What Is In Fluorescent Light Bulbs?
A fluorescent lamp contains mercury vapor, electrodes, and a white coating on the inside of the glass envelope. Electricity is passed through the electrodes at each end of the fluorescent bulb. This excites the mercury vapor which then gives off an ultraviolet light. Finally, this UV light is then converted into visible light by the white coating inside this energy saving light bulb. Other important items to note is that all fluorescent lightbulbs require a ballast to operate and they are relatively cool to operate since they do not produce as much heat as other light sources.
Fluorescent light bulbs are also one of the most efficient light sources available. In addition, depending on the fluorescent lamp and the conditions which it is being operated, the rated life can be somewhere between 8,000 and 100,000 hours. The "rated life" of fluorescent light bulbs signifies the time at which 50% of a large quantity of these lamps will have burned out. This means that 50% of fluorescent lightbulbs will burn out before the "rated life" and 50% will burn out after the "rated life." The "rated life" does not mean that every fluorescent lamp will last at least that long. So, fluorescent bulbs can save you money by being both an energy efficient light bulb and lasting much longer than comparable incandescent light sources.
Color Temperature and Color Rendering
Fluorescent lamps are now made in a variety of color temperatures: e.g., warm white, natural white, cool white, and daylight. Fluorescent lighting was invented in 1926 and has come a long way since those days. The kind of fluorescent light bulbs used in offices for a long time was only cool white (slightly bluish) and, unfortunately, the relatively poor version is the only kind of fluorescent lighting that many people still know.
In addition to a variety of color temperatures, fluorescent light bulbs come in a variety of color rendering indices (CRI). It is now possible to buy lamps with a good color rendition in the 70s, a very good color rendition in the 80s, and an excellent color rendition in the 90s. The "old" fluorescent bulbs used in offices for many years had a CRI of about 60, a relatively poor color rendering index.
For the home we recommend using a warm white fluorescent lightbulb with a color temperature of around 3000K and a CRI greater than 80. This type of fluorescent lamp will provide a very good color rendition and the kind of "warm" light that most people like in their homes.
Fluorescent Lamp Types
There are a number of different fluorescent lamp sizes and types on the market today ranging from long linear, or tube, to small compact fluorescent and sizes in between. Below are some different fluorescent light bulb types available:
- Linear - these fluorescent tubes include T2, T4, T5, T8, and T12 sizes. The number indicates the diameter in 1/8 inches. For example, a T8 fluorescent light bulb is 8 inches, or one inch, in diameter. The length is determined by the fluorescent lamp's wattage.
- Circline T9 - as the name suggests these fluorescent bulbs are circular in shape and 9/8 inches in diameter.
- Compact Fluorescent - used most often when replacing incandescent lamps in many common light fixtures. CFLs are also available in different sizes and shapes.
Many people like to dim their lights. In order to have a dimmable fluorescent light bulb you need a special dimmable fluorescent ballast that is in turn controlled by a special fluorescent dimmer. However, while dimming other forms of light sources, such as incandescent, increases a lamp's average life, more often than not, dimming a fluorescent light bulb will actually reduce its average life. If you are interested in dimmable fluorescent, along with some other benefits, look at cold cathode fluorescent lamps. CCFLs can be dimmed and they include other benefits. They are also wet-rated for outdoor use and turn on instantly to full light output.
Fluorescent Lamp Disposal
Since fluorescent light bulbs contain mercury you cannot just simply throw them away in the trash when they burn out or break. The biggest reason for this is that waste management workers can unknowingly handle trash with broken fluorescent lightbulbs and become exposed to dangerous levels of mercury. Therefore, please recycle fluorescent bulbs.
Where to Recycle Fluorescent Bulbs?
Bring your old fluorescent lamps to an EPA-approved fluorescent lamp recycling location. Some big box improvement stores, such as Lowe's and Home Depot, have places for you to drop off your fluorescent light bulbs. In addition, here are number of websites that we found that can either help you dispose of your burned out fluorescents or tell you where you can recycle them.