LED lights can be more efficient, durable
Light–emitting diodes (LEDs) produce visible light very efficiently when an electrical current passes through semiconductor material inside them.
LED lighting differs from incandescent and compact fluorescent lighting (CFL) in several ways, and it can be more efficient, durable, versatile and longer lasting.
LEDs are directional light sources, which means they emit light in a specific direction, unlike incandescent and compact fluorescent bulbs, which emit light and heat in all directions. For this reason, LED lighting is able to use light and energy more efficiently in many applications. However, it also means that sophisticated engineering is needed to produce an LED light bulb that shines light all around like an incandescent A-shape bulb.
Incandescent bulbs produce light using electricity to heat a metal filament until it becomes white hot or is said to incandesce. As a result, incandescent bulbs release 90 percent of their energy as heat.
In a CFL, an electric current flows between electrodes at each end of a tube containing gases. This reaction produces ultraviolet (UV) light and heat. The UV light is transformed into visible light when it strikes a phosphor coating on the inside of the bulb.
Because LED lighting systems don’t radiate heat, the heat produced from the power going into the product must be drawn away from the LEDs. This is usually done with a heat sink – a passive device that absorbs heat and dissipates it into the surrounding environment.
Common LED colors include amber, red, green and blue. There is actually no such thing as a white LED. To get white light, color LEDs are mixed or covered with a phosphor material that converts the color of the light. Colored LEDs are widely used as signal lights and indicator lights, like the power button on a computer.
LEDs are also incorporated into bulbs and fixtures for general lighting applications. Because they are small, they provide unique design opportunities.
The right light bulbs can save you money
Nearly 11 percent of your home’s electricity bill is attributed to lighting. Changing your old incandescent bulbs to new ENERGY STAR®-certified light-emitting diodes (LED) is a simple step you can take to make your home more energy efficient.
If every household in the United States replaced its five most frequently used incandescent bulbs with ENERGY STAR-certified bulbs, we would save about $8 billion in annual electricity costs.
ENERGY STAR-certified lighting saves you money because it meets strict performance requirements that are third-party-certified to provide the following benefits:
- Less Energy: ENERGY STAR-certified bulbs use about 75 percent less energy than your old incandescent bulbs while producing the same amount of light. Each ENERGY STAR-certified bulb will save about $6 per year in electricity costs, or more than $40 over the lifetime of the bulb, which pays for itself in about six months. For the greatest savings, install ENERGY STAR-certified bulbs in the fixtures that you leave on the longest.
- Less Heat: ENERGY STAR-certified bulbs produce about 75 percent less heat than incandescent bulbs, which makes them safer to operate and reduces the amount of energy needed to cool your home in the summer.
- Long Life: ENERGY STAR-certified bulbs last six to 25 times longer than incandescent light bulbs and are backed by manufacturer warranties. Since these bulbs need to be replaced less often, they’re also convenient for those hard-to-reach fixtures.
Choosing the right replacement bulb
The light from a bulb is described in two ways …
- Brightness: The amount of light produced by a light bulb is measured in lumens, not watts. The more lumens, the brighter the bulb. However, since most consumers are familiar with the amount of light produced by incandescent bulbs, most light bulb manufacturers conveniently indicate on the packaging the equivalent incandescent wattage as a point of reference.
- Color Shade: The color of light produced by a light bulb is measured in Kelvins (K). A higher number means that the light is whiter (3000K) or bluer (4100K). A lower number means that the light is more yellow (2700K). Most ENERGY STAR bulbs produce light that matches the color of incandescent bulbs in the range of 2,700K to 3,000K, but other varieties are available.