A few years ago, my son asked me whyv there is so much interest in thecspiral bulbs. I replied for energy conservation. He asked "how so"? I explained the energy lost through the spirals was less, as they produced less heat to give the same light.

He concluded in a way that had me stumped. He said, "I guess you will have to turn the furnace up in colder weather, to compensate for the heat lost?"