Do Light Bulbs Really Make a Difference? Yes!

From Scott Carlberg

Light bulbs, small as they are, make for big energy savings. New light-emitting diode (LED) bulbs use some 80 percent less electricity than old incandescent bulbs. LEDs are more efficient to the point that they helped US electric usage flatten and sometimes decline over the years.

Why does such a small item like a bulb make such a big cumulative change? “No other household technology is as disruptive as lighting,” said Lucas Davis from the Haas School of Business at the University of California, Berkeley. “Incandescent bulbs don’t last long, so the installed stock turns over quickly. Air conditioners, refrigerators, dishwashers, and other appliances, in contrast, all have 10+ year lifetimes… The turnover is too slow, and the gains in energy-efficiency for these other appliances have been too gradual for these changes to explain the aggregate pattern.”

For decades incandescent bulbs were the standard. Light is produced by that burning hot resistance in a filament. I once heard old incandescent bulbs called heat machines that happen to make light. Energy intense.

A guide from old to new light levels

Big difference now. LED lighting is different from other lighting sources such as incandescent bulbs and CFLs (compact florescent lights). Differences include the following:

  • Light Source: LEDs are the size of a fleck of pepper, and a mix of red, green, and blue LEDs is typically used to make white light.
  • Direction: LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light. This feature makes LEDs more efficient for many uses such as recessed downlights and task lighting. With other types of lighting, the light must be reflected to the desired direction and more than half of the light may never leave the fixture.
  • Heat: LEDs emit very little heat. In comparison, incandescent bulbs release 90% of their energy as heat and CFLs release about 80% of their energy as heat.

“Swapping out five bulbs will save you about $35 a year …the average house has 30 to 60 light bulbs,” quotes a USA Today story. That can take the sting out the higher cost of an LED bulb. Some utilities have even reduced cost LED bulbs for customers, too.

Consumers bought incandescent bulbs according to watts, which indicates how bright a bulb was. More watts, brighter. Not so with LED bulbs, though. Look for lumens instead. Lumens have been around for a long time, just not used in consumer lighting. It measures how much light a bulb emits.

Here’s a general guide to comparing old-style watts to LED lumens:

  • Old 60 watts would be roughly 800 lumens
  • Old 100 watts would be roughly 1,600 lumens
  • Old 150 watts would be roughly 2,600 lumens

Though LED bulbs may not be familiar and are more complex, there’s help. A label. “When you shop for light bulbs, you’ll also want to think about light appearance, or color temperature. Light appearance ranges from warm to cool. Warmer light looks more yellow, like the light from a traditional incandescent bulb, cooler light appears more blue.” (Source)

The Lighting Facts label on the package tells you a lot about a bulb:

  • Brightness (in lumens)
  • Yearly estimated energy cost
  • Expected bulb life (in years)
  • Light appearance (how warm or cool the light will look)
  • Wattage (energy used)
  • If the bulb contains mercury

Lots of people, making the same small effort many times, like changing a light bulb, can add up. It can even add up to the point that can eliminate the need for a new power plant. That saves customers’ money, too.

Good combination. Brighten up your home, lighten up your electric bill.