Post Date: 08/13/21
Converting to LED can be a complicated process. The previous two articles in this series on converting to LED lighting have focused on the costs and benefits of converting from halogen to LED replacement lamps and everything you should know before you switch. Now, we’ll focus on the benefits of using integrated LED fixtures.
Before diving in, it’s important to understand how integrated LED fixtures differ from other kinds of lamps. While halogens and replacement LEDs are mounted into fixtures, integrated LED fixtures include the light source (or LED). As a result, the source is not interchangeable, and when the source degrades, the fixture needs to be replaced in its entirety. However, having one manufacturer responsible for all aspects of fixture design and fabrication provides distinct performance and quality benefits.
This part of the LED series will take an in-depth look at some of the benefits of integrated LED fixtures.
Benefits of Integrated LEDs
Compared to LED replacement lamps, Integrated LED Luminaires provide long-term technological stability, lower risk of system incompatibility, better quality control, longer lifespan, higher output, and enhanced controls.
Technological Innovation versus Programmatic Stability
Before the advent of LEDs, the lighting industry benefited from fairly slow product cycles. This resulted in a very stable technological milieu in which change occurred at the rate of decades. With the introduction of LED technology, developments in lighting technology assumed the pace of electronic product cycles. This means that every other year, there are significant transformations in the technological architecture of LED sources.
However, these product cycles are incommensurate with both the lifespan of LEDs and with that of the building infrastructures into which they are installed. Can you imagine changing out every luminaire in a building every two years?
Rapid product cycles offer vast opportunities for innovation, and the range of new technologies that are more efficient, more powerful and more interconnected are a testament to the kinds of innovation occurring in the lighting industry today. However, technological changes in lamp technology may not align with existing controls and luminaire infrastructures. This can result in an array of aberrant behaviors that make relamping LED replacement lamps problematic.
Integrated LED luminaires remove this risk by providing a stable technological infrastructure that speaks to the design intent of the space over long periods of time. With LM70 ratings sometimes in excess of 75,000 hours, an integrated LED solution can provide up to 20 years of continuous service, or more, depending on usage.
The choice between LED replacement lamps and integrated LED luminaires often comes down to a choice between programmatic stability and technological variability. For spaces with the potential for different programs with different performance requirements, keeping pace with technological innovations might be desirable. For spaces with a fixed, long-term program, where consistency in lighting performance is more desirable, an integrated LED solution may be preferable.
In any lighting installation, there are a large number of variables that contribute to the overall success of the project, including compatibility between the source, the driver, and the control system. When implementing an LED replacement lamp solution, fixture manufacturers only have control over the driver. This leaves two points of incompatibility that are unaddressed: first, incompatibility between the driver and the source, and second, that between the source and the control system. Any incompatibility can result in aberrant behavior, like flickering, failure, or poor dimming performance.
Depending on lamp architecture, it is also possible that the performance of optical media, like linear spread lenses, color shifting gels, louvers, and baffles can be compromised. All optical media depend on how light is propagated to ensure performance, but with the source unknown, ensuring performance becomes problematic. In some instances, optical media may not be available at all, due to the thermal capacity of the lamp, and the thermal performance of the fixture.
Some halogen lamps, like an MR16 GU 5.3 base lamp, require a power supply (for a Halogen lamp, this is called a “transformer”). This converts line voltage to the required input voltage of the lamp. Most legacy power supplies are rated for comparatively high wattage (like 75 watts for the MR16 lamp described above).However, LED lamps require very low wattages. For example, a 7-9 watt LED replacement lamp may replace a 50 watt Halogen lamp.
The comparatively low wattage requirements of LED replacement lamps can cause issues. Since the original power supply for the fixture is designed around the larger load requirements of Halogen lamps, when the load is much lower, the transformer may have difficulties registering it. This typically occurs during dimming, and can result in flickering or an abrupt transition to off.
For line voltage luminaires, like PAR30 and PAR38 fixtures, this should not pose an issue, although the standard best practice is to check with the lamp manufacturer to assess dimming compatibility when dimming is involved.
With integrated LED fixtures, ensuring long-term compatibility between drivers, sources and control systems, as well as optical media, becomes much easier. This is because the fixture manufacturer provides both the light source and the power supply, and if the control system is known, can ensure performance of the lighting equipment. Many controls manufacturers even provide testing and diagnostics for luminaire manufacturers seeking to ensure the performance of their fixtures. As a consequence, there tends to be much less risk with integrated LED fixtures than with LED replacement lamp fixtures as a long-term lighting strategy.
