Lighting - saving energy

Best choice

Electric lighting is the best option, especially if compact fuorescent light bulbs are used. Paraffin lamps are cheap to buy, but costly to use and the quality of light is not good enough for reading or studying. Candles are dangerous as they are a common cause of fire.

Compact Fluorescent Light Bulbs (CFLs)

CFL bulbs convert 80% of the energy they use into light, and only 20% into heat. Incandescent (traditional) bulbs convert 20% of the electricity they need into light and 80% into heat. Although CFL bulbs cost three to five times more than normal incandescent bulbs, they last six to ten times longer and are therefore cheaper than traditional light bulbs. No special fittings are needed – simply replace your existing bulb with a CFL.

CFLs are found in all supermarkets and hardware stores. The prices for CFL bulbs vary according to shape and wattage.

Installing an 11 watt compact fuorescent light (CFL) in place of a 60 watt incandescent light bulb will save about 570 kWh over the life of the CFL – saving about 570 kg of carbon dioxide during its ten-year lifetime. If every household in Cape Town did this, we would reduce the amount the carbon dioxide released into the atmosphere by 313 500 tons over 10 years. This also means that peak demand would be reduced by a substantial 40 megawatt (MW).

Some things to watch out for

  • When your CFL bulb burns out (in six to ten years), try to find a collection point near you for recycling, otherwise throw it away wrapped in a plastic bag to protect the environment as it contains mercury.
  • Most CFLs cannot be used with dimmer switches.
  • Avoid using CFL bulbs in bathrooms as steam damages the electronics inside.
  • CFLs make their biggest energy savings when they are left on for at least two to three hours a day. In a room where they are regularly switched on and off, a CFL will make little difference to electricity consumption.
  • They also take about five minutes to reach their full brightness.
  • CFL bulbs must have enough space around the attachment for air to circulate.
  • Do not plug CFL bulbs into light-activated adapters – it shortens the life of the bulb and the adapter.
  • Get a CFL with a built-in sensor.

LED cluster bulbs

LED cluster bulbs represent the latest in cutting-edge lighting technology – with a lifespan of 15 to 20 years and drawing as little as 1,08 watt per bulb (a 95% saving per bulb as compared with an incandescent bulb). To match the expected lifetime of a single LED cluster bulb you would have to purchase at least 50 incandescent bulbs.

LEDs come in a variety of colours for mood lighting effects. Unlike traditional bulbs that make use of coloured glass, in the case of an LED it is the wavelength of the light that makes the difference. Though this field of technology is developing fast, LEDs are still fairly costly and are currently used for task lighting (above a desk or painting) and decorative lighting.

source: SMART Living Handbook

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