When you start your search for more efficient lighting products for your home, please do not just go to the store and grab a package of compact florescent light bulbs (CFLs). You may not choose the best bulbs for the application and then think that all CFLs produce poor quality light.
Here is how I choose lightbulbs for my home (a brief description of each item is given here with a more in depth look at each below):
1) Application/Design: This should be the starting place of your search, because it will determine the type (CFL, LED, halogen, tube fluorescent, but we’ll just discuss CFls in this article) physical size and shape of bulb that you need to buy. Also consider whether or not it needs to dim, be in a 3-Way fixture, sparkle, be on a timer or some other special consideration.
2) Color Temperature: This is how “warm” or “cold” a light looks. The lower the color temperature the more orange a light is. Standard incandescent bulbs are 2700 – 3000 K. Daylight and full spectrum bulbs (even incandescent ones) have color temperatures above 4000 K. CFL bulbs range from 2700 K to 6500 K so you need to find the right color before you buy.
3) Light Output: This is measured in lumens, which is the perceived power of a light source. The higher the number of lumens, the greater the light output.
4) Power Draw: Electric power is measured in Watts and you are charged for kilo-Watt-hours (kWh) on your electric bill. This is equivalent to drawing 1,000 Watts of power for one hour.
5) Color Rendering Index (CRI): Is the ability of a light source to accurately reproduce colors. The closer to 100, the more accurate the color reproduction. For 95% of my fixtures, I don’t worry about this number, since I just want general lighting. But for the track lights I use to spotlight some artwork on the wall, this number was right up at the top of the list.
6) Bulb Efficiency: This is a calculation I do to see how many lumens are being output per Watt of power draw. The equation is Efficiency = # of Lumens ¸ Watts.
Once I have the application picked out, this usually quickly defines how much lighting and at what color temperature the light needs to be. Let’s say I am looking to replace the incandescent bulbs in the 5” recessed cans in my kitchen ceiling. Each reflector type bulb draws 100 Watts (W) of power and produces about 950 lumens at 3600 K. The bulbs I chose were Energy Star qualified, the same size and type, reflector type R40 CFL, but these bulbs only drew 26 W of power while producing 1300 lumens of light at 2700 K. My new bulbs were quite a bit brighter, which made up for the more yellow light (a whiter light appears brighter to the human eye), they also reduced power consumption by 74%! I replaced bulbs with an efficiency of 9.5 Lumens per Watt with ones that are at 50.
With replacing the bulbs in the 6 can lights, I had to spend just under $50 to buy and ship them to my house, which seems like a lot when I could buy the same six incandescent bulbs that I had before for just a few dollars. But using CarbonContest’s energy savings calculator I figured out that my new bulbs would save me nearly $41 each year, giving me an annual percentage yield (APY, just like at your bank) of 82%, quite a bit better than the savings account the money was sitting in before.
