What you should know
o Before buying, be sure you know where and how the light bulb is going to be used: in a ceiling lamp, a floor lamp, a table lamp; as a main source of light, or indirect light
o There are light bulbs in myriad shapes and tones; these factors influence the decoration and atmosphere of the home.
o Not all bulbs have the same power or intensity. You should know how much you need, depending on the area you want to light and if you are going to use the light to read, for example.
o All of these factors will influence how much you spend and how much energy you save. It is pointless to buy a powerful lamp if need only a bit of light.
o Light bulbs have different nozzle sizes so you should buy the right one. They are measured by their diameter: E 14 (thin) and E 27 (wide)

Conventional incandescent light bulbs
o These are the most traditional and common ones. They turn on and off instantly.
o They are based on a tungsten filament, which lights up when heated.
o They can be transparent or come in a variety of finishes: emery glass or tones which avoid glare and provide for a softer atmosphere.
o Different varieties of incandescent bulbs include reflective bulbs, which project indirect light; opalescent light bulbs which have opaque glass hiding the filament. They are not as bright as other bulbs, but do not glare.
o Incandescent bulbs turn only a small portion of the energy they consume into light.

Fluorescent tubes
o The most traditional is the long tube, although there are more and more designs these days. They last from 7,500 to 12,000 hours.
o They emit bright white light as a result of flow of mercury vapors. They are especially useful in kitchens or work areas as long as they are turned on at least three hours a day.
o They consume less energy than incandescent bulbs. But as a rule of thumb these lamps last longer if they are turned on and off less frequently. When the bulb wears out, it changes color. If the lamp has two bulbs side by side, it is best to change both at the same time.
o As they emit cold light, they are not recommended for areas dedicated to rest and relaxation.
o They do resist the cold well, and when necessary should be protected with glass. They normally have a ground.
o Modern fluorescents have instant turn-on mechanisms.

Halogen light bulbs
o These are based on incandescence, but with the added feature of a halogen gas which keeps the filament from wearing out.
o They emit a lot of heat, so keep in mind the characteristics of the lamp you will be using before buying this kind of bulb.
o Halogen light bulbs with screw-in nozzles can be used where you currently have incandescent bulbs, but don't forget the precautions noted above.
o Halogen spot lights, regardless of whether they are embedded or not, and similar lamps such as bathroom or reading lamps, need a current transformer because they work at low voltage, i.e. 12 volts. Sometimes the transformer is incorporated into the lamp.
o Halogen lamps can be seen as consuming less because for the same power as other bulbs they emit more light. Plus, they last between 3,000 and 5,000 hours.
o Be careful when handling them. They emit so much heat they can cause burns.

Low-consumption light bulbs
o They consume less energy and last much longer than traditional bulbs.
o The system is similar to that of fluorescent tubes but incorporates an electronic circuit in the bulb itself. They fit in any socket of the same size.
o They are more expensive, but over time and with the energy saved they turn out to be cheaper. It is estimated they last eight to 10 times longer than normal incandescent bulbs. A 25-watt bulb is equivalent to a 100-watt incandescent bulb.
o Use recommended in areas that need many hours of lighting.
o Remember that this kind of bulb generally cannot be used with dimmers.
o Like fluorescent and halogen bulbs, they are most appropriate for home use.
o They emit cold white light and are now available in many different models, making these bulbs very decorative.