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Lighting Controls, Revisited

Stan Walerczyk

I was fortunate enough to get some detailed feedback regarding my controls column, Lighting and the Internet of Things. I look forward to even more feedback in the future, whether it be positive or negative.

In my previous column, I made the statement “LED lighting is so efficient and electric bills are so low, that controls are often not cost effective for energy savings.” Liz Jacobs at Intermatic emailed me about that statement.

Jacobs stated:
“That may be the case for some projects, but to add to the discussion, it’s important to note that lighting controls provide other benefits besides energy savings. These include security and safety, convenience, environmental comfort, ambience, and marketing presence, just to name a few.”

For example, my company, Intermatic, has worked with a chain of convenience stores that had previously used manual circuits. Since the stores run on a 24/7 schedule, employees were supposed to turn on the outside lights at dusk. Convenience stores get busy, especially at dusk when much of the American workforce is on their way home and stopping to shop.  So it’s not surprising that employees occasionally lagged behind in turning on lights and stores stayed “dark” longer than they should have. Insufficient lighting was a problem for the safety and security for the stores’ employees and customers.  Lack of lit outdoor signage put these stores at a competitive disadvantage when there were other well-lit alternatives on a busy street.  Shoppers gravitated to well-lit enterprises that visually cued them with lighting that the business is open, safe and inviting.

I emailed her, thanking her for her valuable input and also mentioned that I have seen numerous elementary school classrooms, private offices and some other rooms where burn time actually increased when sensors were installed. This is because before the sensors were installed, people in the buildings were so good about turning lights off when they left, and after the sensors were installed, they allowed the 10 – 15 minute delay.

Jacobs replied:
“Your comment about elementary schools and offices where burn time increases sometimes with post-sensor installation is right on.  I’ve spent time talking with facility guys and contractors at trade shows or distributor customer events where they mention the same, and with some frustration.  No topic is simple it seems.”

“No topic is simple is seems,” is a very appropriate statement.

For example, several building codes, including ASHRAE and California Title 24, mandate occupancy sensors, even in retrofit projects where people are very good at turning off lights manually. So instead of being able to save more KWH other ways, contractors have to buy and install occupancy sensors, which make payback and other financial returns worse, and the customer may not even approve the project. At least in California, since occupancy sensors are mandated in certain applications, there are no rebates for them.

Several other people have told me that advanced controls can really help in multi-tenant office buildings, which are on a common meter. Often the electric bills are split based on square footage and tenants working a normal daytime shift Monday through Friday. Without advanced controls, if people in one company work late and on weekends at lot, the other tenants end up paying for big chunk of that electricity. But advanced controls can detect and record when people enter certain spaces and how long they are there, which allows proper electric billing for after normal hour agreements.

Advanced controls can also improve security. If a security person is informed that an occupancy sensor turns on the lights in a certain room at 2 am on a Sunday, and nobody was expected to be there then, the security person can go to that room.

Lastly, there are occupancy sensors. In addition to turning off lights, they can also reduce air flow in that room, which can reduce heating and air conditioning loads.

The bottom line is to examine each project to see if and which, if any, controls are cost effective, not only for energy savings, but also for other purposes.

Good distributors can really help contractors get the correct items for each job, so end users are satisfied and are not looking for replacements every couple of years. It’s just not a ‘one size fits all’ solution.

Please email your comments and questions to stan@lightingwizards.com.

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