The lighting industry has enjoyed a tremendous boom in available light sources, efficiency and technologies that make lighting retrofits a sure bet when it comes to saving energy. Building owners now have new light sources and lighting controls such as LEDs, compact fluorescent, induction and hi-lumen fluorescent lamps to choose from as well as some of the older “tried and true” technologies that continue to improve and provide cost-effective and efficient alternatives. These include Pulse Start metal halide, ceramic metal halide and HIR halogen lamps, just to name a few. Lighting has also become high tech and shares many components with the mobile electronic devices that are so common in our everyday lives such as cell phones, touch pads and mp3 players. As we all know, today’s newest hi-tech gadget can be tomorrow’s obsolete paperweight. The same can be said about some of the latest lighting technologies available today. At first blush, it’s pretty obvious with the fast pace growth of lighting why some people are still on the fence about retrofitting their old, inefficient and sometimes obsolete lighting in their buildings that continues to drain their energy budgets but still work. There is no sign of the lighting industry slowing down anytime soon, so it’s time to jump in and start saving money on your building lighting. So when is the right time to do a lighting retrofit? What technologies are the best to spend your hard earned dollars on, will it be obsolete after it is installed and will the energy savings really pay back the cost of the lighting retrofit? These are some of the topics that we will discuss in future posts and are usually the first questioned that need to be asked when considering a lighting retrofit project. An experienced lighting designer who is well versed in lighting retrofits, design tools and current lighting technologies will provide the most energy savings and occupant comfort utilizing the right mix of lighting technologies throughout the project.
According to the U.S. Department of Energy, commercial lighting can account for 15% to 50% (median of 35%) of a building’s annual energy consumption. Outdoor lighting is included in that statistic and retrofits in conjunction with interior lighting retrofits can reduce that annual energy consumption by as much as 85%. Outdoor lighting retrofits can be more expensive with a longer payback than interior lighting but have a more predictable payback since they are typically on for 4,200 hours a year and usually on a set schedule from sundown to sunup with little to no human intervention. Outdoor lighting can include retrofitting existing lighting controls, existing lighting fixtures or replacing with new fixtures. For the purpose of this post, outdoor lighting consists of pole mounded site lighting and wall mounted fixtures. Other exterior fixtures I will not be discussing, for now, and that you may encounter are landscaping, monument signs, and billboard lighting. The easiest way to save energy on outdoor lighting is to not have them on at all, but that is not very practical. Since we can’t control when the sun is out and the fact that we need outdoor lighting at our buildings at night for security and safety we must look at what we can control. Controlling how much light and when it is on can result in the fastest return on investment and can often time utilize the existing lighting layout and fixtures. Lighting controls consist of astronomical time clocks, photocells, motion sensors, lighting contractors and lighting control panels. With the advent of LED and dimming HID technologies motion and photocells can now be tied together to dim the output and reduce energy costs even more. For example, as the sun goes down in the evening the outdoor lighting can turn on at a set level of say 25% and increase in brightness as the sun goes down until 100% lighting levels are achieved and then be dimmed down to 50 during non-business hours until a motion sensor detects movement increases the lighting levels then returns them back to 50% after the motion is not detected. A system such as this could save 40% to 60% of energy costs but may not work with existing lighting. Which control system is the right choice depends on the lighting technology used and the use facility. Outdoor fixtures are subject to extreme environmental conditions such as vibrations, wind, sun, extreme temperature swings and physical abuse and therefore any decision about retrofitting the lamp in an existing fixture must take into account the robustness of the lamp source and the fixture housing. For example, a retrofit with a compact fluorescent lamp (CFL) that prefers warmer operating temperatures in a fixture originally designed for an HID source such as mercury vapor or metal halide might not be the best choice if the fixture is installed in an area that sees temperatures below 0 degrees Fahrenheit for more than a few days. Most CFLs are not rated to start below this temperature and light output can be reduced by as much as 50%. Another consideration is lamp compatibility with the existing fixture. The existing lamp base (medium or mogul), operating voltage (120, 208, 240, 277,347,480 VAC, etc.), physical size limits and the type of distribution pattern provided with the fixture can reduce retrofit options or make it impossible to do. In my experience, the most successful retrofit that I have performed are 175-watt mercury vapor HID fixtures which requires the use of now-outlawed ballasts in the United States that can consume approximately 205 watts per fixture. These can be retrofitted by removing the ballast, wiring line voltage directly to the socket and installing a 60-80-watt hi-lumen CFL rated for the appropriate voltage. As mentioned in regards to controls, existing high-pressure sodium, low-pressure sodium, metal halide, mercury vapor or Compact fluorescent fixtures can be replaced with new fixtures employing the latest lighting technologies such as LED and dimming controls for improved energy savings. The retrofit can often reuse the existing mounting hardware, circuiting and in some case can reduce the number of fixtures required for the same amount of light. With the right fixture choice and lighting design energy consumption can be reduced by 50% or more depending on the original fixture.
