Light Bulb Efficiency


My clients often ask what my recommendations are regarding upgrading from traditional incandescent bulbs to more efficient LED or CFL lights.  Will the upgrade cost of the more efficient light options actually save me money? How do I choose the correct light option?  

 The following is some helpful information and guidance for upgrading light bulbs. 

  Traditional Incandescent Lightbulbs

Traditional incandescent lightbulbs use a lot of energy and approximately 90% of that energy is released as heat. This lost energy is money we are throwing away.  Operational cost for one hour of usage of the 60-watt incandescent light bulb is $2.19 per year.  An average household has two exterior light fixtures with 60-watt incandescent light bulbs in each fixture. Those lights are used ten hours per day on average and cost $43.8 per year to operate.  Out of the $43.8, only $4.38 is used to produce light while the rest is lost to heat. Keep in mind that the above calculation is for only two light bulbs.  Typical incandescent bulbs last 1,000 to 2,000 hours.  Simply put, they waste a lot of energy and don’t last very long.

New energy-saving lightbulbs

The new energy-saving lightbulbs are much more efficient.  Compared to traditional incandescent lights, they typically use 25%-80% less energy and can last 3-25 times longer.  Switching to energy-efficient lighting is one of the fastest ways to cut your energy bills.

There are many choices in energy-efficient lighting. The most popular light bulbs available are halogen incandescent, compact fluorescent lamps (CFLs), and light-emitting diodes (LEDs). Although they can initially cost more than traditional incandescent bulbs, over their lifetime they save you money because they use less electricity.

Halogen Lights

Energy-saving or “halogen” incandescent light bulbs use about 25% less energy than traditional incandescent light bulbs.  The downside of “halogen lights is that their life span is about the same as traditional bulbs. .

CFL Lights

Fluorescent CFL bulbs last about 8-15 times longer and use at least 75% less energy than traditional incandescent bulbs.  A typical CFL can pay for itself in energy savings in less than nine months and continue to save you money each month.

 Fluorescent lights can be divided into two main categories:

  1. Compact fluorescent lamps (CFLs), with integral ballasts and screw bases:  These lights are often used in household fixtures.

  2. Fluorescent tube and circline lamps:  These lights are typically used for task-lighting such as in garages and under cabinet fixtures and in commercial buildings.

 CFLs can provide the same brightness and colors as traditional incandescent bulbs.

More info about CFL’s can be found here

LED Lights

 ENERGY STAR-qualified LEDs use only about 75% of the energy and last up to 25 times longer than traditional incandescent bulbs.  They come in a variety of colors, and some are dimmable or offer convenient features such as daylight and motion sensors.  In addition to standard screw-in bulbs, you’ll find LEDs in desk lamps, kitchen under-cabinet lighting, and even holiday light strings.

According to the US Department of Energy, by 2027, widespread use of LEDs could save about 348 TWh (compared to no LED use) of electricity.  This is the equivalent annual electrical output of 44 large electric power plants (1000 megawatts each), and a total savings of more than $30 billion at today's electricity prices.

 More info about LED’s can be found here

Lumens and the Lighting Facts Label

When buying new energy efficient light bulbs, choose the new bulb according to the brightness you want by comparing lumens instead of watts. A lumen is a measure of the amount of brightness of a light bulb—the higher the number of lumens, the brighter the light bulb.

According to the U.S Department of Energy, the brightness, or lumen levels, of the lights in your home may vary widely, so here's a rule of thumb:

  • To replace a 100 watt (W) incandescent bulb, look for a bulb that gives you about 1600 lumens. If you want something dimmer, go for less lumens; if you prefer brighter light, look for more lumens.

  • Replace a 75W bulb with an energy-saving bulb that gives you about 1100 lumens.

  • Replace a 60W bulb with an energy-saving bulb that gives you about 800 lumens.

  • Replace a 40W bulb with an energy-saving bulb that gives you about 450 lumens.

Lighting Fects Lable.png

The Lighting Facts label, required on all light bulb packages, will help you understand exactly what you are buying and buy the light bulbs that are right for you.  In the past, we bought light bulbs based on how much energy, or watts, they use.  Wouldn’t it make more sense to buy lights based on how much light they provide?

Below is a video by the U.S Department f Energy explaining above stated facts.