Lighting Design

MIT Invention Increases Incandescent Efficiency


As far as efficiency goes, there is not much of a contest between incandescent bulbs versus LEDs. The latter lasts 25% longer and uses up to 80% less energy, and when homeowners, designers and lighting professionals want to decrease energy bills, LED bulbs are the easy choice. However, researchers at MIT have invented a technology that may someday change these well-known facts.

Why are incandescent bulbs so inefficient?

Incandescent light glows warm and is often perceived as a superior light quality to the cooler LED. The bulb uses electricity to heat up a very thin tungsten filament to more than 5,000 degrees Fahrenheit. The filament both glows and radiates heat, the majority of the energy going towards the heat. A normal incandescent bulb uses a mere 2% of its electricity towards light.

The story with LEDs

LED bulbs eliminate the need for a filament, directly transforming electricity into light, through a transistor. This cuts out the need for a filament and the wasted energy towards heat. A 60 watt incandescent light bulb is equal in light to a 12 watt LED. The difference is significant, with LEDs using 5-15% of the energy towards light (compared to 2% of incandescent).

MIT’s reflective solution

A team of researchers at MIT have developed a new kind of incandescent bulb that makes use of the heat energy normally wasted in a traditional incandescent. Using photonic crystals to bounce energy back and forth between a folded ribbon of tungsten, the new design is three times more efficient than its predecessor, and more efficient than some of the less efficient LEDs on the market.

MIT’s reflective solution is far from market ready, and does not solve the issue of product life, as the filament is still prone to breaking from such intense heat. However, this step towards efficient lighting options shines the light on a possible future not fully tied to LED technology.