Troffers are found everywhere there is a need for economical area lighting. They are commonly used in offices, schools, commercial, retail and public spaces and more. They are available in a number of different dimensions; generally, 2’x4’, 1’x4’, 2’x2’, and 1’x2’. Typically, there is a lens of some sort that is best suited for the intended needs. That lens might consist of a simple plastic lens of a particular design to distribute the light in a desired fashion or even louvers to help place the light in the correct relation to the task, or to simply provide for a lighting effect for some particular application. Even though the lens that is associated with troffers has a tendency to lower the efficacy of the light, troffers fitted with fluorescent lamps – which has been the industry standard for many decades – have set a higher standard for LED luminaries to meet than most other lighting, e.g., typical incandescent lighting. The fluorescent light being used in testing provided more lumens than the LED counterparts could produce, so the decision to stay with fluorescent technology would be a safe decision. That being the case it had been a tough sell for the conversion to LED troffers as the initial cost could still be a concern, especially when considering the number that might be needed in the conversion of a place such as a school or multi story office complex. However, there are now LED troffers and LED tubes for troffer conversion which can compete with the light output from old tech fluorescent troffer luminaries and the overall energy savings are dramatic.
In regard to energy savings, the average energy use for lighting in a typical commercial building is 20% of the total energy consumption of the building. The most popular and economical lighting for such applications has, for decades, been linear fluorescent lights, which have accounted for well over 75% of all the lighting in these buildings. The number of recessed troffer luminaries installed in the United States is estimated to be a total of well over 360 million. The conversion to LED troffers has seen some substantial increase in the past few years but it is estimated that only a mere 1% of the troffer luminaries installed in the United States are LED units. Looking down the road, if the projected market penetration figures come to be, there can be an expected 70% energy savings by the target year of 2035, when it is predicted that troffer luminaries will be able to reach a 75% market share.
Although current fluorescent troffer/linear luminaries might be listed as having a higher lumen output than some LED products, the common lighting design implementation of even many older commercial buildings and work spaces is, and was, to provide more light than standards require. In such cases, the LED output would likely provide very excellent lighting and there would be a good chance that the general lighting afforded by the LED upgrade would increase the overall improvement of the lighting in regard to color rendering and other factors in which LED lighting can outperform fluorescent. Not to mention the buzzing and blinking and maintenance associated with fluorescent troffers/linear luminaries that is not a factor with LED luminaries. The appropriate LED solution for a proposed fluorescent troffer upgrade certainly should be dependent on an assessment of the output of the current lighting to determine that the correct LED applications are implemented.
The advertised output of older units is dependent on age, as all components of the older fixture units, including the mechanical/electrical components, contacts, and connections, do degrade and do contribute to reduction of the advertised output. The greatest contributors to output reduction are dirty and/or old, discolored lenses, and dirty tubes and reflectors. In regard to reflectors, they are necessary with fluorescent troffers because fluorescent tubes emit light in a 360° pattern. On the other hand, LED tubes have a controlled beam angle and a troffer reflector is not necessary for the LED light distribution, but the light pattern of the fluorescent and LED troffers might differ by the time the light reaches the intended area. Good calculations and measurements and a select area mock-up are suggested steps to take to determine correct light levels. Quality should also be a very high consideration as there are LED products on the market which are attractive due to price and those products will quite often have CCT and CRI (color temperature and color rendering) ratings which are not equal to current fluorescent or higher quality LED products. It should be noted that color temperature (CCT) does not, in any way, indicate any sort of quality. However, it could possibly create an unwanted surprise if not visually as expected. Color Rendering (CRI), on the other hand, is surely a barometer of quality, and values in the 80’s are what should be sought. Purchasing products from known and reputable lighting manufacturers is a definite plus when upgrading to any LED luminaries.
The old technology troffer upgrade options include; complete new LED troffers, LED tube replacement of existing fluorescent tubes in existing troffers, and replacement kits. At this point, manufacturers are allowed to self-classify products as a Luminaire, Lamp, or Retrofit Kit, and the definition of each of those categories is up to the manufacturer. So, those options need to be well addressed and considered, as overall quality as well as certain safety certifications may not be met by some products or applications. There is an organization that is establishing guidelines and performance criteria for LED troffer luminaries. The Better Buildings Alliance is that group and is a collaboration between the U.S. Department of Energy and owners, operators and managers of commercial buildings. They provide fact sheets, specifications, and webinars that are related to high efficiency troffer lighting, as well as other energy related building products. The group has established performance criteria which would be advisable to consider. The important criteria include: a warranty of at least ten years; a minimum of 68,000 operational hours with a lumen maintenance greater than 70% of initial lumen output; a minimum CRI of 80; a minimum efficacy of 125 lm/W (lumens per watt).
Prior to any proposed LED troffer upgrade, all the above, along with the potential of contact with health or environmentally unfriendly materials in and around the ceiling plenum are certainly necessary issues to consider. Prior purchase and installation, instruction and product specification sheets for the upgrade being considered should be reviewed to help determine the potential extent of the project.
As always, if you have questions in regard to any of your lighting projects, please feel free to call Polar-Ray at 303-494-5773 to speak with a lighting consultant. Thank you for perusing our web site.