With roughly 40% of the average facility’s electrical load dedicated to lighting, according to EPA estimates, the benefit of increasing your lighting system’s energy efficiency is clear.
What’s not as clear, however, is the process of choosing the best lighting control system for your building from the large variety of options on the market. Start with these eight tips to find the system that best meets your needs.
1) Decide What Your Building Needs
Understand the influence that the building type exerts on its lighting needs and gather input from building occupants. For instance, a school has fairly basic requirements that might include dimming for AV presentations and daylight harvesting when the shades are open. Study the facility’s current layout, room and task types, and occupancy patterns to answer questions like:
- How far does daylight penetrate? Are you in an open office with large windows allowing daylight to spread or is daylight only entering a series of perimeter offices?
- Is a building management system already in place?
- Which occupants (if any) would benefit from dimming or other task-tuning
- Which areas are unoccupied for long stretches of time?
- Are there spaces where you can’t risk the lights going off if the motion sensor isn’t
triggered, such as an
Be involved from the beginning to alert the installer to
access limitations and other challenges that will determine the scope of the retrofit.
Also ensure that your prospective system meets local lighting codes. If code compliance is your primary goal, you may be able to satisfy requirements with occupancy sensors or daylight harvesting alone, says Kelly Eidson, director of product management for lighting and controls for Schneider Electric, a manufacturer of energy efficiency, security, and automation tools.
“Figure out what you’re trying to do first,” Eidson explains. “If you’re just trying to meet energy codes, you can use occupancy sensors to turn the lights off when no one’s in the space. Or you can go all the way up to a complex system with an energy management platform to look at your savings and see where the highest consumption is.”
2) Assess the Current Lighting
Start by determining what types of lighting are currently installed. Many systems are compatible with a wide spectrum of legacy lighting, not just the ubiquitous LEDs, so you’ll likely be able to find a system that allows you to keep your existing lamps.
It’s always advisable to use more energy-efficient lighting when you can, but if a lighting retrofit isn’t in the cards this year, simply gaining more control over the existing lighting will go far toward improving your facility’s efficiency.
“If something fails and you’re replacing a light or a bank of lights, it’s a great opportunity to invest in a system that can provide better energy efficiency,” says Jason Choong, chief solution architect and vice president of product management for Daintree Networks, a wireless lighting control platform developer. “Ultimately, the facilities manager needs to make an economic decision, but these options are available, so seriously consider them before going for the quickest and cheapest way to solve the issue.”
3) System Size Matters
For a smaller solution, local occupancy sensors will deliver a significant level of savings for a relatively small price, Choong advises. Dimming sensors and switches are similarly simple to install. Complement these with a basic panel-based scheduling control to further boost the savings that are possible with a simple setup.
“When the space is vacated, you can set the light level to 20% instead of zero or have the light only come on when someone enters,” Choong says. “You could combine it with an occupancy control that’s auto-off/manual on so that you’re encouraging people to make a choice to not turn on the lights, especially when there’s light coming in during the day.”
More advanced control systems may offer demand response capabilities, shade control, daylight harvesting, task tuning, and other functions requiring networked controls to communicate with each other. An energy management component allows you to institute a measurement and verification (M&V) plan that includes the ability to view usage trends, spot underperforming fixtures, and generate reports.
“It’s relatively simple to add some level of M&V because an advanced system knows which lights are on and what the dimming levels are, so you can estimate the energy used,” Choong explains. “You can also introduce power meter circuits that measure the power consumption of each fixture, which allows accurate monitoring down to the fixture level.”
Advanced products are frequently scalable, so you can start small by installing a granular control system for one floor or even one tenant and expand it throughout your whole building or campus as your budget allows.
“Ask vendors how their systems scale,” recommends Barry Weinbaum, president and CEO of Lumenergi, which develops lighting and energy management systems. “If I start small and grow to a bigger implementation, do I knock myself out of this product and into one that supports a larger configuration, or do I have something that can expand?”
4) Balance First Cost vs. Potential Savings
The more granular the control, the steeper the savings, according to a review of lighting control strategies by Clanton & Associates. The study, which was conducted for Daintree, compared estimated savings in two model 1970s-era office buildings, both around 25,000 square feet with 2-foot by 4-foot acoustical grid ceilings. To account for climatic and labor cost variations, researchers used local data from Boston and Los Angeles for the sample buildings.
Predictably, the most advanced setup achieved the highest degree of savings – 49% below the ASHRAE 90.1-2007 energy baseline (see page 35), as well as the lowest lifecycle costs (see page 38). It featured a wireless full dimming system incorporating photocells, occupancy sensors, and dimming ballasts to provide dimming capabilities and occupancy sensing in all major spaces.
However, a system relying on addressable ballasts (which assigns digital addresses to all ballasts and connects them with network cabling) achieved nearly the same results at 47% below ASHRAE’s baseline. This option outperformed the wireless partial dimming scenario (dimming in areas with daylight and wireless switching control in non-daylight and support spaces), which resulted in 31% below baseline.
The Clanton & Associates team attributed these results to the similar distribution between daylighting and occupancy controls between the addressable ballasts and wireless full dimming scenarios, while the wireless partial dimming example did not utilize daylight sensors to provide tuned high-end trim dimming in response to natural daylight. A separate study by Daintree found similar savings when comparing the energy-saving potential of each individual control type.
