It’s important to understand lighting cost, energy conversion and color basics before going all-in.

Cost is measured not only in the cost per bulb, but in how often the bulb needs to be replaced. While LED costs the most, to provide 50,000 hours of light, you need only one LED, five CFLs and a whopping 42 incandescents.

You also need to consider energy conversion. To produce 50,000 hours of light, LEDs need between 300-500 kilowatt-hours (kwh) of electricity, while compact fluorescents need 700 kwh. Incandescents once again top the charts at 3,000 kwh.

Color is also critical. Light color is often measured using the color rendering index (CRI), which is a value between 0 and 100. The closer to 100 a light scores, the better it accurately reproduces the natural colors of an object. Sodium-based streetlamps are a good example: They score only 25 on the CRI because they make everything look red-orange. Consumer-grade interior lights rate between 60 and 100, but that isn’t the whole story.

Light temperature, a subset of color, also affects appearance. This temperature is measured in degrees Kelvin, with 2,700 K the standard for the familiar, soft glow of incandescent bulbs. Lights with higher energy efficiency typically come with higher temperatures, in the range of 5,000-5,500 K.

CFLs were designed specifically to replace incandescent bulbs. Most fit into the same size light socket as their incandescent counterparts. They contain two essential components: a curved tube lighting tube and compact electronic ballast.

An evolution from the humming, overhead fluorescent lights found in many office buildings, CFLs need only 1/5 to 1/3 the electricity of incandescents to produce the same amount of light, and they last approximately 10 times as long.

These lights do contain mercury, however, making disposal more complicated and placing some groups (like young children or pregnant women) at risk if the bulb is damaged. Some people have complained that these bulbs produce light that washes out natural colors and makes homes seem pale or sterile, although new designs combat this issue.

LEDs are the most recent contender in the lighting market. These compact bulbs have been used for years in Christmas decorations and children’s toys, but they’re becoming popular for whole-home lighting as well.

These bulbs contain no filament and no mercury or other toxic materials; instead, they use diode chips encased in a plastic. When electricity passes through the diode, its electrons become excited and release light, but virtually no heat. As a result, these bulbs are up to 85 percent more efficient than incandescent bulbs and 10 percent more efficient than CFLs.

On the downside, they cost 10 to 30 times as much as competing bulbs, though they last longer. While they can now replicate incandescent light temperature, these bulbs may have problems with older sockets and may flicker or refuse to turn on when used with a dimmer switch.