Fluorescent bulbs come in two primary types, T8 and T12 types. Each type has its own set of advantages and disadvantages. Overall, fluorescent bulbs are known for their ability to provide bright and steady light over a larger surface area than a traditional bulb. The bulbs also tend to offer consistent lighting in a room, bathing the room in light.
Size
One primary difference between T8 and T12 fluorescent bulbs is the size of the bulbs and their bases. While both bulbs come in standard lengths, commonly four feet, the number 8 or 12 refers to the difference in the diameter of the bulb. T8 bulbs are eight eighths of one inch, or one inch in diameter, while T12 bulbs are twelve eighths and have a larger diameter of one and a half inches.
Energy Usage
Another area in which these two bulbs differ is in their energy usage. A T8 bulb is 32 watts, while a T12 bulb is 40 watts. This makes the T8 bulb a more energy efficient bulb to use. A government standard known as the Federal Minimum Energy Standard requires buildings to start using energy efficient lighting, favoring the T8 over the T12.
Light Output
Both bulbs put out similar light output although the T8 puts out slightly more light, although the difference is not noticeable to the human eye. According to Philips, a maker of light bulbs and lighting equipment, a T8 bulb produce around 2600 lumens (the unit used to measure light output) while the T12 bulb puts out around 2520 lumens.
Over time the bulbs begin to lose their intensity and brightness. T8 bulbs have a slower period of decrease, losing only 10 percent of their initial brightness after 7,000 hours of use. In comparison T12 bulbs can lose 20 percent or double the T8 lose after the same number of hours.
.
