A startup is selling a new kind of energy efficient light bulb that costs half as much as a light emitting diode (LED) and, unlike compact fluorescent light bulbs (CFL), contains no mercury. The light bulb works like a cathode ray tube television: it emits electrons that light up a coating of phosphors on the inside of the bulb causing them to glow. The company says that the bulbs are more efficient than either CFLs or LEDs. To keep up with the alphabet soup theme for lighting technology, the new bulbs are called ESLs (for electron stimulated luminescence).

The first bulb, developed by Vu1 Corporation, is the equivalent of a 65-watt incandescent flood bulb and costs $20. They can be ordered directly from the company here. A version of the bulb that looks like a conventional incandescent bulb will go on sale later this year.

Mercury from compact fluorescent light bulbs is an issue, but it’s not as bad as the company makes it sound in a press release. Although mercury in high enough doses can cause health problems, the amount of mercury in a CFL is relatively small—just 4 milligrams compared to 500 milligrams in old mercury-containing thermometers. Because burning coal releases mercury in to the atmosphere, using CFLs, which can reduce electricity consumption, actually decreases the amount of mercury released to the atmosphere, according to the EPA. While Vu1 says that the EPA recommends airing out a house for 24 hours if a CFL breaks, that’s dated information. New EPA guidelines recommend airing out a room for 5 to 10 minutes before cleaning up the bulb, and then for “several hours” after it’s cleaned up.

Still, having a bulb you can just throw away in ordinary household garbage would be nice. Not that you should have to throw many of the new bulbs away–they’re meant to last 10,000 hours.