Greenhouse effects: Light bulbs

Tony Juniper
The vast majority of the 600m or so light bulbs in British homes are of the old-fashioned tungsten filament kind. This won’t be the case for long.
Recent legislation means that these bulbs, which are incredibly inefficient — only about 10% of the power used produces visible light, the rest is heat — will be consigned to the recycling bin. From September 2011, 60W clear incandescent bulbs will be outlawed, followed by a ban on all remaining incandescent bulbs in September 2012.
Instead, homeowners are using lower-wattage halogens, new compact fluorescents and, more recently, light-emitting diodes (LEDs), which all offer good energy-efficient alternatives.
LEDs are semiconductors that convert electrical energy directly into light. This means they require far less energy. The early generation of LED bulbs gave a low-intensity coloured light and were used in displays for calculators, televisions, watches and traffic lights. Now they are brighter and available in many colours, including high-intensity white light. They are compact and robust, light up fast, can be dimmed, produce little heat, and have long lives (more than 25 years for many).
That said, a report published last week by the Institution of Engineering and Technology found that the quality of light that energy-saving bulbs produce becomes significantly dimmer over time, losing up to 22% of their brightness. For more advice on what will suit you, visit The Energy Saving Trust (energysavingtrust.org.uk) for a rundown of the various types of energy-efficient bulbs, which can cut your electricity bill by as much as 20%.
We have replaced the 10 35W halogen bulbs in our kitchen ceiling with 3W LEDs, reducing the electricity used by more than 90%. While LED bulbs are much more expensive than regular bulbs, the cost should be recovered within two to three years.
In September, Philips launched a range of retrofit LED bulbs for the home (consumer.philips.com/c/led-light/19964/cat/gb). These are designed to fit the most common bayonet and screw light fittings found in the home and are suitable for replacing old bulbs of up to 40W equivalent. We plan to install them in the rest of the house.
Tony Juniper is an environmental campaigner and former director of Friends of the Earth; tonyjuniper.com