LED renovations and retrofits: Evaluating codes and costs
Clients are asking lighting designers to help them save on energy costs, and replacing fluorescent, HID, or other lights with LEDs is in high demand. Here’s a look at the codes and guidelines that define LED use, including ASHRAE Standard 90.1, California Title 24, Dept. of Energy, and IECC.
- Recognize the impact of various lighting sources on the energy efficiency of a building.
- Know the codes and standards that dictate lighting design.
- Understand the availability of rebates and incentives that may exist for utilization of LEDs.
According to the U.S. Dept. of Energy (DOE), LED lighting can have the greatest potential impact on energy savings in the United States. The DOE estimates that widespread use of LEDs could save the equivalent of the annual electrical output of 44 large, 100-MW electric power plants for a total savings of more than $30 billion at today’s electric rates.
This solid-state lighting technology that uses a semiconductor to convert electricity into light is one of the most energy-efficient and durable lighting technologies today. In fact, LED light sources can be six to seven times more energy efficient than conventional incandescent lights, allowing for significant reductions in energy use. Quality LED light sources can have a service life of more than 50,000 hours, or more than 50 times longer than incandescent lamps and four times longer than compact fluorescent lamps. That is a life of more than 5 years if run 24/7. LEDs are robust, resistant to breakage because of their compact size, and easy to maintain.
Other benefits to LED lighting include:
- Emittance of light of an intended color without using any color filters
- Emittance of light in a specific direction, reducing the need for reflectors and diffusers that can trap light
- Negligible on/off time-full brightness can be achieved in less than a microsecond
- Ideal for uses subject to frequent on/off cycling, unlike incandescent and fluorescent lamps that fail more quickly when cycled often
- Difficult to damage with external shock due to its solid-state components
- Minimal heat radiation, i.e., reduced cooling requirements
- Inherently dimmable
- Comes in a wide variety of styles, colors, and sizes to fit any décor and task
- Availability of retrofit components for numerous luminaire types (retrofit kits shall be UL listed).
With these significant advantages, LED can be a great solution for certain retrofit and renovation applications.
Evolution of LEDs
Even though LEDs currently have many advantages, it took years to optimize this technology and increase its efficacy to today’s average 70 to 100 lumens/W. With extremely high costs, the first use of the visible-spectrum LED more than 50 years ago was limited to applications such as replacement of indicator lamps in displays and appliances. It wasn’t until 2000 that the DOE began funding solid-state lighting research and development, allowing LED technology to develop rapidly with improvements in the use of materials, extraction of more light, and other underlying technical challenges that previously hindered its widespread use as a source for general illumination.
During the LED research and development phase, each manufacturer published lamp life and efficacy values based on its own criteria, resulting in inconsistent performance levels. However, standards were recently developed to allow for accurate comparisons between different manufacturers’ LED luminaires and between LEDs and other lamp types. Some of the critical LED standards established include Illuminating Engineering Society (IES) LM (lighting measurements)-79 and LM-80 standards. LM-79 is a standard method for photometric lighting measurements. LM-80 is a standard method for measuring lumen maintenance, which is used to make useful lamp life projections. Cost analysis and light level calculations are now able to be completed more accurately and consistently, and therefore LED luminaires specified on projects should be compliant with these standards.
As LEDs continued to advance technologically, energy codes were simultaneously revised. In fact, these revisions helped push the implementation of LED sources. For example, when energy codes changed the requirements to a maximum of 5 W/side on exit signs, LEDs become the norm because the incandescent and compact fluorescent types could not comply.
Each new edition of the energy codes establishes more stringent requirements, with California Title 24 energy code leading the way. Title 24 has modified the requirements necessary to comply with the latest lighting power density and controls requirements for replacement projects, which makes LEDs an appealing solution because other lamp technologies cannot easily meet some of these requirements.
