They join the other eight I’ve received free over the last few years in a box in the garage. One day I hope to find a use for them – but it certainly won’t be for lighting. “Low-energy bulbs” (compact fluorescent light bulbs – CFLs) are the illumination equivalent of a Black Hole – they actually seem to suck light out of a room.
Theoretically, CFLs use up to 75 per cent less electricity than the "light equivalent" incandescent bulb. The UK’s Energy Saving Trust (another quango which wastes more energy than it saves) claims that just one CFL could save up to £7 a year on a household electric bill. Given that CFLs are said to last up to 10 times longer than incandescent bulbs, you could save £60 over the life of one lower-energy bulb.
So ... if you have simple needs and unexacting standards and don’t think of your time in terms of billable hours, you might save a few pounds a year.
A CFL that uses 13-18 watts is supposed to produce the same amount of light as a 60-watt incandescent. However, almost no one believes the "light equivalents" on the packaging of CFLs; lots of websites exist to compare the relative merits of the many brands, manufacturers and styles. In practice, to replace a 60-watt incandescent you need a 100 watt-equivalent (20-watt CFL) for approximately the same lighting level, and for maximum life expectancy you should keep your CFL on for at least 15 minutes each time. Used in the correct manner, the direct energy saving may be much less than claimed – more like 25-30 per cent than 75 per cent.
A number of factors can drastically shorten the life of your CFL bulb and reduce any cost advantage:
- turning on and off too frequently (less than 15 minutes at a time)
- using it upside down (ie, socket "up", light "down" – in this position the heat from the light rises and overheats the electronics)
- fitting it in a recessed or enclosed position (overheating again)
- fitting it somewhere cold (like Britain?!)
- putting it in an incompatible dimmer system (designed for incandescents)
- using it with an electronic timer, motion detector or light detector
- placing it anywhere that vibrates (eg, near a garage door or in a ceiling fan)
Normal incandescent bulbs in the home contribute a surprising amount to ambient warmth. About 85-90 per cent of the bulb’s energy is converted into heat, so the 30-40 to be found in an average four-bedroom house (totalling, say 3,000 watts) could produce as much warmth as a three-bar electric heater. Wholesale replacement of all those bulbs with CFLs will cause a noticeable drop in temperature. If the central heating is turned up there will be additional (mostly gas) energy use. Since 20 per cent of our electricity comes from very-low carbon nuclear power, the switch of fuel sources is not carbon-neutral.
In hotter countries, with air conditioning, the "waste heat" of light bulbs is a greater problem than in the UK, where "waste heat" is something of an oxymoron. CFLs also require considerably more energy to manufacture, but since all that takes place in the Far East, it is not so obvious to your average Green.
Other problems with CFLs include:
- Flickering
- being slow to come on and warm up to full light level
- light levels fade as the bulbs age
- radio-frequency interference with electronic equipment, broadband signal and remote controls.
Although supermarkets are phasing out 150W and 200W incandescent bulbs, they can still be obtained on the web.
Buy now while stocks last!
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