As mentioned in the outdoor lighting post, according to the U.S. Department of Energy, commercial lighting can account for 15% to 50% (with a median of 35%) of a building’s annual energy consumption. Indoor lighting accounts for a majority of that statistic and also has a more diverse variety of lighting fixture types, lamp types and lighting design requirements. With that being said, a lighting retrofit designer must be well versed in available lighting retrofit options and design tools to make a lighting retrofit successful. The most common and cost-effective retrofits in commercial applications are linear fluorescent lamp(s)/ ballast replacement with hi-lumen lamps and electronic ballasts, de-lamping, retrofit kits and relighting kits. Re-lamping an existing fluorescent fixtures still using older 48” length T-12 lamps and magnetic ballasts can consume as much as 46 watts per lamp (40 watt T-12 with a 2-lamp magnetic ballasts), increase summer cooling costs and reduce occupant comfort due to humming noise and low frequency flickering. This is the easiest retrofit that can provide the quickest payback and can be performed with the existing fixture in place, from the room side of the ceiling and consists of removing the existing lamps, magnetic ballast(s) and installing an instant start or program rapid start ballast with hi-lumen T-8 lamps, such as the 25, 28 or 32 watt super T-8 lamps. For example, a four lamp fixture originally consuming 184 watts can now provide equal to increased lighting levels at 92-104 watts and can eliminate the heating load, low frequency flicker and humming noise of the old lamp/ ballast system (based on 25, 28 or 32 watt hi-lumen fluorescent lamps with a normal ballast factor of 0.89). If we also reduce the number of lamps in this example by de-lamping or permanently removing lamps from the fixture we can save a tremendous amount of energy as compared to the original system. Once again, our four lamp fixture originally consuming 184 watts can now provide slightly less or equal lighting levels, depending on lamp choice, at 46-52 watts per fixture. That is a 50-75% reduction in energy consumption utilizing the original fixtures with only lamp and ballast changes but no improvement in fixture efficiency. The other retrofit option available is a retrofit kit which is available in many configurations but I am going to cover two main types, the recessed troffer retrofit kit and relighting kit. Both kits are more expensive than just re-lamping an existing fixture but offer the added benefit of improved fixture performance, improved light distribution and new fixture components. These can also be installed in the existing fixture from the room side of the ceiling. A retrofit kit reuses the existing fixture housing, lens door frame and lens and consists of a new semi-specular or highly reflective white reflector, lamp holders, electronic ballast and mounting hardware. Specifying a specular reflector will improve the vertical distribution of a fixture and is a better choice for higher ceiling heights while the white reflector has a wider horizontal distribution and is a better choice for low to medium ceiling heights. To retrofit an existing fixture the installer would remove the internal parts of the existing fixture leaving only the exterior housing, lens and lens door frame and its original mounting. Next, the ballast is installed, lamp holders on each end of the fixture, then the new reflector is snapped into place with new lamps and finally, the original lens is closed. On the other hand, a relighting kit reuses only the existing fixture housing and original mounting and includes a new reflector, ballast with mounting tray, lamp holders, lens door frame and lens. The installation is similar to the retrofit kit except the installation of the new lens and lens door frame. Both kits can offer the same energy savings as the de-lamping example above but with improved fixture efficiency that in conjunction with a new layout can reduce the number of fixtures and the energy consumption even more. The relighting kits offer a refreshed look to the interior with new lenses and are also available in LED with dimming options and integrated controls.