The latest 2013 California Title 24 standards, which took effect on July 1, 2014, expanded requirements for photo and occupancy sensors and multilevel lighting controls, both indoors and out, making adaptive lighting the new standard in California. The newest standard also requires many more retrofit and renovation projects to meet new construction standards for lighting than in the 2008 standard. Spaces in which less than 10% of the lighting is being changed out, or buildings in which fewer than 40 ballasts are being replaced are exempt. Otherwise, all new lighting in an existing building must meet not only the lighting power density (LPD) requirements, but also most of the controls requirements (including dimming). In addition, lighting in exterior spaces, such as parking garages, lots, and loading areas, will be required to have occupancy controls with at least one step of 20% to 50% of full lighting power. The wide range of retrofit LED products available today allows for a more economical solution to meet codes without having to replace the entire luminaire.
Other states have adopted various versions of the International Energy Conservation Code (IECC) or ASHRAE 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings. The major changes in lighting for ASHRAE 90.1-2013 include adjusted LPD, more stringent lighting control requirements, and a new table format for determining lighting power and control requirements in individual spaces. Most interior LPD values were lowered. For example, building area method LPDs were adjusted for retail spaces to 1.26 W/sq ft (down from 1.4 W/sq ft), offices to 0.82 W/sq ft (down from 0.9 W/sq ft), and hospitals to 1.05 W/sq ft (down from 1.21 W/sq ft). The other significant changes from the 2010 standard are a new table format for determining LPD allowances using the space-by-space method and minimum mandatory control requirements using either the space-by-space method or building area method.
Similarly, the 2015 version of the IECC has made modifications from the previous released code to include reductions in LPD values and enhanced lighting control requirements. The 2015 IECC continues recognition of the space-by-space method that was re-introduced in the 2012 version as a compliance path along with the building area method, which provides additional flexibility. The IECC space-by-space method is based on ASHRAE 90.1, with subtle differences in space types and lighting power allowances. In the end, the continual trend for reduction in installed lighting power densities makes fixtures with high efficacies, such as LEDs, a viable option, especially for U.S. Green Building Council LEED projects where the goal is an even greater energy reduction below code.
To date, entire facilities can and have been designed completely with LEDs. Code alone can drive the decision to using LEDs. Although this luminaire has a high first cost, it may actually be the most economical choice when taking both maintenance and energy costs into consideration.
High ceiling areas-High ceiling areas require high-bay luminaires that can provide adequate illumination at the work plane height. Common light sources include metal halide, high-pressure sodium, fluorescent, and LEDs. The maintenance costs for lamp replacement are much higher compared to areas with standard ceiling heights due to the necessity of scaffolding or lifts to replace them. By installing LEDs, fewer lamp replacements would be necessary due to their long lamp life. However, LEDs are similar to metal halide and high-pressure sodium lamps in that they maintain a degraded function and still glow past their useful life. Therefore, LEDs should be replaced when this occurs so illumination does not fall below IES recommended levels at 70% of its initial light output.
Continuously illuminated spaces-Current ASHRAE 90.1 and IECC editions still permit security and emergency egress areas to be continuously lit with no controls. In these situations, the use of LED luminaires provides both extensive energy savings and lowest maintenance costs due to their low wattage and high lamp life. In a 10,000-sq-ft space with an average illumination of about 30 footcandles, the LED can provides more than twice the total energy savings over other lamp types.
In addition, NFPA 101: Life Safety Code requires emergency lighting to illuminate egress pathways within 10 seconds upon loss of normal power. In facilities where the backup power source for emergency lighting is a generator, these emergency luminaires must turn to full brightness immediately for a quick and safe evacuation. LEDs, along with incandescent and fluorescent lamps, are great choices for this application, unlike high-intensity discharge (HID) lamps, such as metal halide and high-pressure sodium, which have a long re-strike time and require re-strike lamps that do not provide even distribution.
