Parts 1 and 2 of this series discussed the sluggish adoption of LED technology in schools and the dim prospects for fluorescent lighting. This final part addresses the LED choices school facility personnel are considering and the new tradeoffs they face.
Three primary LED replacement options are available for linear fluorescent installations: replacement lamps, retrofit kits, and new LED luminaires (see Figure below). Replacement fluorescent lamps are often referred to as tubular LED or “TLED” lamps, and Underwriters Laboratories (UL) has defined three types of TLEDs — Type A, Type B, and Type C. Others might refer to them as, respectively, “plug and play,” “ballast bypass,” and “external driver.”
LED retrofit kits are installed into the fluorescent luminaire housing and replace the existing electrical and optical components. New LED luminaires are used to replace the entire existing fixture, including the housing.
New luminaires and Type B TLEDs were the most common LED options installed at the 30 schools PNNL visited over the past year. Maintenance staff favor TLEDs due to their simplicity, despite safety concerns and issues around lighting quality. On the other hand, schools appreciate new luminaires’ updated look and efficiency, even as some have struggled to maintain them without replaceable components. In addition to output and color decisions, schools need to balance cost, quality, and future maintenance when assessing their upgrade options. So, how do the choices compare?
Lighting quality
Three aspects of lighting quality merit attention from schools considering upgrades from fluorescent lighting: light output, color, and flicker. Well-designed and constructed TLEDs, kits, and luminaires can provide both the quantity and color of lighting appropriate for schools. With quality products available in all LED upgrade types, a suggested best practice is to visually evaluate one or several LED solutions. Comparison can be an effective way to evaluate options and identify unpleasant surprises before committing to a large-scale upgrade.
Three aspects of lighting quality merit attention from schools considering upgrades from fluorescent lighting: light output, color, and flicker. Well-designed and constructed TLEDs, kits, and luminaires can provide both the quantity and color of lighting appropriate for schools. With quality products available in all LED upgrade types, a suggested best practice is to visually evaluate one or several LED solutions. Comparison can be an effective way to evaluate options and identify unpleasant surprises before committing to a large-scale upgrade.
School decisionmakers also need to evaluate flicker performance. Type B TLEDs are raising concerns about flicker, which can pose health and behavioral risks for school populations. In one school that PNNL recently visited, a few teachers reported that they turned the lights off as much as possible due to discomfort, although the specific cause was not identified.
Due to reports from installers and initial lighting quality measurements in the field, PNNL tested 28 Type B TLED lamps in a laboratory setting with discouraging results: 22 of the products flickered at rates worse than old fluorescent lamps operating on magnetic ballasts. Literature on 11 of the products claimed low or no flicker, but these Type B lamps varied in measured performance, which highlights how challenging it can be to select high-quality products. Generally, other LED options measured by PNNL in schools did not exhibit flicker at levels similar to Type B TLEDs. Watch the “Flicker Demonstration” video at https://www.energy.gov/eere/ssl/flicker-demonstration for a short explanation of how to identify flicker.
The economics
TLEDs offer the lowest cost in terms of initial materials. LED retrofit kits usually cost more, and new LED luminaires typically have the highest cost, although these upgrade categories vary greatly with some very affordable options available. Installation costs are generally the lowest for Type A TLEDs, as these simply install in the existing fixture without rewiring. Type B and C TLEDs require some rewiring that may result in labor costs comparable to retrofit kits or new luminaires.
In terms of operating cost, new luminaires are likely the most efficient option as they are optimized for the size, thermal performance, and directional light output of LEDs. Compared to fluorescent, new LED luminaires can reduce the connected lighting load by up to 60%, while TLEDs operating on fluorescent ballasts can expect to reduce the lighting load by about 20%.
Schools should consider how lighting controls could increase savings and introduce flexibility into classrooms. Facility personnel often noted that teachers appreciated the ability to adjust light levels. New luminaires, retrofit kits, and Type C TLEDs are the most compatible with advanced controls; however, some Type B TLEDs now offer networking capabilities and other control features.
Ongoing maintenance
Lighting maintenance is an important consideration when upgrading from familiar fluorescent lighting. Fluorescents can be replaced and maintained by cleaning staff, and standardized replacement lamps, ballasts, and sockets are readily available, at least for now. LED options check some (but not all) of these boxes.
Who takes care of new LED lighting after initial installation? What needs to be replaced? Are replacements available, and are they compatible? The maintenance of different LED options varies, as shown in the accompanying Table.
Type B TLEDs feature an integral driver in the tube, which simplifies maintenance to one component and eliminates compatibility challenges. Compatibility between components used with Type A or Type C TLEDs has yet to be standardized. Type C TLEDs generally operate with drivers from the same manufacturer, while Type A TLEDs lack the broad compatibility of the fluorescent lamps they replace and can perform poorly when operated with some fluorescent ballasts. What happens when a compatible ballast is no longer available? Products with compatibility challenges may not be the best solutions for schools, especially when completing an upgrade over time.
Type B TLEDs may appear to be the easiest solution to maintain. Nevertheless, many Type Bs on the market currently are prone to flicker and may pose safety hazards if improperly rewired or relamped. During the installation of Type B TLEDs, existing ballasts are removed, and line voltage is connected directly to the lamp holders — either to one end or both. A single-ended TLED saves wiring time but poses a shock risk if the luminaire is not de-energized and a person touches the exposed end of a partially installed lamp. Double-ended TLEDs reduce the risk of shock because the ends of the lamp are not energized until they both are fitted in the socket.
In addition, accidentally installing a fluorescent or a Type A TLED can create a fire hazard due to the lack of an appropriate power supply. Labeling of modified luminaires is required, but the wording, size, and placement of these labels vary. Examples of variable product labeling are shown in the Photo. During interviews, some school facility personnel mentioned that only electricians or trained maintenance staff change TLEDs due to these concerns. Increasing awareness of the risks as well as separating stock and limiting to one wiring configuration moving forward can greatly reduce the risks.
Retrofit kits, flat panels, and new LED luminaires may not be serviceable, so the entire product will need to be replaced at the end of life. Even where drivers are serviceable or replaceable, a compatible option will need to be available. Whether just a driver or the entire luminaire needs replacement, an electrician will have to do the job. Half of the schools PNNL interviewed did not have an electrician on staff, and many struggled to hire electrical contractors. Talk of “right-to-repair” and replaceable LED components is heating up, but widely standardized LED lighting systems similar to fluorescent will not be available for some time.
Looking ahead
Based on PNNL’s conversations with schools, the change to LEDs is underway. Upgrading lighting can reduce energy consumption and operating costs and refresh the look and feel of the school. So what can schools do to prepare for an upcoming conversion?
Evaluate options in pilot classrooms. Evaluate everything from the installation process itself to the lighting performance. Good quality lighting should provide a comfortable amount and color of light for tasks without producing glare and should adequately light people’s faces to support communication. Poor lighting with glare or flicker can lead to headaches, eye strain, and other negative effects.
Think long-term, and make a plan. Fluorescent lighting has served schools for a long time. What does maintaining an LED system look like for the next 30 or 40 years? While TLEDs seem like an easy solution today, relying on fluorescent luminaires and other components will become more challenging in the future. Compare the up front and ongoing costs for each LED option and consider developing a “standard” lighting solution that can be repeated over time, space by space, or school by school.
Do you have experiences or successes of your own to share? Reach out to our team at [email protected].
