With promises of 20 year lifespans and energy efficiency, LED lighting is a popular lighting technology, especially for hard to reach bulbs. But the LED light output tends to degrade over time, and lighting that is used for many hours of every day may well have a lifespan much shorter than the 20 years that are claimed.
Higher quality bulbs should have better light output over time, and especially for less frequently used bulb locations, a warm, bright light may well be expected over many years of service. However, the light output of LED bulbs should be considered where light is needed.
Since we all have used 100 watt incandescent bulbs, we should first note that the incandescent light bulb produces around 1,500 lumens of light output. A 40 watt, four foot florescent bulb, usually used in pairs, produce around 3,000 lumens of light output, or double the light for roughly half the electrical energy. Thus a twin bulb florescent fixture can produce four times the light as a 100 watt bulb, and the fixture with bulbs is usually less than $20 at the home improvement store for a cheap fixture.
The florescent fixture is very bulky. So when LED bulbs that fit standard screw in sockets are on the shelf, we have to take a good look at the idea. For several years we have been using CFL, or compact florescent lighting bulbs as replacements for standard screw in light bulbs. With a lifespan in excess of five years, they last longer and use less energy, but flicker when turned on and give some people headaches.
A twenty five watt CFL, or compact florescent, the curly lightbulb, does not produce as much light as the 100 watt incandescent bulb, it is about 30 percent less light, but the energy savings are substantial, using one fourth the energy of the old incandescent light bulb, and roughly two to three times the lifespan.
The LED bulb is even more efficient, especially when new. However, LED makers have not yet packed enough light into the standard bulb base yet. Two LED bulbs are usually required to equal the light output of a single 100 watt bulb. At ten dollars ($10.00) per bulb, this is roughly the cost of a florescent fixture, but compact and compatible with a standard screw in base. With 800 lumens of output for just 11 watts, they are five times more efficient than incandescent bulbs and have more than three times the lifespan.
If a light socket requires a 100 watt incandescent bulb to produce the light that is needed, you probably still need to use an incandescent bulb. But if a 50 or 60 watt bulb was sufficient, the new LED bulbs produce enough light to replace the incandescent bulb. Over the lifetime of an LED bulb, it can use 200 kilowatt hours of electricity, or roughly $ 20 on your bill. The same amount of light from incandescent light bulbs would cost $ 100 on your electrical bill and you would have to change the bulb three or four times.
So the economics for LED bulbs exists, but their application is not always practicable.
Running LED lighting on solar power calulations