Energy Efficient Substitutes For Incandescent Bulbs

Energy Saving Light Bulbs: CFL vs. LED

Homeowners today are shifting towards more cost efficient and eco-friendly solutions for managing energy consumption in their homes. Proper lighting improves the appearance and safety of a home both inside and out, yet it can also account for nearly 25% of a home's electricity. Most people don’t realize that the standard incandescent bulbs they’ve been using for years are only 10% efficient; meaning only 10% of the electricity they use is transferred into light and the rest into heat! Fortunately, the push for a greener way of life has brought rise to two major alternative options for standard incandescent light bulbs: the compact fluorescent light bulb (CFL) and a light emitting diode light bulb (LED). Knowing what to look for and the difference between the two will help the average consumer save energy dollars each month.

CFL Lighting

As a replacement for your average screw in light bulb, CFL bulbs are an excellent option. In simplest terms, CFLs are a miniature version of the common fluorescent light, using an electrical current to make phosphor gas glow. Older CFLs use magnetic ballasts which usually cause a delay and/or flicker when they are turned on, however most new CFLs use electronic ballasts that eliminate this. When compared to incandescent bulbs, CFLs are approximately four times as efficient; a 25 Watt CFL will have the same light output as a 100 Watt incandescent. They also last up to 10 times longer, meaning that over the life of a standard CFL, you would expect to have used 10 incandescent bulbs. Unlike a regular fluorescent light, a CFL gives off light that looks just like a standard incandescent. Choosing the bulb design that best suits the application is also a factor; available form factors include spiral, triple tube, standard, globe, flood and candelabra style bulbs to name a few. While the purchase price of a CFL is typically 3 to 10 times greater than that of an equivalent incandescent bulb, over the lifespan of the bulb you can expect a large return on energy savings (see comparison chart below). Continuously turning a CFL bulb on and off, or exposure to outdoor elements, can reduce the expected life span, so consider where you will be using them. While dimmable CFLs and CFLs that can be used with timers are available, they may not always work with dimmer switches, dimmer modules, or timers. Lastly, CFL bulbs contain trace amounts of mercury which is a toxic metal, and although they can be disposed of in your regular trash, caution should be taken if a bulb is broken in your home.

LED Lighting

Recently, advances in technology have given rise to LED lighting as a replacement for the traditional incandescent bulb. LEDS are small, solid light bulbs which drive their light in one direction or in cones of varying width depending on the bulb design. Traditionally this type of directional lighting has been used for task lighting, flashlights and headlamps. However, grouping these light in clusters and applying new designs have led to the LED as an extremely energy efficient replacement for the standard incandescent bulb. An LED style bulb will generally last approximately 100 times as long as an incandescent; meaning that over the life of a standard LED style bulb, you would expect to have used 100 incandescent bulbs! When compared to incandescent bulbs, LEDs are approximately six times as efficient; in simplest terms a 16 Watt LED style bulb will have the same light output as a 100 Watt incandescent. An LED style bulb can be upward of 50 to 100 times the cost of standard incandescent bulb (although costs continue to drop), but you can expect a large return on your investment do to the lifespan and energy savings when compared to an incandescent bulb (see comparison chart below). Another great feature of LED style bulbs are their durability; because they don’t have a filament they can withstand jarring and bumping making them less likely to be damaged under circumstances when a regular incandescent bulb would be broken. When used with a dimmer, LED bulbs can brighten and dim fairly consistently from 30% brightness up. They will also work well with most timers. On the low end, instead of going completely off, LEDs tend to exhibit a slight glow due to the small amount of current that LEDs require to illuminate. Because this type of alternative lighting is still at the beginning stages, you can expect the capabilities of LED style bulbs to grow.

Understanding Lumens

When replacing a standard incandescent bulb with a CFL or an LED as an alternative, one of the most important factors to understand is lumens. A lumen is a measurement of how many foot-candles of light a bulb puts out in a square foot of area…or in laymen’s terms, how bright a bulb is. Many CFL and LED bulbs are misleading, whether intentional or unintentional, when describing the bulbs they replace. If you want a CFL or and LED bulb to replace your existing incandescent, make sure that the lumens match up.

Comparison Chart

Bulb TypeLumensWattsInvestmentConsumptionEnergy CostTotal Cost
Incandescent1600100$100.0010000 kWh$1,000.00$1,100.00
CFL160025$100.002500 kWh$250.00$350.00
LED160015$100.001500 kWh$150.00$250.00

Investment based on:

  • Incandescent: $1.00 per bulb x 100 bulbs to equal the lifespan of one LED style bulb
  • CFL: $10.00 per bulb x 10 bulbs to equal the lifespan of one LED style bulb
  • LED: $100.00 per bulb equal to 100,000 hour lifespan

Consumption based on:

  • Kilowatt hours (kWh) of energy used over the course of 100,000 hours

Energy Cost based on:

  • 10 cents per kWh average fee from utility company


Incandescent bulbs still make up a majority of the light bulbs in homes today, but as more people become energy and environmentally conscious, both the CFL and the LED bulbs are well suited alternatives. Over the long term an LED style bulb will save you the most money although the initial cost may seem high. The good news is that LED bulbs last for 10 years or more. The CFL bulb will save you nearly as much as an LED style Bulb with a fraction of the investment. Consider the placement and how you will be using each of your bulbs and a combination of the two alternatives will be rewarding over the long haul, not just in your pocket book but also for the planet.


F If every home in America replaced just one incandescent light bulb with an ENERGY STAR qualified CFL, in one year it would save enough energy to light more than 3 million homes. That would prevent the release of greenhouse gas emissions equal to that of about 800,000 cars. Saving electricity reduces CO2 emissions, sulfur oxide and high-level nuclear waste.