Light bulbs aren’t what they used to be. Fortunately, that’s because they’ve improved in many ways. In the first part of our series on light bulbs, we described the main types of consumer light bulbs available today (CFL, LED, incandescent, and halogen). All of these bulbs have been made more energy efficient than older incandescent bulbs, and there are actually more options available in these new light bulbs—if you know what you’re looking for.
Unfortunately, knowing what you’re looking for is more complicated than it used to be. To buy an incandescent bulb, you only needed to know what wattage to buy. Some companies produced bulbs with slightly different light characteristics, but any incandescent bulb with the right wattage would work.
Part of the updated energy standards regarding light bulbs requires bulb packaging to provide more information regarding the light produced and the energy consumed. There’s more to read and digest than a simple wattage number, but when you understand the new information, it will help you choose exactly the right bulb for your needs.
With old fashioned incandescent bulbs, people equated the wattage of the bulb with its brightness. Higher wattage incandescent bulbs do produce more light, but wattage is actually the amount of electricity consumed, not the amount of light produced. Modern packaging is changing to use the correct term for units of light, which is lumens.
Just like with wattage in old bulbs, a higher lumen count means a brighter bulb. To buy an equivalent bulb to an old incandescent, you need to know how many lumens such a bulb typically produced:
- 40-watt bulb: about 450 lumens
- 60-watt bulb: about 800 lumens
- 75-watt bulb: about 1,100 lumens
- 100-watt bulb: about 1,600 lumens
When you get used to thinking in lumens rather than watts, you’ll discover that you actually have a greater degree of control over your lighting. For example, if you want a slightly brighter bulb in a lamp, you can specifically look for a bulb with a higher number of lumens, rather than guessing which 60-watt bulb would be the brightest.
Temperature, sometimes called color temperature, is an indication of how warm or cool the light appears to be. This is an area where the earliest energy-efficient bulbs fell short of expectations, and a lot of work has been done in the past several years to improve this area.
Traditional incandescent bulbs generally produced a warm, slightly yellow light. In temperature terms, this is a “low” temperature light. On the other end of the scale are bulbs which produce a bright light which may have a blue tint. These are “high” color temperature bulbs. In areas where you want warm light such as that produced by incandescents, look for bulbs with lower color temperature. Task lighting may benefit from using higher color temperatures for a whiter light. Once you have a feel for the new terminology on the packaging, you can adjust lighting to suit your preferences by choosing bulbs with the right color temperature.
As we’ve already mentioned, watts are a measurement of electricity. In incandescent bulbs, the wattage was a good indicator of brightness because all bulbs worked in essentially the same way. With multiple types of bulb technology available now, watts are no longer a reliable measurement for how bright a bulb is. But watts are still important for understanding how much a light bulb is costing you in electricity. To save on energy costs, look for bulbs that produce a high number of lumens per watt. The higher the ratio, the more efficient the bulb.
Understanding Color Rendering
Light can greatly affect how colors look. Sunlight is the best type of light to show true colors. The Color Rendering Index number of a light bulb compares how true colors look in the light produced by the bulb, compared to the true colors as seen in sunlight.
The color rendering number is most important for bulbs that produce a natural, white light, as bulbs with a warm yellow tint or a cool blue tint will have a stronger effect on colors regardless. Look for a CRI number of 80 or above for good color reproduction.
Finally, new types of bulbs may have some limits that didn’t apply to incandescent bulbs. LED bulbs, and to a lesser degree CFL bulbs, have larger bases that can block some of the light produced. This is not a problem for spotlight bulbs, but a big problem for lamps designed for bulbs that emit light in every direction. Look for the term “omnidirectional” to find a bulb that is not seriously limited by directionality.