Interior lighting covers a very large segment of the lighting retrofit opportunities so I would like to continue with this topic and discuss lamp replacements. Lamp replacements are usually the easiest retrofit to perform and consist of removing existing incandescent, halogen and non-ballasted lamps with screw in CFL lamps, LED lamps and energy savings non-ballasted CFL lamps. Compact Fluorescent lamps (CFLs) come in a variety of sizes, shapes and lamp colors to meet the needs of most incandescent replacements. The easiest way to size a replacement CFL is to divide the existing incandescent lamp wattage by four and find the CFL with the matching wattage. For example, a 100-watt incandescent would require a 25 watt CFL to provide the same lighting levels. There are a few problems that can occur when installing CFL lamps in existing fixtures. First, the physical size of a CFL is different than the incandescent lamp and may not fit due to length or the width of the base of the lamp. Second, if the lamp is on a dimming circuit then a CFL specifically made for dimming must be installed and compatibility with the existing dimmer verified. If the lamp does not dim or dim smoothly then it may be a dimmer compatibility issue. Finally, not all manufacturers rate the lamps the same and so the lumen output must also be compared to specify a replacement lamp that provides the same light level. LED lamps have finally reached a price point and performance level that can make it a viable alternative to CFL lamps for incandescent replacements. Buyers beware, not all LED lamps are created equal and you can no longer compare the wattage of the lamp to find an equal replacement. To clear up some of the confusion with LED lamp selection the U.S. Department of Energy has developed the “LED Lighting Facts Label” that is included on the exterior package of all LED lamps provided by manufacturers that are committed to testing their products to industry standards and publishing the performance results (http://www.lightingfacts.com/). An often overlooked lighting retrofit opportunity is the non-ballasted 4-pin CFL lamp that is typically found in recessed downlights, decorative pendant fixtures and wall sconces and uses a plug-in pin base that is not compatible with screw in lamps. Until recently existing Lamp wattages ranging from 14-42 watts per lamp were the most efficient options available. Manufacturers have now introduced hi-lumen/ reduced wattage replacement lamps that can replace the existing lamps without any modification to the existing fixture, no loss in light output and an energy savings of 4-9 watts per lamp, depending on lamp size. The lamp base is specific to the original lamps wattage therefore, careful consideration must be taken to ensure that it fits.
Successes and Failures
“Just buy a bunch of light bulbs and get someone to install them”, this was my first experience with lighting retrofits. This was also my first experience with the complexity of lighting choices, lighting design and complaints from the end users. Fifty buildings and 100 cases of CFL lamps later, what did I learn? Success is in the details, upfront planning, experience, energy and economic analysis and that there is more to a successful lighting retrofit than installing new lamps in the existing fixtures. At the end of the day, a successful energy retrofit is measured by the occupant’s comfort, the energy saved and the reduction in maintenance costs associated with the new lighting system that you have provided. Regardless of how much energy your lighting design saves, unhappy end users and maintenance personnel can unravel that entire savings as fast as you install it. What have I seen? I have seen the new energy saving CFL lamps yanked back out and incandescent lamps put back in, the new lights that I specified turned off to make way for high wattage halogen task lamps on every desk, often from their own home, and the maintenance department replacing the new hi-lumen fluorescent lamps with whatever was in there hidden stockpile or was a better bargain. So what makes a successful lighting retrofit? They included coordination with the end users, building owners and maintenance personnel and provide the right amount of lighting where it was needed with a mix of economical lighting technologies tailored to each applications needs and often times utilizing the latest modeling software to develop new lighting layouts with retrofit kits or new fixtures. They also included a realistic and conservative approach to energy/ economic analysis in conjunction with specifications and construction documents tailored to the projects existing conditions and specific scope.