Light output is measured in "lumens." A T8, 32-watt fluorescent bulb is engineered to emit up to a generous 95 lumens for each watt of power taken in, according to Other Power. T8 bulbs lose only six percent of their lumen output during the first 40 percent of their rated lives, according to Facilities Net. T8 fluorescent bulbs are some of the longest-lasting bulbs on the lighting market. They are rated to last from 20,000 to 30,000 hours, according to Buildings. Buildings claims T8 bulbs have an excellent color rendering of between 70 and 95 (100 is the highest possible rating).
All types of fluorescent lights are capable of providing the same illumination as incandescent bulbs while using up to 35 percent less energy, according to Buildings. Earth Energy claims that fluorescent bulbs are capable of lasting for around ten times longer than incandescent bulbs. T8 bulbs are manufactured to be smaller in diameter than T12 bulbs, increasing their practical applications. Fluorescent lights, including T8 lights, operate at much cooler temperatures than other light bulbs. For example, a T8 light's peak lumen output occurs at around 95 degrees, while an incandescent bulb burns at several thousand degrees Fahrenheit. According to U.S. Naval Observatory Flagstaff Station, regularly operating a T8 fluorescent bulb for a year can cost the consumer between $6 and $35, depending on the wattage of the bulb. Operating a T12 bulb can cost between $8 and $44 per year, while an incandescent can cost up to $80 per year and a high-pressure sodium bulb can cost upwards of $172 per year.
Consumers have access to high-output T8 bulbs, which are even more efficient than standard T8 bulbs. These "Super T8" bulbs are 20 percent more efficient than the standard T8 bulbs and last up to 4,000 hours longer, according to Buildings. In the 1980's, 4-foot T8 bulbs contained around 40 mg of elemental mercury. Since then, advances in T8 bulb technology have been made to reduce the mercury content down to around 12 mg per tube.