Higher Lumen Output
Whether you are converting an existing space to LED, or designing a new build, performance of the lighting environment will be one of the primary factors in specifying a fixture or lamp. While many LED replacement lamps list an equivalent Halogen source (such as 50 watt MR16), these listings rarely reflect actual equivalencies. For example, while a typical 50 watt MR16 Halogen source produces approximately 800 lumens, many LED replacement lamp “equivalents” produce on average half as much light (around 400 lumens). Similar performance disparities can be found in larger lamps, like PAR30 and PAR38.
Depending on application, this kind of light loss can have significant negative impact on a lighting design, resulting in comparatively dark environments. If an LED replacement lamp solution is preferred, the only means of increasing light levels would be to add more fixtures. This has its own challenges, including cluttered ceilings and cost escalation.
By comparison, using the example of a 50 watt MR16 Halogen lamp, an integrated LED solution in the same form-factor can produce up to 1600 lumens at 24watts. To match an integrated LED solution would require up to four LED replacement lamp fixtures at 9 watts / lamp. In some instances, it is even possible to replace multiple fixtures with a single integrated LED solution across multiple conditions requiring multiple outputs.
For example, before converting to LED, MoMA used a combination of MR16 and PAR38 fixtures in its low and tall galleries, respectively. Both were replaced by the C71 and C72, whose range of output is broad enough to function in ceilings between 12’ - 24’, depending on lighting requirement.
Increased Control and Enhanced Performance
In today’s market, advanced controls, like DMX, Dali, and 0-10v, are becoming much more prevalent. These types of systems respond to the desire for more nuanced (sometimes fixture-by-fixture) control. In some instances, this takes the form of integration into building management systems and sensor networks for increased efficiency, or to respond to Human Centric design paradigms that include tunable white or other types of specialty fixtures.
However, most LED replacement lamps are only compatible with ELV (trailing edge) or MLV (forward phase) phase dimming systems. As a result, they are not compatible with advanced control systems without a phase adaptive module. Furthermore, most LED replacement lamps only dim to between 5% - 10% initial output, and there are relatively few tunable white LED replacement lamp options. Many of the latter have been developed for the residential market, and rely on wireless connectivity using phone or tablet-based applications. As such, these types of solutions may not be ideal for large-scale deployment (in an office or other public venue), especially when compatibility with complex building management systems is in question.
Conversely, integrated LED solutions are not only compatible with advanced control systems (in most instances), but based on the system in question, it is possible to source components based on specific performance needs. This means that integrated LED luminaires can be accommodated to a building’s control environment to respond to input from sensor networks, enact timed scenes, dim to dark (0.1%) or off, and/or shift color temperature based on time of day. Depending on the system, it may also be possible for individual users to control their local environment in ways that meet their preferences in terms of color temperature and brightness.
Choosing the Right Lighting Solution for the Project
While there are no simple rules for choosing between LED replacement lamps and integrated LED solutions, there are at least some guidelines. Perhaps the most important is to approach retrofits and new builds from the position of project requirements, and avoid the “future trap” of a hypothetical world filled with better technology that suddenly makes the designed solution outdated. If the design is sound, whatever new technology is lurking around the corner won’t matter - you’ll still have the best lighting solution for your space.
The truth is that technology is not the primary driver of great lighting, and focusing too much on upcoming technological innovations can set artificial boundaries on design. This doesn’t mean that project requirements can’t stimulate innovation - they can, and frequently do, but this innovation tends to be grounded in current technological paradigms, not in a theoretical future state whose inevitability remains questionable. The potential of future technology should not negatively inform decisions regarding the best lighting infrastructure for the present.
There will be instances in which an LED replacement lamp infrastructure is preferrable. There will also be instances where assurances related to compatibility with advanced controls, expanded functionality (tunable white, deep dimming), output and efficacy, and long-term stability in the lighting environment will recommend an integrated LED solution. Some of these drivers are incredibly important, especially if the design intent is aligned with sustainable design certification (like LEED), or wellness (like WELL).
It is also important to understand that employing LED replacement lamps is a temporary solution, and that while LED replacement lamps can have L70 lifespan ratings up to 35,000 hours, they will eventually need to be replaced. The rate at which they will need to be replaced will be determined by hourly usage over time. This aspect of LED replacement lamps is both good and bad.
The fact that an integral solution will last a long time only represents the fact that the original design intent will persist.