Guest Editorial

By: David Parrett, director of product marketing at Cortet, a firm specializing in smart building IoT technologies

If you’re considering a move to networked lighting control, or you’ve already begun roughing in the project scope, you may be wondering: Is fixture-level control or area-based control the best choice?

This question is important for anyone who manages the lighting design of a building, as well as for utility efficiency program managers who are planning energy efficiency programs for commercial buildings.

To be clear, I won’t be delving into what the lighting industry commonly refers to as Luminaire Level Lighting Control (LLLC).

LLLC provides not only the fixture-level control but also integrated occupancy and ambient light sensors. Rather, this blog will discuss control of one or many luminaires. The conclusions below are also applicable to LLLC, but project economies get an even greater imbalance with the added costs of sensors for each fixture.

Fixture-Level vs. Area-Based Control

It’s important to know that there are several approaches to manage a luminaire installation with wireless controls in a commercial building and that most buildings will likely be served by blending these approaches.

So, let’s talk through the differences between them, and the pros and cons of each.

Area-Based Approach

Area-based control is accomplished when multiple luminaires are wired to a single switch or wireless fixture adapter.

In a wiring sequence commonly referred to as “daisy chain,” all the luminaires attached to the control adapter will operate in an identical manner.

However, this doesn’t mean that this approach keeps them from participating in whole building control, as network lighting controls allow for area-based controls to be included in larger zones virtually.

As you may have guessed, there are a few pros and cons for this type of design:

PROS

•  Satisfies most situations. The area-based approach is good enough for most spaces, since it meets design needs at a reasonable value sharing one control adapter across many fixtures.
•  Simplifies configuration. This method also reduces complexity with fewer end nodes to find and configure.
•  Retrofits with ease. In the case of a retrofit, it offers the ability to swap out a switch and control an entire bank of lighting.

CONS

•  Retrofit labor cost. In a retrofit situation, installers may need to run control wires, which adds labor cost to the equation.
•  Less control. The area-based approach results in a loss of control for individual “spots” of light, and instead creates “pools” of light.
•  Less future-proof. If the layout of the space changes in the future, it’s much more difficult to reconfigure the lighting design.

Where it Makes the Most Sense

The area-based approach makes the most sense in a bigger and more heavily trafficked space such as ballrooms, hallways, classrooms or storage areas where large pools of light are perfectly acceptable, and where individual luminaire control would be a waste of time. Plus, these types of spaces generally will not require extensive reconfiguration or adaptation over time.

Now, let’s visit the other type of lighting design approach.

Fixture-Based Approach

Fixture-based control is accomplished when each luminaire is wired to a single fixture adapter.

Network lighting controls allow for fixture-based controls to be included in larger zones virtually, but the luminaires maintain an ability to be controlled individually.

Of course, there are a few pros and cons on this type of lighting design as well:

PROS 

•  Straightforward installation. Fixture adapters are installed at each fixture, so control wires do not need to be installed between luminaires.

•  Reconfiguration ease. As the building’s layout or needs change over time, these types of control systems can be easily updated. It’s not uncommon in a tenant situation to have to change offices, whether adding cubicles or moving walls. If you have control over every fixture, you can use software to change the zones very easily.

CONS

•  Cost. While individual fixture control is an attractive element, the downside is the excessive cost if it’s not completely necessary. From a value standpoint, this is the least economical option.
•  Start-up and Commissioning. A fixture-level approach means you have many more devices to configure, and this can take time and money if it’s not necessary for your scenario.

Where it Makes the Most Sense

When deciding to install a fixture-based approach, consider the density of fixtures and the activity beneath them. While an area-based approach may be better in an open-office plan, individual offices may do better with individual fixture control. Common spaces like lobbies and break rooms are always best when planned for area control when you need to illuminate all or none. In more fixed spaces that tend to evolve, you may want individual fixture control.

There’s No One Correct Approach

When you need to decide which approach to take for your building or facility, know that one way is not necessarily better than the other.

Instead, consider how you can tailor the approach to your specific scenario. After all, you may choose to have greater control with a fixture-level approach in individual office settings, and an area-based approach in the hallways and lobby.

Different solutions within different spaces in a single building make more sense and lessen the cost burden.