Energy Efficient Light Bulbs
There are three main types of light bulb:
- Standard or incandescent bulbs
- Energy efficient bulbs aka compact fluorescent lights (CFLs)
- LED lighting – light emitting diodes
How they work
- Incandescent bulbs create light by heating a filament inside the bulb; the heat makes the filament white-hot, producing the light that you see.
- CFL bulbs on the other hand, contain a gas that produces invisible ultraviolet light (UV) when the gas is excited by electricity. The UV light hits the white coating inside the fluorescent bulb and the coating changes it into light you can see.
Generally CFLs last 8-12 times longer than incandescents. LEDs last 5 times longer than CFLs and 60 times longer than incandescents.
There are two main issues with light bulbs:-
Saving energy
CFLs provide 75-80% energy savings. An incandescent wastes 90% of its energy generating heat. In comparison to using 100-watt incandescents, one 27-watt CFL can save 730,00 watts over its life-time (enough to power an average home for a month).
Reducing Pollution
As CFLs have a longer life (generally the life of one CFL is equal to 8 incandescent bulbs) there is less waste. Also CFLs contain mercury, but in extremely small amounts, so there is less harmful waste product (The mercury from one fluorescent tube light can pollute 30,000 litres of water beyond a safe level for drinking).
Recent developments in LED have reduced their price and have expanded the application of how they are being used. LEDs provide focussed light and therefore are best as 'task specific lighting' such as reading lights, desk lamps, night lights, spotlights, security lights, signage lighting, etc. They do not radiate light in 360 degrees as an incandescent does so the light will be bright where only where you point it. This technology is currently being developed and it will be interesting to see what developments are coming for more residential applications of LED lights.
A guide to replacing incandescent bulbs with CFLs
• 60 watts incandescent = 15 watts compact fluorescent
• 75 watts incandescent = 20 watts compact fluorescent
• 100 incandescent = 26-29 watts compact fluorescent
• 150 incandescent = 38-42 watts compact fluorescent
• 250-300 incandescent = 55 watts compact fluorescent