Basic lighting control systems typically cost less than $1 per square foot installed, often with payback less than two years. Even the most complex systems with energy management, monitoring, and other advanced capabilities typically range from $1-4 per square foot installed with payback periods of two to five years, adds Michael Jouaneh, manager of sustainability and energy standards for lighting control product developer Lutron Electronics and a member of the enLIGHTen America Task Force created by the National Electrical Manufacturers Association (NEMA). The task force advocates for energy-efficient lighting updates.
“These systems pay themselves back because you get a lot of energy savings and people in the building are happier and more productive,” Jouaneh explains. “Buildings often have too much light in the space for the tasks people are working on – some spaces are lit even though they’re empty, and many of those spaces are daylit with sunlight and yet electric lights are left on. You can get a nice energy savings and a good payback from upgrading your lighting and controls. It’s the lowest-hanging fruit to obtain energy savings in commercial buildings.”
5) Consider Incentives and Perks
Does your local utility offer a demand response program? If so, consider participating – the financial benefit can shorten the payback period on an advanced system that’s capable of managing demand response events.
“You can put rules in the building management system to automate demand response,” says Mike Malone, vice president of sales at Crestron Electronics, which produces building system automation and control solutions. “When the signal from the utility is received, it triggers different steps that are built into the control processes. For example, I need to drop 10% of the power, so I’m going to dim the lights by 15% and bring the cold water temperature up by 5%, but I’m not going to change the temperature of the server room.”
Also factor in non-monetary perks, such as those that come from integrating lighting with other building systems. Some control products can be added to your BMS so that you can manage lighting alongside water and other resources. By incorporating lighting data into a larger network, you can achieve outcomes ranging from additional energy reduction to extra benefits for the security system.
“Imagine that at the Facebook data center, someone is doing maintenance on a server. They scan their security card and Rows 2 and 3 light up because that’s what they have access to,” explains Greg Campbell, CTO of Lumenpulse and developer of the Lumentalk control system, which operates by sending digital signals along existing electrical wires.
“They do their maintenance, but then go into Row 4 without permission. The lights go on because they’re on occupancy sensors and trigger the question of why they were in Row 4 when they only had access to 2 and 3. That functionality you essentially get for free.”
6) Wired or Wireless?
Wired and wireless controls each have distinct advantages. Which is right for your building? Review the as-built drawings of your facility to see where wiring is routed and understand the impacts that other systems and building materials can have on your project’s outcome, particularly if you’re installing wireless controls into a facility that already has other wireless networks using the same frequency.
“You can strategically place wireless controls anywhere throughout the building and get the same type of control as a wired system or very close,” says Tokey Arojojoye, president and CEO of NGN Consulting, an IT consultancy that also offers lighting control programming. “Bigger buildings have so many wireless networks that you run the risk of interference, and some have steel beams that limit your wireless range. If you go wired, there’s no risk of interference.”
7) Prep for Installation
Along with the as-built drawings, develop accurate, thorough plans for each area.
“Provide the installer with information on the routing of the wiring, how the lights will be controlled, and how you need the new lighting controls to control the use of your lights,” recommends Marcelo Banderas, senior applications engineer for Siemens’ Low & Medium Voltage Division.
The more detailed the plans are, the easier the installation will be, says Mitch Lazarus, principal director of Lighting Control Consultants, Inc. For each area, note items like gang boxes, where new sensors and switches go, and so on.
“Plan your work and work your plan,” says Lazarus. “It might say that for the first floor, office 101, north wall, there are three gang boxes. Load 1 is the ceiling lights, Load 2 is a half hot outlet, and Load 3 is for the desk light.”
Don’t forget to brief occupants who will be affected by the installation. Give notice of work that will be performed during business hours and explain what to expect, from task tuning to plans to dim common area lighting.
“Communicate what will happen,” Choong says. “Educate people and say ‘There’s going to be some disruption. Sometimes the light levels will be lower than you’d like, but if you’re not happy, talk to me.’ If all you do is introduce the new controls and suddenly their lights are darker, you won’t have the mindshare of your tenants.”
8) Confront Challenges Before and After the Retrofit
As the retrofit begins, establish a schedule and expectations with the installers, recommends David Weigand, director of sales, Northwest region, for Encelium, which created the first energy management-specific addressable lighting control system.
“I used to manage the lighting and electrical standards for all of the Starbucks stores, and it was a huge challenge to put in wireless access to all of them,” Weigand explains. “I required all of the installing teams to limit conversations with people in the building. They had to be very polite and wait until someone in the store needed to move out of the area. Establish the scope and parameters of how to interact with that building while the work is being done.”
Throughout the process (and afterward), monitor occupant satisfaction with surveys and a reminder to communicate concerns. Emphasize that the new controls will make it easier to adjust light levels to individual needs. Then, after three to six months, consider bringing the installer back to fine-tune the system’s settings, Weinbaum recommends. A system with data gathering capabilities makes it especially easy to track usage and spot opportunities for additional savings.
“You might have stairwells that are rarely occupied, but you light them all the time, or hallways where people rarely go,” Weinbaum explains. “When your cleaning staff comes in at night, we can set lights to go on and off to push them through their cleaning schedule and make them more efficient. It’s through systems like this that you gain an insight into your building and the ability to save energy you never thought possible.”
Janelle Penny (firstname.lastname@example.org) is associate editor of BUILDINGS.