Maximum Yield USA 2016 June | Page 148

ARTIFICIAL LIGHTING “When choosing an LED lighting system, it is important to pay attention to both years and hours listed on light warranties.” Efficiency Efficiency in lighting refers to the ratio of light energy to heat energy produced from a specific energy input. All energy that goes into the light source produces either light energy or heat energy. How efficient a light is depends on the percentage of energy that comes out as light, as well as the percentage that is heat. The primary reason LEDs are so popular is due to their high efficiency. Many LED lights boast 50% less energy use per mol of photons produced compared to traditional HID. LEDs can also deliver light in a specific wavelength. This makes the majority of light produced usable, where other lighting types produce useless wavelengths alongside the useful wavelengths. Production of useless wavelengths consume energy but do not result in photosynthesis. Less efficient lights produce more heat, and high temperatures reduce the efficiency of the light, and its lifespan. Form Factors LED lights come in three main form factors: fixtures, bars and panels. Fixtures are shaped like a box and typically offer high intensity light. Fixtures consume moderate to high amounts of power, take up space, and require higher initial investment. 146 Maximum Yield USA  |  June 2016 Fixtures are shaped like a box and typically offer high intensity light. Fixtures consume moderate to high amounts of power, take up space, and require higher initial investment. Bars come in a number of different lengths and profiles, consume low to medium amounts of power at low to medium intensity, and use space efficiently. Panels (shaped like a slender box) offer low to medium intensity and use low or medium amounts of power. This type of lighting tends to be more expensive than bars but offers better coverage.