Although fluorescent lighting in the home is a relatively new frontier, it has been around for decades in commercial, industrial and retail settings. Although fluorescent lighting has been around for years, there have been vast improvements in technology over the past decade.
Energy cost for lighting cost in a large setting (school, store, industrial setting) can be huge. Annual cost from $20,000-$250,000 are common. Many people have overlooked lighting cost as a potential cost savings. Updating lighting in a facility can result in huge savings and can be implemented with relative ease.
Tubular fluorescent lamps are designated by their diameter (in eights of an inch) and by length in inches. For example an F96T12 lamp is 96 inches long and 12 eights of an inch (1.5 inches in diameter). The most common lamps in use today are the T12 lamps. These are being rapidly replaced or retrofitted with the drastically more efficient T8 and T5 lamps.
Fluorescent fixtures consist of 2 primary components, the ballast and the lamp. A fluorescent lamp works by electrically exciting an inert gas (usually argon) inside the lamp tube. This electrical excitation is the job of the ballast.
Historically light ballast produced the high frequency required to excite the gas magnetically. This was a very inefficient process with the ballast loosing as much as 15-20% of the electricity in heat and magnetic losses. Newer ballast are electronic and can produce the high frequency with little electrical loss. Because the electronic ballast can operate at a much higher frequency and thus excite the lamp at a higher frequency, the same lamp will produce as much as 10% more light just by replacing a magnetic ballast with an electronic type.
More energy efficiency is gained by retrofitting a T-12 lamp with a T-8 lamp or by replacing the entire fixture with a T-5 fixture. For existing applications where a T-12 fixture is in use, a drop-in T-8 lamp is generally available in 4 and 8 foot lengths. This retrofit will require an electronic ballast. Therefore, if the fixture is several years old and has a magnetic ballast this will require a ballast and lamp retrofit. Generally lamp sockets are the same. This retrofit can take place as existing lamps and/or ballast go bad. This reduces the initial cost and makes the facility re-lamping more manageable but also lengthens the time to recover the cost savings over the entire facility.
Retrofitting a T-12 fixture with magnetic ballast to a T-8 fixture with electronic ballast can easily reduce the fixture efficiency by 30% in addition to improving the light output of the fixture as much as 10%.
T-5 fixtures can offer improvements of 20-30% over T-8 fixtures, however a complete fixture replacement or major (and expensive) retrofit is required. T-5 fixtures should be considered for any new construction.