Efficient Lighting: Are T5 lamps the answer? by Samantha Russem LC, LEED AP, Nexamp Lighting Project Manager

Green…Energy Efficiency…Conservation…Big Savings! With so many energy buzz words being thrown around, many people feel like they must participate in the green boom or they’ll be left behind. In the residential market, self-ballasted compact fluorescents and LEDs are keeping consumers busy as they try to determine how they can save energy while making a difference in the world. In the commercial and industrial market, end users are focused on the bottom line. Even with this difference in perspective, the same question looms over both sides: Can being more energy efficient really save money? The answer is unequivocally, “yes”, but how do we get there? Misinformation about lamps and their use, is leading to inappropriate retrofits, insufficient lighting and waste. Educating new energy designers on how to effectively use lamps to maximize light output while minimizing energy output, will go a long way towards improving both the environmental and economic impact that lighting technology can have. A perfect example of how important this educational process is, can be found in the story of T5 Fluorescent lamps. T5 lamps were introduced to the US market in 1996 with little fanfare. Although these lamps were 3/8” smaller in diameter then the standard T8 lamp, the light output was similar to that of the T8 and they were more expensive, so many designers weren’t able to find appropriate applications for these lamps. In 1998, the T5HO lamp was introduced, providing a much greater impact on the market because of their explosive lumen package. These 5,000 lumen lamps significantly improved upon the standard 3,200 lumen T8 lamps. Even more impressive was their competitive edge over the older HID lamps that were still flooding the warehouse, industrial and big-box retail markets. A common and quick retrofit is a one for one replacement of a standard 400 watt MH fixture with a 6 lamp T5HO fixture, based upon maintained lumens. This quick fixture change could save the end user over 100 watts per fixture. This type of energy savings can quickly add up to huge financial savings. On the surface, this sounds like a great idea. Unfortunately, it’s not always this simple. Besides being energy efficient, HID lamps have been very successful because of their versatility to ambient temperature. No matter how hot or cold, HID fixtures will thrive. Although it seems the industry is aware that fluorescents become much more inefficient when at lower temperatures, many would be surprised by what lamp manufacturers are considering a “low” temperature. Standard T8 lamps are most efficient at 77°F (25°C), also known as standard room temperature. Although most warehouses won’t be heated to this temperature, they may come relatively close. T5 lamps, on the other hand, are most efficient at 95°F (35°C). Rarely are these T5HO retrofits in places where a maintained temperature is close to this 95°F threshold year-round. Of course, once the fixture has been turned on, what is most important is the temperature inside the fixture itself. Since many T5 lamps are used in relatively small, compact fixtures, the heat inside the fixture can actually approach the 95°F that is needed for peak efficiency. Issues arise when open air T5HO low / high bays are replacing these HID fixtures, because they aren’t able to retain the heat of the lamps and thus actually provide the light output they are being designed to provide. Designers are often aware of this issue and design their layouts accordingly. Unfortunately, when systems are designed by under qualified people or when designers are influenced by overzealous sales people, the true aesthetic, economic and environmental benefits of new lighting technologies are not achieved. If a retrofit is designed without taking into consideration ambient and fixture temperatures, the space will likely be under lit if utilizing T5 lamps. It’s true that the energy saving story will still be there, and the end user will still be able to see a savings in energy consumption, but at what cost? If these commercial and industrial spaces are under-lit, then productivity may diminish, or accidents may increase, not to mention sales may decrease, if warehouse outlets don’t maintain the bright, upbeat environment that keeps people excited and moving quickly through the aisles. It is important to understand that clean energy design is about more than just saving dollars. It is about utilizing new and improved technology in the proper way to maintain or improve light output with substantially less energy. The tradeoffs between T5 and T8 technology illustrate this point well. When deciding between these two technologies, a designer must take into account environmental factors, such as temperature, before selecting the proper solution. While T5 lamps have the potential for fantastic energy savings, that savings will only be achieved under the proper temperature conditions. Ignoring such factors can ultimately short-change the end-user and the environment, while not achieving the desired economic benefits. Nexamp is a full service clean energy solutions company. Nexamp analyzes, designs, finances, builds and maintains clean energy projects that reduce energy costs and carbon emissions for businesses, governments, and homeowners. Our solutions include renewable energy, energy efficiency, and energy management. Nexamp combines energy project construction experience with expertise in energy technology, markets, finance, and policy to make clean energy simple and profitable for our clients.