Incandescent lamps operate without a ballast. In an incandescent, electric current runs through a wire filament and heats the filament until it starts to glow. These lamps light up instantly, providing a warm light and excellent color rendering. However, incandescent lamps have a low efficacy compared to other lighting options and a short average operating life.
Incandescent lamps are the least expensive to buy, but because of their inefficiency and short life spans, they usually are more expensive to operate.
Beginning January 1, 2012, the most common incandescent bulbs we use are required to be about 25% more energy efficient to meet the new standards set forth by the Energy Independence and Security Act of (EISA) 2007. The more traditional inefficient 100 watt bulbs will give way to choices that use a maximum of 72 watts to provide you a comparable amount of light (lumens). Traditional, inefficient 100 watt incandescent light bulbs will not meet the standards and will no longer be available at most stores. The EISA 2007 act specifically limits the import or manufacture of inefficient bulbs. Stores will be able to sell remaining inventory.
Compact Fluorescent Lamps or CFLs:
CFLs produce light differently than incandescent bulbs. In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits light.
CFLs need a little more energy when they are first turned on, but once the electricity starts moving, use about 75 percent less energy than incandescent bulbs. The ballast helps "kick start" the CFL and then regulates the current once the electricity starts flowing. This entire process typically takes 30 seconds to 3 minutes to complete, which is why CFLs take longer than other lights to become fully lit. CFLs with decorative covers like globe or reflector shapes have a unique design challenge that results in the tradeoff of a slower warm up time, which is why these CFLs take longer than bare spirals to reach full brightness.
Older CFLs used large and heavy magnetic ballasts that caused a buzzing noise in some bulbs but most CFLs today - and all ENERGY STAR qualified CFLs - use electronic ballasts, which do not buzz or hum. CFL bulbs have also evolved to include a range of light colors, including warm (white to yellow) tones. Some are encased in a cover to further diffuse the light and provide a similar shape to the older incandescent bulbs.
The light produced by a fluorescent tube is caused by a very small amount of mercury mixing with inert gases to conduct the electrical current. This allows the phosphor coating on the glass tube to emit light. Fluorescent lamps require a ballast to regulate operating current and provide a high start-up voltage. Electronic ballasts outperform standard and improved electromagnetic ballasts by operating at a very high frequency that eliminates flicker and noise. Electronic ballasts also are more energy-efficient. Improvements in technology have resulted in fluorescent lamps with color temperature and color rendering that is comparable to incandescent lamps.
The traditional tube-type fluorescent lamps are usually identified as T12, T8 or T5 (the T stands for tubular and the 12, the 8 and the 5 represent the number of 8ths of an inch in diameter.) The most common T12 lamps are 34 and 40-watt, 4-foot lamps, and 60 and 75-watt, 8-foot lamps.
As part of the mandates from the Energy Independence and Security Act of 2007, the T12 magnetic ballast is no longer being produced as of July 2010 so many have already changed these out to the newer, more efficient electronic ballast. In addition, starting in July 2012, manufacturers will be required to stop producing many of the 4-foot and 8-foot T12 lamps. Because the lamps will quickly not be available for purchase, all facilities containing these types of lights will be forced to make a change to their existing lighting systems in order to accommodate a more energy-efficient alternative.
High-Intensity Discharge Lamps:
In a high-intensity discharge lamp, electricity arcs between two electrodes, creating an intensely bright light. Mercury, sodium, or metal halide gases act as the conductor. HID lamps use an electric arc to produce intense light. Due to the intense light they produce and their high efficacy, HID lamps are commonly used for outdoor lighting and in large indoor arenas. Like fluorescent lamps, they require ballasts. HID lamps take up to ten minutes to produce light when first turned on, because the ballast needs time to establish the electric arc. Since the lamps take some time to establish, they are most suitable for applications where they stay on for hours at a time. They are not suitable for use with motion detectors.
The three most common types of HID lamps are mercury vapor, metal halide and high-pressure sodium. Mercury vapor is the oldest of these technologies and is essentially obsolete. It has very limited application due to its poor efficacy and color rendering. High pressure sodium is most common in exterior applications due to its lamp life and efficacy. However, it still has poor color and color rendering. Metal halide is the most commonly used HID technology because it has better (whiter) color and color rendering. It also has better efficacy than mercury vapor.
Low-Pressure Sodium Lamps:
Low-pressure sodium lamps provide more energy-efficient outdoor lighting compared to high-intensity discharge lighting, but they have very poor color and color rendering. Typical applications include highway and security lighting, where color isn't important. Like high-intensity discharge lighting, low-pressure sodium lamps require up to ten minutes to produce light and have to cool before they can restart. Therefore, they are most suitable for applications where they stay on for hours at a time. They are not suitable for use with motion detectors.
The light-emitting diode (LED) is one of today's most energy-efficient and rapidly-developing lighting technologies. LEDs last longer, are more durable, and offer better light quality than most types of lighting available. LED lighting is very different from other lighting sources such as incandescent lamps and CFLs. Key differences include the following:
Light source - LEDs are near-monochromatic light sources. They emit various colors (except white) depending on the materials from which they are made.
Direction - LEDs are directional-much like a flashlight-which makes them ideal for applications such as recessed downlights and task lighting. With other types of lighting, the light must be reflected to the desired direction and more than half of the light may never leave the fixture.
- LEDs emit almost no heat. In comparison, incandescent lamps release 90% of their energy as heat and CFLs release about 80% of their energy as heat.