LED (Light Emitting Diode) lighting is exciting technology and the future of lighting.
LED Lighting uses less power and last up to 20 years compared to typical 2-3 year lives of other bulb types . Their efficiency and long life make LED lighting a great green solution.
The Benefits of LED lighting:
You do not have to change the bulbs/lamps every 1-2 years as you do with other bulb types.
You are making a statement in support of green technology (a great thing!).
Due to the lower wattage, you can use a smaller transformer (save money).
Due to the lower wattage you will have less voltage drop, so you can use thinner cable and have easier layouts (wire in series/daisy chain, instead of understanding voltage drop).
It is improving faster than you can believe. Prices are dropping fast, lumens increasing, color temperatures getting warmer, new technologies enabling higher output with less heat (i.e. longer life/more reliable).
LED technology is improving, but "Buyer beware!". The market is flooded with misconceptions, false claims, and inferior product – all of which can make you very disappointed in LED lighting. You must be careful and use LED for the right application/reasons.
Some quick realities about LED:
Descriptions and specifications may be misleading. Some LED manufacturers have been caught with exaggerated claims and false test data.
Look for data on 4 primary factors:
Color temperature (expressed in degrees Kelvin (K).)
Color Rendering Index (CRI) - indicates how well the light renders colors accurately.
Life span (L70) - indicates when light is meant to dim to 70% of its initial brightness.
There are some other issues to be aware of:
Degradation of color temperature. LED chips actually emit blue or purple light. This is projected through a thin phosphorus coating to produce a light that contain the range of colors that comprise white light. If this phosphorus coating breaks down with heat then the color temperature will begin to shift over time. The light could start out as a nice warm white then degrade to a light that is overly blue.
The lumen (light) output decreases over time. LED's seldom fail completely, instead they grow dimmer over time. When the light loses 30% of its initial level it is considered to have reached the end of its life. For high quality LEDs, the end-of-life (L70) can be up to 60,000 hrs. Lower quality LEDs, or LEDs that overheat, can reach their end-of-light in a far shorter time.
Silicon chips and drivers fail when exposed to too much heat (that is why there is a fan in your computer). The heat produced by the LED and other components must be dissipated outside the LED fixture. If this is not done properly, then early failure is the result.
The concept of solar fixtures - renewable energy, no wires or transformer and easy installation—just stick fixtures in the ground, is optimal, but it does have drawbacks. Most importantly the light is not strong enough to illuminate an area properly. Solar lights will glow like a marker light, noticing that the fixture is on, but will provide very little useable light in a landscape lighting application. Currently, Solar fixtures are best served to be used to identify the edge of a driveway or walkway
As technology improves, solar will become a more useable alternative for professional contractors.