The operational life of current white LED lamps is 100,000 hours. This is 11 years of continuous operation, or 22 years of 50% operation. The long operational life of an led lamp is a stark contrast to the average life of an incandescent bulb, which is approximately 5000 hours. If the lighting device needs to be embedded into a very inaccessible place, using LEDs would virtually eliminate the need for routine bulb replacement.
There is no comparison between the cost of LED lights vs. traditional incandescent options. With incandescent bulbs, the true cost of the bulb is the cost of replacement bulbs and the labor expense and time needed to replace them. These are significant factors, especially where there are a large number of installed bulbs. For office buildings and skyscrapers, maintenance costs to replace bulbs can be enormous. These issues can all be virtually eliminated with the LED option.
The key strength of LED lighting is reduced power consumption. When designed properly, an LED circuit will approach 80% efficiency, which means 80% of the electrical energy is converted to light energy. The remaining 20% is lost as heat energy. Compare that with incandescent bulbs which operate at about 20% efficiency (80% of the electrical energy is lost as heat). In real money terms, if a 100 Watt incandescent bulb is used for 1 year, with an electrical cost of 10 cents/kilowatt hour, $88 will be spent on electricity costs. Of the $88 expense, $70 will have been used to heat the room, not light the room. If an 80% efficient LED system had been used, the electricity cost would be $23 per year - there would be a cost savings of $65 on electricity during the year. Realistically the cost savings would be higher as most incandescent light bulbs blow out within a year and require replacements whereas LED light bulbs can be used easily for a decade without burning out.
Our white LED lights currently come in packages which contain 36 or 48 LED lamps and can be adapted for use with any power supply or casing. Our clusters allow for conversion to operate from all common caving batteries, e.g. FX5/Kirby pack down to two AA cells, in case portability is needed. We have produced a seven-LED cluster light source as an alternative to low wattage light bulbs and a possible portable light source.
The main limitation to the adoption of white LED lighting as a lighting standard is the current high cost of led bulbs. Although the cost keeps going down, LED light bulbs are still expensive. A single AC bulb (17 LED), replacing a 25 watt incandescent, will cost about $40. Although LED's are expensive, the cost is recouped over time and in energy cost savings. Factor in that it is significantly cheaper to maintain led lights, the best value comes from commercial use where maintenance and replacement costs are expensive. Traffic lights and outdoor signs, for example, are being switched over to LED's in many cities. Smaller arrays, such as those in flashlights, headlamps and small task lights are great for specialty and outdoor use. LED based automotive headlights are current being used in high end luxury cars.
It will be interesting to see what developments are coming for more residential applications of LED lights. LED lighting technology has been researched and developed for the past two decades and we are beginning to see practical applications from this work. There is already wide spread use of LED traffic signs and LED headlights where a premium is placed on a reliable light source that is cheaper and less labor intensive to maintain. We in the industry are certain that tomorrows LED lights will last longer and consume even less power than todays energy efficient led light bulbs. LED lighting will be used to replace virtually every type of light, bulb, and lamp that is currently in use.
