There's a nice article in this week's New Scientist on the imminent replacement of incandescent light bulbs by compact fluorescent lamps (CFLs). Whilst the incandescent bulb only converts 5% of its electrical energy to light, the CFL converts 15%. CFLs are currently about 5 times more expensive than bulbs, but last 10 times as long, so already constitute both a cost and an environmental saving. What the article doesn't mention is that CFLs emit quite significant electromagnetic radiation in the radio frequency range. Those people I know who have tried CFLs in their own home, say that they interfere with other electrical devices such as the radio, and even have a tendency to spontaneously change television channel for you!