Everyone's familiar with the fixtures shown at right. Fluorescent light fixtures are a ubiquitous part of life.
A quick lesson in fluorescent tube lighting
Fluorescent lamps require a ballast to operate properly. The ballast's first job is to provide a quick burst of voltage to get the lamp going. From there, it regulates the current. Without it, the lamp would draw an ever-increasing amount of current, and very quickly it would overheat and burn out. The ballast is external to the bulb; it is, instead, part of the fixture, and when a ballast starts to go bad, you get flickering and other erratic behavior, at which point the ballast needs to be replaced. In other words, it's one more failure point in the system, and to replace a failing ballast, you need to turn off power to the fixture and perform electrical work—it's not as easy a fix as simply replacing the bulb.
LED tubes, on the other hand, come with built-in drivers to regulate the current, and, therefore, don't require ballasts. If you convert a fluorescent fixture to LED—a fairly simple job—removing the ballast will be the last electrical work you ever need to do to that fixture.
So, what is an LED-ready fixture?
This is simply a tube light fixture that has no ballast. It looks just like a fluorescent fixture, but it accepts LED tubes, allowing you to enjoy the energy and maintenance savings without having to bypass a ballast or purchase special ballast-compatible LED tubes.
When would you buy an LED-ready fixture?
The biggest reason, of course, would be when you need to install brand new light fixtures. LED-ready fixtures allow you to take advantage of the energy efficiency and long working life of LED tubes without having to make any modifications to your new fixtures. Your lighting installation will be green from the get-go.
You also may consider LED-ready fixtures when you want to upgrade your existing fixtures to LED. The fluorescent fixtures you have in place would need to have their ballasts removed to make them LED-ready, so you're looking at a wiring job either way. And if your existing fixtures are showing their age, replacing them with LED-ready fixtures gives your installation a fresh, clean look. ELEDLights.com offers LED-ready fixtures in 4ft and 8ft lengths as well as fluorescent troffer upgrade kits, for those who want to upgrade their fixtures instead of replacing them.