To replace your incandescent light bulbs, there are three groups of more energy-saving alternatives:

• new generation halogen light bulbs;
• compact fluorescent light bulbs (also known as “economical bulbs”);
• LEDs.

See also: 'How to choose the appropriate light bulb?'

These lights bulbs are available in various sizes and capacities. Most of them exist in two versions:

• either they are designed for new types of light fittings created especially for them;
• or they are designed with a standard screw base and in a size that makes them compatible with old light fittings. They can therefore simply replace an incandescent light bulb which is no longer available for sale.

Three main groups of more economical bulbs

1. High-performance halogen light bulbs

They operate according to the principle of incandescence, but their lifespan is longer and their energy performance is better. There are two types:

• C-class halogen lights bulbs contain xenon, a gas that slows the wear and tear of the filament and reduces the heat loss. They therefore use 20 to 30 % less than a conventional incandescent bulb. They operate on 230 V alternating current.
   
• B-class halogen light bulbs are even more efficient. Thanks to the coating on the inside of the bulb, which reflects the infrared rays, and to their spherical shape, it takes less energy to heat the filament. They therefore use 45 to 30% less than a conventional bulb. They operate on low-voltage continuous current. They therefore require a transformer, either external or integrated into the light fitting, or miniaturised and integrated into the light bulb itself.

This type of bulb is available with a screw base, which means that incandescent bulbs can be replaced while using less electricity and maintaining the quality of the light. In addition, the light given off can still be adjusted (dimming).

2. Compact fluorescent or “economical” light bulbs

They have been around for about thirty years now. In fact, they are miniature ‘neon tubes’. Three types of these are available on the market: straight tubes folded back at the end, spiral tubes and globes (these are the most similar to incandescent bulbs).

As their name indicates, “economical” bulbs are very energy saving: they use 65 to 80% less than a conventional light bulb! Moreover, the ones found in shops are all A-class bulbs. And they last far longer (around 10,000 hours compared with 1,000 hours for an incandescent bulb). The base of these bulbs is identical to that of incandescent bulbs so they can be used to replace the older bulbs almost everywhere (except if the space available in the light fitting is really too small: be sure to check the length). N.B.: many compact fluorescent bulbs are not “dimmable” (in other words: you cannot vary the light intensity.

Finally, if they seem to take a little more time to light up, note that fast start light bulbs are now also available. However, it is best not to use these in rooms where lights are switched on and off frequently and for short periods of time.

3. LEDs (light-emitting diode)

These diodes are tiny and use up to 80 % less energy than an incandescent bulb, while they have a lifespan of tens of thousands of hours. What is more, LEDs light up instantly and are resistant to shocks and vibrations. Another advantage is that they are available in a wide range of colours.

At the moment LEDs tend to be used more for mood lighting, but thanks to their capacity they can already replace the old 60 W bulbs. They may eventually be able to replace others as their performance is improving regularly.