Energy-saving bulbs and lighting: bulb technologies, efficiency, advantages and disadvantages

Keywords: bulb, compact fluorescent, compact fluorescent, reduction consumption, savings, economy, lighting, led

When Philips replaced the 10 or so incandescent bulbs illuminating the Eiffel Tower with CFLs, the electricity bill of one of the world's most visited monuments was reduced by 000%.

This saving is also possible on your EDF bill without reducing the quality of the lighting.

Different technologies exist to replace the good old tungsten bulb. To compare them, we measured the ability of new bulbs to transform electrical energy into light rather than heat. Efficiency that is measured in lumens / watt, or the amount of light produced at a given electrical power and which varies according to the technology used.

Lighting Technologies

Tungsten bulb (Yield approx: 10-15 lumens / watt)

Conventional bulbs use a tungsten filament whose incandescence (rise in temperature and therefore radiation of hot materials in the visible spectrum) causes light. Over time, tungsten weakens. The filament then eventually breaks and must be replaced!

Lifespan: 1000h on average. They are available in a power range from 25 to 100 watts. In "Globe" format most of the time.

Advantages: very inexpensive and good color rendering.
Disadvantage: low service life (1000h) and high energy consumption.

Halogen bulb (Yield approx: 14-20 lumens / watt)

To limit the evaporation of the tungsten and therefore maintain the optimum brightness during the life of the bulb, one method consists in surrounding the filament with a halogen gas. The concentration of heat allows better brightness, doubling the life of the bulb but also its price. Years.

Lifespan: 2000h on average. Available in a very wide range: from 20 to 2000W. Attention are prohibited more and more.

Advantages: quite inexpensive and very good color rendering.
Disadvantage: low service life (2000h) and high energy consumption.

Neon tube or Fluorescent tube (Yield approximately: 50-60 lumens / watt)

Tubes filled with gases such as mercury or krypton are excited by an electric discharge and emit ultraviolet light which transforms into visible light thanks to the particles located on their walls. Neon's long, tubular shape is four times more efficient than conventional bulbs and has a long service life.

Lifetime: 5000 to 10 000h.

Advantages: long service life, energy saving.
Disadvantages: more difficult assembly (tube, choke and ballast stabilizer), white and cold light (disadvantage to live but advantage to work).

Fluo-compact bulb (Yield approximately: 50-60 lumens / watt)

Fluorescent bulbs are now available in various forms known as CFLs, which have lost space and gained endurance, reaching up to 15 hours of functionality. Be careful though: these models take several minutes to reach their full power and diffuse a light different from that of conventional bulbs!

Advantages: long service life (5000 to 15 000h), energy saving and very little heating.
Cons: takes a while to light up at maximum brightness.

LED bulb based on light emitting diode (Yield approx: 80-150 lumens / watt)

The white light-emitting diode that appeared in the late 1990s made it possible to create LED bulbs for household lighting. The first 220V LED bulbs had a lower efficiency than the compact fluorescent (20 to 40 lm / W only at the beginning) but the evolution was rapid (SMD LED, Cree ...) and quality LED bulbs have, in 2020, a yield that easily exceeds 80 lm / W. Some even test the 150 lm / W (beyond that, beware the characteristics are certainly exaggerated). Interestingly, LEDs can now have very varied colors: from 1800K (color of a candle flame) to 6500K (color of light, white, sun) and can take all the colors of the rainbow, with RGB LEDs.

Lifespan: 10h to 000h. See our experience: actual lifespan of an LED bulb (long lasting experience)

Summary of the light output of household bulbs

• Incandescent bulb Tungsten base: 10 to 15 lm / W
• Incandescent bulb halogen base: 14 to 20 lm / W
• Fluorescent tube: 50-60 lm / W
• Fluorescent bulb (compact: 50-60 lm / W
• LED bulb: 80-150lm / W (in 2020)