Exterior-An astronomical time clock or photocell with a time clock has typically been used to meet energy codes for exterior lighting controls. However, as of the 2013 edition of Title 24, ASHRAE 90.1-2010 and 2015 edition of IECC, reduction of light levels (between 40% and 80% for Title 24 and a minimum of 30% for ASHRAE and IECC) is required when certain spaces are not occupied, such as mechanical yards or terraces. Title 24 takes it a step further by requiring motion sensors to be installed on luminaires mounted less than 24 ft above ground in order to reduce light levels in unoccupied areas and automatically turn on when motion is detected from dusk to dawn. Both LED and HID lamp types operate well in colder climates, but the long startup and re-strike times associated with HID hinder this type from being an optimal solution.
LEDs are often considered a potential solution for retrofitting parking lot light poles that contain HID lighting. However, a simple head-for-head replacement on existing poles may not provide similar illumination levels or an acceptable max/min ratio. Light loss factors shall be taken into consideration, but a 400 W high-pressure sodium lamp with 50,000 initial lumens can be 2.5 times greater than one of the highest initial lumen LED replacement head. Therefore, the costs of providing additional light poles would need to be factored into the overall costs analysis if the same amount of footcandles as the existing installation is desired.
Controllability-Adaptive lighting, which is the ability to automatically dim or shut off lighting when not required, provides the opportunity for further energy savings beyond just reducing the total connected load. California’s Title 24 requirements are written around this premise of using energy only when it’s needed. This energy efficiency measure lends itself to installing LED lighting with its instant-on and quick restrike capabilities.
In addition, for LEDs, continuous dimming from 20% to 100% is required. However, linear fluorescents are required to have a minimum of four different illumination levels (20% to 40%, 50% to 70%, 80% to 85%, and 100%) for lamps greater than 13 W. These controls steps could be achieved with either continuous dimming, stepped dimming, or switching alternate lamps within the luminaire. The increased costs for dimming or additional ballasts needed to achieve compliance with fluorescent lamps should be factored into the equation when comparing LED or other lamp types for specification.
Rebates and incentives
While LEDs have a number of viable applications, they have one of the highest initial capital costs and are therefore often eliminated on projects where first cost is the primary deciding factor. However, various rebates and incentives programs exist to lower these initial costs and, therefore, LEDs appeal more to end users than ever before.
Utility companies in California and Illinois, for example, offer a variety of rebates for replacement of existing luminaires with LEDs. Examples range from a few hundred dollars for replacing existing 1,000 W pulse start metal halide lamps with 500 to 750 W LEDs and existing HID outdoor fixtures with 500 to 750 W LEDs, to more minor rebates for replacing interior accent and directional incandescent fixtures with LEDs. Incentives also can be provided for replacing existing incandescent or fluorescent exit signs, and interior and exterior luminaires with LEDs. Additional incentive options may exist for public and nonprofit projects and should be researched accordingly, while utility companies may offer technical assistance and calculated incentives to any facility for replacing equipment to achieve energy efficiency.
Designers should always consult with their project’s local utility providers and state incentives to determine what incentive programs are applicable and best suited for their facility. Some incentives require pre-applications, while others contain certain restrictions that must be considered during the design phase if the incentive is desired.
Although lighting can be considered an afterthought to most designers, it can affect the way people feel, work, and live. And because it is a substantial source of energy consumption, lighting is an essential technology that requires attention in all facilities.
From energy efficiency and longevity to controllability and durability, the benefits of employing LEDs have grown with the evolution of the technology itself. As state-by-state requirements are beginning to dictate higher standards of lighting efficiency, LEDs come to the forefront as a means to achieve them. With continued reduction in first costs due to applicable rebates and improved manufacturing processes, the switch to LED is as compelling as ever for renovation and retrofit applications.
Michael Mar is an electrical engineer at Environmental Systems Design Inc., implementing sustainable and reliable design solutions to various mission critical facilities, high-rise buildings, and large-scale complex developments both domestically and internationally. He is a member of the Consulting-Specifying Engineer editorial advisory board. Robbie Chung is a project manager at Environmental Systems Design Inc. with extensive experience across multiple market sectors including mixed-use developments, high-rise residential/commercial buildings, and educational facilities.