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Not sure about CFLs? Get the right light for your business

They're the poster child of energy-efficient lighting – the curly bulb that was, for most of us, our first departure from the old Edison incandescent bulb.

Trouble is, your first experience with compact fluorescent lamps (CFLs) may not have been all sweetness and... er... light.

"Absolutely, the technology is not a stable thing," says Nikolay Smirnov, a senior engineer with BC Hydro, commenting on the quality of early CFLs. "CFLs are constantly improving; they're already better than they were even a year ago."

Which means if you didn't like the way CFLs looked a few years ago, it's time to try again. CFLs are still the most cost-effective option for traditional screw-in fixtures. And since B.C. government regulations now prohibit the sale of 75W to 100W incandescent lamps, it's time to get more savvy about making CFLs work for your business – whether it's an office, restaurant, or retail space.

Get to know about colour temperature

The first thing to know is that CFLs offer more choice, in terms of the appearance of light they produce, than incandescents.

You may have noticed that lamps (bulbs) may be labeled "cool," "warm," or "natural" – attempts to describe the light they give. Less confusing, especially if you purchase from a lighting wholesaler, is to cut to the science underneath the marketing terms.

Colour temperature is a characteristic of light measured in degrees Kelvin. The incandescent lamps we grew up with provided light with a colour temperature of about 2,700 K – considered the "warm" end of the scale. A candle flame is about 1850 K, while vertical sunlight is up around 6,000 K. We perceive the warmer light as more yellow, and the cooler (higher temperature) light as more blue.

Another measure of the quality of light cast by a lamp is its CRI, or colour rendering index, expressed on a 1-100 scale. Simply put, the higher the number, the more faithfully the light source will reproduce colours as compared to natural light (sunlight).

"Early CFLs had a CRI of about 60%," says Smirnov. "By comparison, modern lamps (even the cheapest ones) have a CRI of over 80%, which is acceptable for the majority of lighting applications."

Choose the right temperature for your setting

Our bodies are wired to react to different light in different ways. This is where experimenting with different CFLs for your setting can make all the difference.

"Bluer light [higher colour temperature] increases alertness," says Smirnov. "It's human nature to feel more alert with light in the higher, bluer range, while warmer light, which can make you feel more sleepy, is not a good choice for an office."

However, a warmer colour temperature may be more appropriate for a lobby or a setting where you want people to relax. We also have cultural reactions to light. In hot countries, bluer light – perceived as cooler – is preferred. In countries with cold climates, we gravitate to the cozy end of the spectrum we associate with warmth (think firelight).

Smirnov recommends CFLs with a colour temperature of 3,500 – 4,100 K for an office environment. (You can get lamps with higher temperatures, but they can seem too intense in some settings.)

You may also notice that some colour temperatures work better with your displays or decor – it's worth trying a few different options. Home builders have found, for example, that a display suite doesn't show as smartly if the colour temperature of the lamps is too "yellow" – a colour temperature of 3,000 – 3,500 K is needed to make the suites look "crisp."

Note that your choice of colour temperature may change depending on the application. "Green vegetables look better under cooler [higher temperature] lights," says Smirnov. "But red meat will appear spoiled, and red tomatoes will not be appealing, under a cool temperature light."

Other considerations: size, shape, dimmability

CFLs now come in a wide variety of sizes and shapes [PDF, 522 Kb], and are able to fit in most traditional screw-in fixtures. There are dimmable and tri-light lamps, though these tend to cost more.

Because they are so efficient (using approximately 75% less energy than a standard incandescent lamp to produce the same amount of light) they waste less energy putting out unwanted heat. If your space uses air conditioning to cool occupants, CFLs save money twice. They also cause less damage to merchandise, since they produce little heat and little of the ultraviolet (UV) light that can cause items to fade over time.

However, CFLs don't sparkle. "Incandescents have a sparkle about them," says Smirnov. "CFLs, with their phosphor coating, don't provide that element of sparkle."

For this reason, in specific display settings such as retail, halogens or LEDs may be preferred. For general lighting, however, fluorescent light sources are the most cost-effective option.

Finding the right CFL for the various spaces in your business may take some trial and error – a lighting contractor knowledgeable about efficient options may be able to help. But the payoff in saved energy is worth it. And given that they last up to 10 times as long as incandescents, once you find the shape and colour temperature you like, you likely won't have to replace them for a few years.