Traditional incandescent lights are outdated products, very energy consuming. They are phased out - or are being phased-out - in many countries and states.
12 watts CFLs (Compact Fluorescent Lamps) or 12 watts LEDs have the light output of 60 Watts incandescent light bulbs. CFLs and LEDs may come with all the colors and light levels of the old incandescents.
CFLs and LEDs are now available in 'warm' colors, unavailable some years ago, when first introduced.
Types of Low-Energy lights
New light bulbs come in three types: the halogen (sometimes called "energy-efficient incandescent lights"), the compact fluorescent lights (CFL), and the LEDs (Light Emitting Diode).
They have different prices, lifespan and outputs…
Halogen lights are the least expensive of all; their prices are very similar to those of the old incandescent lights…
Compact fluorescent lights (CFL) are a more expensive than halogens, but their prices are decreasing.
And the same is true for LED lights; they are the most expensive of the three, but their prices are expected to decrease significantly over the next few years.
Halogen lights can provide energy savings of about 25%, compared with traditional incandescent bulbs. That’s a lot less than the savings provided by Compact Fluorescents or LEDs: about 75%.
According to the Energy.gov program, upgrading 15 old incandescent light bulbs to CFLs or LEDs can save you about $50/year.
Shapes and fixtures
New bulbs can directly replace common incandescent bulbs in most existing fixtures and screw-based sockets. New CFLs and LEDs use about one fourth the energy of traditional incandescent bulbs. Compared to incandescent, a typical CFL can pay for itself in less than 9 months (for a two hours/day of usage) and will last much longer.If in doubt, take an old bulb to a lighting store and ask for assistance.
Halogen bulbs can last about three times longer than traditional incandescents. Once again that’s good, but a lot less than CFL (the expected life is 10 times longer) and LEDs (25 times longer).
Unfortunately, there are many customer complaints about the lifespan of new low-energy bulbs. Manufacturing details – or the type of lighting fixture – may explain it. New bulbs aren't all made equal, and you should prefer qualified lamps and fixtures (Energy Star).
The colors, the wattage
Many people feel confused about the wattage and brightness of low-energy lamps. They still associate wattage to brightness. But a 25 watts CFL provides about 4 times more brightness than a 25 watts traditional light. Light output is measured in lumens, not in watts.