Fluorescent Tubes

Chances are, you’ve experienced the glow of a fluorescent lamp at least once during your lifetime. These are typically found in kitchens, garages, workplaces and businesses and tend to be more efficient than incandescent styles, lasting up to 20 times longer. They also provide ample lighting for large spaces and give off less heat than incandescent models. If you’re searching for fluorescent tubes for your lighting fixtures, be sure to note the size and wattage you need before making your purchase.

How do fluorescent tubes work?

Your fluorescent lamp emits light by running an electrical current to the electrodes located at each end. This causes electrons to travel through the inert argon gas inside from one end of the tube to the other and back. While traveling, the electrons may collide with the small amount of mercury also inside, which causes the atoms to become excited and increases the energy levels of the electrons. Once the electrons return to their original energy level, they release light photons.

What size does my tube light need to be?

It’s important to note the size of the tube light you’re replacing to ensure you pick up a matching bulb. Though they may all seem similar, they can come in a number of different sizes. You can determine the size of an existing bulb by looking at its designation, which may resemble the following format: “F30T12/CW/RS.” Some variations may occur, but typically the format can be deciphered into the following meanings:
• F: Fluorescent; “FC” denotes a circular shape, while “FB” or “FU” denotes an U shape.
• 30: Rated nominal wattage.
• T: Shape, as in “T” for “tube.”
• 12: Diameter in eighths of an inch, or 12/8 inches (or 1 ½ inches) in diameter.
• CW: Temperature color; in this case meaning “cool white.”
• RS: Mode of starting; in this case a rapid-start lamp. A high-output rapid-start lamp will be designated “HO,” a very high-output will typically be designated “VHO,” and a preheat or an instant-start lamp will not have a designation.

• T2 / ¼ inch: The T2 size is extremely slim. The fitting at each end of the tube lacks the protruding pins that are typically found on larger sizes.
• T4 / ½ in.: These are typically used in slim lamps.
• T5 / ⅝ in.: Newer, more efficient versions of this size introduced in the 1990s have replaced the original styles from the 1950s and earlier years.
• T8 / 1 in.: These have become more common since the 1980s and may be referred to as the standard size.
• T9 / 1⅛ in.: Designated for circular fluorescent tubes.
• T12 / 1½ in.: This size is no longer being produced due to upgraded federal energy-efficiency standards. If you have a fixture that uses a T12 bulb, you may try using the newer T8 size; however, it’s more than likely the new T8 bulb will simply burn out after three or four uses. Instead, it’s recommended that your old fixture be upgraded to accommodate the new, more efficient bulbs on the market today. This may seem like a headache but could result in lower energy costs over the long run, since newer fluorescent lamp models are up to 40 percent more efficient.

What does temperature have to do with my fluorescent lights?

The temperature of your lights refers to the range of color attributed to the light they emit. This varies from a warm white to a cool, daylight-like white. The temperatures are measured in degrees Kelvin (°K), and you can see which ones result in what lighting effects here:
• 6,500 °K – Cool daylight: This is typically used only in special daylight lamps, as it’s extremely white.
• 6,000 °K – Daylight: If you want your fluorescent light bulbs to simulate natural daylight, this is the temperature to choose.
• 4,000 °K – Cool white: You might associate this color with a hospital or clinic.
• 3,500 °K – White: This is the standard temperature and color.
• 3,000 °K – Warm white: Similar to the color output of a halogen lamp, though it seems to be whiter than an incandescent lamp.
• 2,700 °K – Very warm white: If you want a cozier ambience, the light of this temperature closely resembles the warm, white glow emitted by an incandescent bulb.