Compact fluorescent lamps (CFLs) have become a popular choice among energy-conscious homeowners. CFLs consume as little as one-fifth the power and last up to 13 times longer than incandescent lamps. A single CFL can save enough electricity (coal-fired) to keep a ton of carbon dioxide out of the atmosphere¹.

While CFLs may save a lot of energy, some people comment that they are not as bright as they would like when they first turn them on. We decided to put some bulbs to the test to see how long it takes for various CFLs to reach maximum brightness, using our Light Sensor. We tested a 14 W GE Soft White 60 Energy Saving Bulb, a 14 W Lights of America® Mini Twister, and a 20 W IKEA^® bulb.

We found that the Lights of America CFL took about 100 seconds to reach maximum brightness, and it stayed at that brightness for the remainder of the experiment. The GE Soft White CFL took about 360 seconds to reach maximum brightness. The IKEA light settled in at its operating brightness at about 470 seconds, after reaching a maximum, and then decreasing to its operating brightness.

¹Compact Fluorescent Lamps: What You Should Know, D.W. Finn and M.J. Ouellette, http://irc.nrc-cnrc.gc.ca/practice/lig3_E.html