The humble light bulb just became 300% more efficient

Hipster coffee shops, sandwich bars and almost everywhere in Shoreditch can rejoice as their old-timey light bulbs of choice may have just become 300% more efficient.

The humble light bulb just became 300% more efficient

The news comes from a team of MIT professors who have found a way to transfer the energy lost from heating a bulb’s tungsten filament back into light. In a process called “light recycling”, these modern filament bulbs will be able to harness the lost energy and convert most of it into boosting the bulb’s output.

Traditional bulbs haven’t changed an awful lot since Thomas Edison revealed his incandescent light bulb in 1879. Because of that, a massive 95% of the energy used to create light is actually lost to heat; as a method of lighting anything, filament bulbs are by far the most inefficient way to do so. The UK and Europe have made efforts to switch away from such inefficient lighting and instead opt for fluorescent, halogen or LED bulbs, but this technological breakthrough could put incandescent lights back in business.

“Light recycling” is, in theory, very simple. You have a standard tungsten filament, but it’s encased within a “secondary structure” to reflect lost infrared radiation back onto the filament to be absorbed and reproduced as light.


As simple as that process is, it makes a huge difference to an incandescent bulb’s energy use. While a conventional bulb has a luminous efficiency of just 2 to 3%, with fluorescents reaching 7-15% and LEDs at 5-15%, these new two-stage incandescent bulbs could deliver up to 40%.

These proof-of-concept bulbs don’t quite reach those heights of energy efficiency yet, however, reaching just 6.6%. Even such a low result is more than some LED bulbs on the market, though, and close to what a fluorescent bulb could produce.

Interestingly, the three professors involved in the research didn’t set out to produce more efficient light bulbs. Instead they set out to find ways to control thermal emissions and reuse them to improve general efficiency. Hopefully we’ll still see these incredibly efficient incandescent bulbs come to market in the coming years.

Now read this: The world’s smallest light bulb is an atom thick

Image: Filip Mishevski – Flickr

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