By far the most common type of electric light bulb is the General Lighting Service (GLS) Bulb or Standard light Bulb. These are capable of providing different levels of light or brightness - indicated by the wattage - and can be used for ceiling lights and lamps. They have a tungsten filament and will last for about 1,000 hours.
Bulbs come in a variety of shapes, such as golf ball, globe or candle. Clear light bulbs will create a bright light while opaque bulbs will produce diffused light, therefore different lighting effects can be achieved in different rooms. Bulbs also come in different colours for decorative and festive lighting. There are even bulbs for improving working conditions such as white glare-resistant bulbs in areas where computers are being used.
These last much longer than standard bulbs and emit a crisp, white light. They can be used in most lamps and light fittings including reflectors and uplighters.
Low-energy bulbs consist of small fluorescent tubes fitted with either a bayonet cap or Edison screw cap, so they can be used in place of standard light bulbs. They last up to 12 times longer than standard bulbs operating on a fraction of the electricity. Like all fluorescent lighting, they cannot be used with standard dimmer switches. If opting for low-energy bulbs you will need to know the comparative wattage of low-energy bulbs and standard light bulbs.
Fluorescent tubes need fluorescent light fittings that have a starter. The long white tubes emitting a sharp, clinical light are commonplace but coloured tubes that provide a much softer light are now available. Fluorescent tubes are available in a range of lengths and three sizes: T5 16mm (5/8in) diameter; T8 26mm (1in) diameter; and less common today but still found in some older properties T12 38mm (1 ½ in) diameter.
Originally used for indicator lights on the control panels of vehicles and electrical appliances, LEDs have been developed to produce a strong bright light and are now being used as a low voltage light source. The advantages of LED lighting include: