumped out at me immediately was your assertion that we can expect a tsunami of technology on controls integration just around the corner. You know controls integration has been a favorite theme of mine for some time, and still is, but I’ve recently changed my mind considerably about this on a number of fronts.

For many reasons I’ll go into below, there will be no tsunami anytime soon. I appreciate your being on it and talking about it, but I’ve been involved in this topic for years, and progress is very slow. I don’t see any evidence of a rapid transition on this, despite several interesting signs, as you pointed out.

The barriers to integration are legion, but probably the biggest is the lack of shared design practices, education, and most importantly, training and certification of integrators. Siloization of all building system trades will linger for a long time, and the disconnect of professions and technical knowledge on both sides of the meter is profound. IMO the best way around this is to train integrators. (Which I plan to work on.)

All of the things that you point out are indeed encouraging, but they don’t necessarily add up to a rapid transition. We can’t predict this transition at all, but if history is any guide, it will very likely take a lot longer that we want it to.


I acknowledge that you probably have more experience in this area, also that all of the obstacles to lighting-HVAC control integration that you mentioned are real obstacles. But my sources indicate that a lot of utility rebate research, interest, and activity are occurring around the subject of lighting-HVAC energy savings potential.


I agree that there is a lot more interest surfacing lately, but from my standpoint the context for this is that its fairly recent. I’ve been on this topic for several years, and have found it difficult to get many people seriously interested in it, or to be able to talk about it usefully from experience.

For clarity, I’ll define “controls integration” as the ability for two building systems, say HVAC and lighting, to share sensor data and operational control in order to optimize energy use. HVAC and lighting are the two building systems that historically use the most energy in commercial buildings, so getting them to talk to each other in a standardized and feasible way is an important transitional step. There are, of course, many other important building systems to integrate into a single system, but this is phenomenally difficult, and we completely underestimate the timeframe it will take to make this happen.


In August 2023, DLC released a report, Future-Proofing Energy Efficiency with Networked Lighting Controls, which calculated energy savings potential for Arizona and Connecticut, specifically. The study found lighting-HVAC control integration could cost-effectively save 10% of commercial building energy consumption in Connecticut, and 5% in Arizona. In both of these cases, the energy savings potential is enormous.

I believe utilities will find rebate programs that incentivize lighting-HVAC controls integration irresistible at a time when basic LED retrofit saving potential is rapidly diminishing, due to socket saturation. My argument is that if rebate programs throw big money at lighting-HVAC integration, market adoption will follow. When LED troffers and flat panels were given larger rebates if they were dimmable, the end result was that large numbers of 0-10V dimmable troffers and flat panels were installed, but the control wires were never installed because of significant costs involved. In such cases, larger rebates resulted in dimming fixture adoption without any additional energy savings from the installation. The rebates spur adoption regardless of whether the adoption is done well or not.


Right, the savings potential at scale is enormous, no question. But energy savings from integration is greatly misunderstood. Integrated controls can ultimately facilitate building-grid connection, load management (reducing the curtailment of energy from renewables is now a crucial problem in California and elsewhere), and resilience. These benefits are far more important than efficiency, but we’ve been so myopically focused on energy efficiency alone that we fail to see beyond the device or beyond the meter. The good news is that when systems integration is successful, it always delivers great efficiency as well – it’s not a tradeoff. The opportunity for HVAC reductions are certainly there as you point out, but this isn’t really the most important reason to integrate.


Large rebates can drive adoption whether done right or done wrong. We both want to see lighting-HVAC integration done well, yielding meaningful economic and environmental benefits, including energy cost savings, carbon reductions, enhanced demand response capabilities, grid resiliency, and more.

After checking with utility rebate experts, I admit that utilities may be a couple years away from widespread implementation of lighting-HVAC integration rebates. However, steps in that direction are occurring, and some in the lighting and controls industries are already positioning for it.

Another driver can be municipal building benchmarking standards that are being implemented in more and more cities. Buildings that don’t meet energy efficiency improvements over time will be fined by the municipality. New York City has a prominent example of these benchmarking requirements with fines for non-compliance.


Well, this brings up something that’s been on my mind for a long time, which is questioning whether rebates actually work at all. One issue is that in California, for instance, all rebate programs have been extremely device-specific: put in one piece of gear (heat pump, LED bulb, efficient washer/dryer, or whatever) and get the rebate. This makes sense from a broad market adoption standpoint, because on the ground, that’s about all owners and contractors can deal with. With “smart” controls you’re dealing with a system, not just components, and that makes it exponentially more complex to calculate impacts and incentivize systems. What are the baselines? What will make owners open to sharing energy use data?


