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When upgrading fluorescent lighting, don't forget the ballasts

Fluorescent tubes

Ballast technology has improved and shifted in the last 15 years

When we think about overhead fluorescent lighting, we focus on the long fluorescent tubes (lamps) that glow when electrical current moves through them.

But unlike incandescent lighting, where the lamp does all the work, fluorescent light is the product of two components: the lamp and the ballast, a component housed in the lighting fixture (luminaire).

"In a fluorescent system, the ballast plays two roles," says Cristian Suvagau, senior Power Smart engineer with BC Hydro. "It provides starting power to the lamp, and it limits the power to not kill the lamp."

It's tempting to install higher efficiency fluorescent lamps (such as T12s to T8s) without paying attention to the ballasts. But ballast technology has improved and shifted in the past 15 years. If you're not upgrading your ballasts, you won't see the potential energy savings efficient lighting can provide.

Ballasts: what to know

Newer, electronic ballasts operate differently from older electro-magnetic (magnetic) models. They not only save you energy — they out-perform magnetic technology in several ways. Here's what you need to know:

More light, less cost
Electronic ballasts operate at roughly 1,000 times the frequency magnetic ballasts are capable of. 

"If the frequency is higher, more light comes out of the lamp," says Suvagau. "Basically, you enhance the luminous efficiency with a higher frequency." Which means you get the same amount of light for a lot less electricity.

Fine-tuning your lighting system
Electronic ballasts can be manufactured to "underdrive" or "overdrive" the lamps they support, producing more or less light per lamp. This allows you to fine-tune your lighting application to get the level of light you want in different areas of your office or operations.

This is a determination that has to be made at the lighting design stage, before equipment is ordered, however. So Suvagau recommends thinking carefully about your needs and being clear with your contractor about what works, or doesn't, in your current lighting layout, when you're planning a new system.

Note that lighting standards have changed based on modern work patterns and lighting.

Reduced heat
"In any system that transforms energy from one state to another — in this case from electrical energy to light — there are losses," says Suvagau. "Most of the time those losses are in heat. But electronic solid state produces less heat than electromagnetic — much less."

If you're operating cooling equipment, such as food coolers, or air conditioning your space in the summer, that means electronic ballasts help you save on cooling costs, too.

Fewer ballasts
A single electronic ballast can operate up to four lamps, where magnetic ballasts can only support two. Depending on your lighting layout, this may reduce the costs of an upgrade, since you may not have to do a one-for-one replacement of your old ballasts.

Instant start vs. programmed start
"There are two types of electronic ballasts," says Suvagau. "Instant start provide high voltage to the lamp to provide an imperceivable fast start. But it's a shock to the lamp.

"If you have to cycle on and off frequently — for instance, if you have occupancy sensors — the lamp may not handle the shock so well and you can depreciate the life of your lamp by up to 50%."

Programmed start ballasts heat the electrodes first, reducing the shock to the lamp, maximizing both lamp and ballast life. They can cost a bit more, but they'll pay for themselves through reduced wear and tear on the lamps.

Dimming
"Dimming is much easier with electronic ballasts than it was with electromagnetic," says Suvagau. "But continuously dimming is a more expensive proposition for the ballast, so the trend now is to go with pre-set dimming levels, usually that can cut the light to 50%."

That saves energy and is a useful application for areas such as parking garages, hotel corridors or stairwells, where lights are required to be on at all times, but a sensor can restore them to full power when a person enters the space.

No flicker, no buzz
With the higher frequency of electronic ballasts, the flicker some people perceive with fluorescent lights is virtually gone. Ditto the annoying hum, or buzz, sometimes emitted by electromagnetic ballasts.

In workplaces with rotating machinery, the old flickering light could create a stroboscopic effect, a serious safety hazard, making machinery appear to be standing still when it was working. Electronic ballasts, with their higher-frequency operation, eliminate this risk.

Less fading over time
"Whereas a T12 lamp with a magnetic ballast would lose about 30% of its lumen output [ability to produce light] over a median lifetime, it's not more than 5% loss with a T8 or T5 and an electronic ballast," says Suvagau.

That means your lights don't slowly get dim and dingy as the lamps age — they continue to produce steady light until the day they give out completely.

"The key here is that a lamp and a ballast are not individual elements," says Suvagau. "If people say, 'Oh, I'll just change the lamp and not the ballast," they're making a mistake. The two elements have to be handled at the same time to get the best efficiency, and the best lighting effect."

To ensure your lighting retrofit offers you the best gains possible, work with a member of the Power Smart Alliance. Alliance members are independent contractors who are aware of energy efficient options and experienced with BC Hydro incentives.