Saving Energy in Lighting
Your utility company tried telling you to use more fluorescent lights to save energy, but you hate how fluorescent lights flicker when you turn them on and then make that annoying hum. And they make everything look sort of blue and cold. Isn’t there anything better?
Yes, fluorescent lighting technology has significantly improved in recent years. One such technology is called “electronic ballasts.” You have to specifically ask your lighting store for them. Unlike the older magnetic or transformer ballasts, electronic ballasts eliminate that annoying hum and flicker and allow the bulbs to emit light which is better quality. And instead of slowly getting brighter as they warm up, they turn on instantly.
Fluorescent bulbs are also available now that have better color. When purchasing bulbs there are two things to look for: the Color Rendering Index (CRI) and the Correlated Color Temperature (CCT). The CRI rates the ability of the bulb to render an object’s true color when compared to sunlight. Look for lamps with a CRI of 80 or higher. The CCT refers to the color objects emit when heated to a certain temperature on the absolute temperature scale (Kelvin). The lower numbers correspond to reddish color and the higher to blue-white color. For color similar to incandescent lighting look for CCTs around 2700. Often, the warm, white fluorescent lamps are sold as “kitchen and bath” lamps.
Lamp……………………………. CRI………………………..CCT
Incandescent………………. 90-95………………… 2700
Cool-White Fluorescent.. 62 ……………………… 4100
Warm-White Fluorescent….51 ……………………… 3000
Compact Fluorescent…………82 …………………….. 2700
Halogen …………………….. … 95+ …………………… 2950
Is it better to turn lights off when you leave the room?
That used to be the case with fluorescent lights, but advances in technology, especially in ballasts, have resulted in lights that do not use appreciably more energy to start up. Turning fluorescent lights on and off does slightly shorten the lifetime, in hours, of the bulbs, but you will have to replace the bulbs less frequently if they are not running all day long. Incandescent lights do not require additional energy to start, in any event, so if you are leaving the room for more than a couple of seconds, you will save by turning the lights off, for both fluorescent and incandescent bulbs.
Source: Home Energy Saver - lbl.gov