Switching light bulbs to save energy and money? Today in Part I of our series on fluorescent bulbs, you'll learn scientifically what makes them a better deal. A regular incandescent light bulb has a thin wire made of tungsten housed inside its glass shell. As electricity runs through this filament, resistance makes it heat up and glow. While it provides light, the heat is wasted energy. A fluorescent bulb has a sealed tube containing mercury vapor suspended in argon gas. Electrodes at both ends of the tube send electricity through the gas. These electrodes bump into the mercury atoms, creating ultra-violet photons. These photons, in turn, excite a phosphor coating on the glass -- creating a bluish visible light. So, what makes these bulbs better? Incandescent bulbs produce only 15 lumens of light per watt. Fluorescent bulbs produce 50- to 100 lumens per watt. Thus a 15-watt fluorescent gives as much light as a 60-watt incandescent. More light for less money (and they last longer too.) And that's the On The House tip for today.