Basic LED Performance Characteristics
LEDs can use up to 90% less energy than incandescent lamps, 50% less than HID systems, and 25% less than older fluorescent systems. These figures are highly generalized, but as LEDs continue to advance in lumen per watt output, these figures will likely become more effective and uniform. It should also be noted that since LEDs are highly directional in nature, less light energy is lost to diffusion and more applied to the target area, effectively allowing an LED of far less wattage and output to perform the same function as incandescent and HID systems of much higher power.
LEDs are highly recyclable and contain negligible amounts of materials that could be considered hazardous in some way. This means no special or expensive disposal requirements and less impact on the environment.
LEDs are the longest lived lighting technology. LEDs are now available capable of operating for 50,000 to 100,000 hours. This long life reduces maintenance costs and lengthens the time between servicing and replacements.
LEDs are an instant on lighting technology. Some lighting types such as fluorescent and HID require warmup periods before they reach full output. LEDs reach full output in less than one second.
LEDs run cooler than all other lighting types. The cooler operation of LEDs helps to lower costs associated with maintaining temperatures at a comfortable level, and greatly reduces the chance of accidental burns and even ignition of flammable materials should the lamp come into contact with skin or flammables.
Basic HID Performance Figures
HID lamps are far more efficient than incandescent or fluorescent lamps. They can produce in excess of 90 lumens per watt, making them more efficient than incandescent lamps and most types of fluorescent fixtures.
HID lamps have some of the highest output capabilities of all lamp types. For this reason they are currently the lighting of choice for large scale illumination applications such as stadium and outdoor industrial operations. LEDs are rapidly reaching this level of output, so this standing is likely to change in the near future.
HID bulbs contain toxic materials in their construction including mercury and small amounts of slightly radioactive materials. For this reason they are classed as hazardous materials and require specialized disposal and recycling handling when they reach the end of their service life.
HID lamps have a very long operational life, with metal halide versions reaching up to 50,000 hours of runtime. However, HID lamps tend to lose efficiency and color quality over time, with lumen output decreasing and significant color shifts occurring well before the lamp reaches the end of its life. HID lamps are also prone to a phenomena known as “cycling” wherein the lamp shuts down and restarts frequently as it nears the end of its operating life.
HID lighting requires a warmup period in order to reach its full output. Most common HID systems require anywhere from 1 to several minutes of warmup time before they reach full output. Additionally, HID lamps cannot be cycled on and off quickly, requiring a cool down period of several minutes between shutdown and restart. Newer HID systems with pulse start ballasts have reduced this lag between startup and full output, but it is not eliminated.
HID lamps produce significant amounts of heat and as a result need ample space around the fixture for effective heat dissipation. They should not be operated near flammable materials and pose a serious risk of burns or injury if they come into contact with human skin while in operation.
HID lamps cost less to maintain than fluorescent or incandescent systems due to their longer operational life and higher efficiency. However, HID lamps contain ballasts that are necessary for operation, increasing the potential costs of replacement and servicing.