Fluorescent and LED Troffers: Understanding Options

Most public buildings are equipped with either surface-mounted or in-ceiling rectangular fixtures called troffers that contain 1 or more (usually 4) fluorescent tubes that are most commonly 4 feet long. 

If they are old, they may be T-12 40 watt fluorescents, which are 1-1/2 inches in diameter. In a four-light, four foot T-12 fixture (called 2x4 because of length and width), four lights are typically connected with two magnetic ballasts, which also draw power.

Replacing these involves either replacing the entire troffer or rewiring internally. If the troffers are old or the prisms are yellowed, replacement makes sense. In this case you will buy complete troffers (either T-8 fluorescent or LED, as described below), including internal wiring, sockets, lights, and (for fluorescents) ballasts. You would need only to install the new fixtures and join the electrical wiring to the building’s circuit.

If you wish to retain the current troffers, various retrofits are available. They are described below. The two technology options are a more efficient T-8 fluorescent tube or LED lighting.

T-8 fluorescents

The cheapest retrofit involves T-8 (1-inch diameter) fluorescent tubes. They can be bought in 32W size, but these do not receive rebates. Rebates generally begin with 28W and 25W tubes, which can be found not in box stores but on product websites such as 1000bulbs.com, energyavenue.com, or elightbulbs.com. The old ballasts are replaced with a single electronic ballast, which is smaller and uses no extra power. Since a four-lamp T-12 fixture is 160 watts plus about 19 watts for the ballast, totaling 179 watts, and a 25W T-8 fixture is only 100 watts total, you save in energy costs with this upgrade.

Click here for a downloadable "Energy Savings Calculator" packed with information, and prepared by Vic Myers in South Bend.

Click here for a 1993 article explaining more about T-8 fluorescent lights. As you can see, they have been around for awhile.

LEDs

A more energy efficient option is replacement with complete LED troffers or LED bulbs, which not only last more than twice as long, saving labor, but step down energy use considerably. They also contain no mercury, direct their light downward rather than losing some light into the fixture, and work better with occupancy sensors than many fluorescents do.

Here is an example of a complete replacement recessed troffer. Here is another.

Various LED retrofits are available. Here is a description of the options. Some (“LED instant” or “Plug and Play”) simply plug into the existing lamps with no changes in wiring needed. These are easy to install, but have shorter lifespans and are less efficient than other LEDs. Their compatibility with your fixtures must be tested. A second type requires removal of the ballasts and rewiring, but they are more efficient and long lasting. Installation of these requires more time, care, and expertise, but in the long run the effort pays off. Here are some retrofits: 1000bulbs.com, energyavenue.com, elightbulbs.com, totalbulklighting.com.

A third LED option is an assembled insert that is held to an existing troffer (gutted of old lamps and ballasts) with powerful magnets. As with fixture replacement, minimal wiring is required, but as with other retrofits, the look of the fixtures will remain the same, and the price is lower. Here is an example from Litetronics. The entire fixture is 50 watts, twice as efficient as four 25W T-8 bulbs.