Most of the rebates I’ve heard about that are going to lighting+HVAC control integration are commercial new construction performance rebates, using energy modeling software. This is very limiting, but utilities are desperate for a large new source of commercial energy savings. I don’t know if utilities will get to prescriptive rebates for lighting+HVAC integration, but I suspect they’ll find a way. They’re motivated. It will admittedly take time. I honestly see more opportunity on the commercial side than the residential side. Savings are bigger, owners are more motivated by savings, and advanced controls are more common.

In terms of an example of a complex system receiving prescriptive rebates, I can only point to networked lighting control (NLC) rebates that are already available from many utilities. It could be argued that these rebates haven’t had a significant market impact yet, given the low adoption level of NLCs. However, the utilities have found a way to incentivize complex NLC systems. It’s certainly not a simple widget installation, like a light bulb / lamp.


Integrated controls are playing out in the commercial and residential sectors in radically different ways. Residential and commercial energy use per sector is approximately equal, but distributed over completely different building types (although multi-family residential is a growing category.) So, the scale effects of everything – technology, efficiency measures, incentives, codes, standards, and owner and operating behavior – are very different in each sector.

It’s true that in the commercial sector, savings are bigger, owners are more motivated, and advanced controls are more prevalent. On the other hand, in the residential sector, tech companies are relentlessly developing and selling whole-system products that supposedly can talk to everything in your house. Unfortunately, much of this has already led to ridiculous and unnecessary tech overload that wastes money, time and…energy. I’m hoping for an eventual consumer backlash to this that will force tech companies to make stuff that people really need, and stop with the ridiculous self-driving cars and other useless consumer tech.

There are two or three strong trade groups completely devoted to residential systems integration – of course, they’re servicing billionaire houses where you have two or three server closets just to run your western Jetsons-style palace in Big Sky Canyon in Montana. There’s nothing like this sophistication in commercial systems integration, although I am hopeful that some of the learning, standards, and design practices developed in the residential sector can eventually “democratize” and become more available to Ma & Pa Public for homes for normal people. Again, this will take a lot of time.


Here are two examples of utility sector activity around lighting-HVAC integration:

  1. DLC is planning to release an RFP for a contractor to develop an NLC-HVAC Integration Toolkit, to help people working on NLC-HVAC building automation communicate more clearly with one another.  The Toolkit will include a handbook organized around various roles, project-specific blank templates, efficiency-program NLC-HVAC incentive blank templates, a decision tree to aid in choosing suitable projects, and a list of relevant case studies.
  2. The Northwest Energy Efficiency Alliance (NEEA) is actively exploring approaches for utilities to implement lighting-HVAC integration in the Pacific Northwest. I believe these types of research and investments will lead to utility rebates for lighting-HVAC integration, and then market adoption over time.


Individual building systems have all evolved separately with their own control systems to the point where they’re all very elaborate. We’ve had an engineering holy grail for 20 years to unify them, but it hasn’t happened, and we can’t wait anymore. It’s kind of been a Mexican standoff between lighting and HVAC over who will own the magic black box that runs everything. This is now an irrelevant turf battle. And controls have gotten almost unusably complex.

So this brings up the question…can utilities incentivize appliances and devices that do this? I think yes, and they already have to some degree. We understand incentivizing individual appliances and devices, not complex systems. Network lighting controls may represent the outside limits of what utilities can incentivize, and I’m not sure how successful that has been. I suspect not very successful. We need to examine whether in the long run utility incentives have created or can create the energy transition we need.

Something that we can do now involves sending price and GHG signals from utilities to enabled devices. My original instinct with controls integration, from an efficient engineering standpoint, was to avoid all those separate control points and have one unified controller to talk to all systems. But this looks increasingly untenable – we don’t have the economic will to make this happen, it will take too long. If we mandate that devices must be able to respond to signals from utilities, the path is clear because manufacturers must make it happen, and we can begin balancing the grid sooner rather than later. And in this scenario we don’t need the utilities to incentivize anything because energy efficient operations of appliances and devices is already built into the approved products that use energy. This is an elegant solution!

In summary, two approaches we’ve tried so far – the holy grail of an AI automated black box that runs building systems and energy use “seamlessly;” and utility incentives for integrated control – haven’t worked yet and aren’t likely to work anytime soon at the scale we need to manage both the climate crisis and impending energy shortages. We need to look seriously at totally different approaches

Image: Icons by Freepik & Nhor Phai


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