Choosing the Right Ballast
To control noise or flickering, ensure a long life and save as much energy as possible, it is important to choose the best ballast for your fixture. Fluorescent lights work by "exciting" the mercury vapor in the tubes. To do this, it needs a certain level of electrical current to start, followed by a leveling out of the power. A lot of common household fluorescent light bulbs, like those funny spiral-shaped ones you stick in your table lamp, are self-ballasted, meaning the ballast is a part of the light bulb. Many fluorescent light bulbs, however, require an external fluorescent ballast to provide the perfect operating conditions to make it happy.
Instant Start Ballasts
As the name suggests, these start the lamps the moment you flip the switch. Instead of heating up the electrodes, they deliver a high initial voltage that "jump starts" the bulb. Without the need to use extra voltage to heat the electrodes during use, instant start ballasts are an energy-efficient option. Since this method is a little more damaging to the bulb, they are best suited for applications where the lights are left on or off for long periods of time.
Rapid Start Ballasts
These start lamps quickly, though not quite instantly (0.5-1.0 seconds). They supply a starting voltage while also heating the lamp electrodes, which uses more wattage and reduces the life of the bulb. Rapid start ballasts are quickly being replaced by newer, more efficient programmed start ballasts.
Programmed Start Ballasts
Although they take a tiny bit longer to start (1.0-1.5 seconds), programmed start ballasts possess a key feature that make them a better option for applications when lights are switched off and on regularly. With that extra half of a second, the ballast conducts a series of steps that allows it to not only reduce energy consumption but also limit the damage caused by a high initial voltage. The result is a ballast that can be turned on and off frequently without sacrificing cost savings and lamp life. Therefore it is perfect for utility rooms, bathrooms, hallways and rooms that use occupancy sensors.
Emergency Backup Ballasts
If you have ever been in a department store or hotel when the power went out, you probably experienced an emergency fluorescent ballast first hand. Usually installed in offices, schools, hospitals, and other buildings where egress lighting is needed, emergency fluorescent ballasts use a rechargeable battery to provide backup power to fluorescent light bulbs. In the event of a power outage, the lights stay on at reduced illuminating levels for a minimum of 90 minutes for safe evacuation. For an emergency lighting installation, you will need a primary ballast for everyday use and a secondary emergency backup ballast for egress lighting.
Low Temperature Ballasts
Some fluorescent lights need heat to discharge and maintain a steady brightness, so what if your light is in a very cold setting, say the freezer aisle in your grocery store, a cold garage or inside an igloo? For stable and reliable performance in extreme temperature locations you need a low temperature fluorescent ballast. These dynamic cold weather ballasts automatically adjust for cold fluorescent light bulbs to provide optimal light output in below freezing conditions.
How to Replace a Fluorescent Ballast
There are a few reasons you may need to replace your ballast: Converting from a T12 to a T8 bulb, upgrading a dated magnetic ballast, or simply replacing a ballast that has gone bad. Flickering and loud buzzing in fluorescent lights can be the result of a bad ballast. Before you toss out your fixture or bulbs, consider replacing it. Popular brands like Fulham offer a variety of ballasts that power circline fluorescent light bulbs, CFLs and linear fluorescent light bulbs, including T5, T8, and T12 lamps and can replace your current one. There are many tutorials online, like this video, that show how to replace a ballast in a fluorescent light fixture. If you do end up throwing out your lamp, make sure to take proper safety precautions to dispose of your fluorescent bulb.