Compact Fluorescent Light Bulbs (CFL)
All about compact fluorescent lighting
As you make the decision to get Power Smart, your first step in saving energy is often switching out electricity-hogging incandescent bulbs for compact fluorescent bulbs. Choosing the right light, however, can be a daunting task for the unenlightened.
Before you head to the hardware or lighting store, take the time to educate yourself about compact fluorescents, in particular the basics of colour temperature, shape and lumens (light output). Keep in mind that not all stores have a wide selection of CFLs, and that a phone call in advance of your trip may save you some time.
You may also want to print out bchydro.com's handy CFL fact sheet [PDF, 1.0 Mb] to help you make the right choices when you get to a store with a wide selection of bulbs. And always look for the ENERGY STAR® label, which identifies products that have been tested to meet operating, reliability and energy efficiency criteria.
Not your grade school fluorescent
Today's compact fluorescent light manufacturers offer a wide variety of CFLs that deliver on light quality and convenience as well as energy savings – usually about 75 per cent better than incandescents.
And if you've heard someone complain of a CFL that delivered a light too yellow, too dim or even too bright for comfortable reading, consider this. A 2007 test by Popular Mechanics Magazine that used technical measures as well as the subjective ratings of testers discovered that six of seven CFLs tested against an equivalent incandescent scored higher for reading – and all seven CFLs scored a higher overall grade.
The cost of CFLs
Yes, CFLs are more expensive than incandescents, but replacing a 100-watt incandescent with a 25-watt CFL, for example, will save approximately $30 in electricity over the life of the CFL.
Remember, too, that CFLs last about eight times as long as incandescents – expect to replace them only every five to six years. Given that long life, it's even more important to choose the right light – the one that best suits the situation – for a given room, as that's the bulb you'll be living with for quite awhile.
CFLs and mercury content
Compact fluorescent bulbs do include small amounts of mercury, a toxic metal that can lead to adverse health effects for fish and humans. But with amounts of less than 4 mg of mercury per bulb – about one-fifth that found in the average watch battery and less than 100th found in your typical amalgam dental filling – and convenient access to CFL recycling facilities, the threat is not considered significant.
Some manufacturers, including Philips with its 'Alto' CFLs, offer even lower amounts of mercury in the bulbs.
Three steps to choosing the right CFL
Armed with basic knowledge about colour temperature, bulb shape and lumens, you'll be equipped to make the right choice.
Colour temperature
Many stores have only basic information about colour temperature, a feature that's sometimes a challenge for first-time CFL buyers. Know what to look for, and you'll get the right light.
Colour temperature refers to the shade of white light, identified by correlated colour temperature (CCT) and measured by Kelvin (K). Warmer colours correspond to lower Kelvin numbers, while higher Kelvin numbers indicate a cooler, bluer light.
The majority of CFLs on the market are 2700-3000 K and project soft white or "warm" light. These bulbs enhance warm colours (red, yellow and orange) found in the home.
Bulbs with a slightly higher K rating (up to 3500 K) can be optimal for reading, but as that K rating increases (to 4100, 5000 and 6500K) the effect is increasingly white to bluish light that enhances cooler colours (blue, green, violet). The higher K-rated lights are often referred to as "daylight".
You may also see some bulbs labelled by a CRI (colour rendition index), which indicates how true colours appear under a light. Bulbs with a CRI rating of 60 to 80 are suitable for offices, classrooms and supermarkets, but all Energy Star rated CFLs have a CRI rating of at least 80 and are better for home, retail, restaurant and lobby use.
Bulb shape
Different fixtures require different types of bulbs, and compact fluorescent bulbs come in a variety of shapes and sizes. Check out our CFL fact sheet [PDF, 1.0 Mb] to find the type of fixture you'd like to equip with a CFL, and then decide which CFL works best for you.
Choosing the Right Lighting Level
Look for CFLs that produce the same amount of light (measured in lumens) as the bulb you are replacing. Typically, the following conversions will apply:
|
|
|
|
Incandescent |
CFL |
Light output |
|
40W |
9 – 11 |
400 – 500 |
|
60W |
13 – 16 |
800 – 1,000 |
|
75W |
18 – 20 |
1,100 – 1,300 |
|
100W |
23 – 27 |
1,600 – 1,800 |
* This is an approximate replacement guide only – light output (measured in lumens) will vary with make and model of bulb chosen. Look for the ENERGY STAR logo for an assurance of an accurate equivalency guide.
Where do CFLs work best?
Frequent on and off switching can shorten a CFL's life. To take full advantage of the energy savings and long life of ENERGY STAR qualified CFLs, it's best to use them in light fixtures you use the most and are on for at least 15 minutes at a time. This is not to say you should leave lights on all day.
Good locations for CFLs include:
- family and recreational rooms
- living rooms
- kitchens
- bedrooms
- hallways
- front porches (if you use a CFL outside, check the lamp's packaging for the minimum temperature required for starting)
Because CFLs have a long product life, use CFLs in hard-to-reach places so that they don't have to be replaced as often.
- ceiling pot lights
- accent lighting
- chandelier fixtures
Dimmers and three-way lights
Some CFLs are specially designed to work with dimmers and three-way switches (tri-lights). Check the package to make sure the light is suitable to the specific use.
