Q You recently answered a question about how much it would cost to burn a bulb in a hallway 24 hours a day, seven days a week. I think you missed an opportunity to compare that cost to an energy-efficient bulb. So, if that light has to remain on, how much would you save if the bulb were a compact fluorescent (CFL) as opposed to a traditional incandescent?
A Energy specialist Phil Smith, at the Minnesota Department of Energy Security offered the following assessment:
The annual cost of operating a 60-watt incandescent light bulb is $47.30.
The annual cost of operating a 15-watt CFL is $11.86.
But there's more to it than that.
A 60-watt bulb has a life expectancy of 1,000 hours.
A 15-watt CFL has a life expectancy of 8,000 to 10,000 hours.
It is reasonable to assume that you'd need eight 60-watt bulbs to light the hall in question 24 hours a day for one year, but you'd only need one CFL for the same time period.
