How much does a light bulb cost to run?

Question

(1 2" fluro for 24 hours?

Answer 1

Does '1 2"' mean one two-inch fluorescent?   Or a 12 inch?   Or do you mean one two-foot fluorescent?

In any case,  just multiply the power level in watts times 24, and that will tell you how many watt-hours are being consumed.    Divide that number by 1000 and then look on your electric bill to see how much you're paying per kilowatt hour (that is, for each 1000 watt-hours).  

So, for example, a 24 inch fluorescent consumes about 20 watts.   20 watts x 24 hours = 480 watt hours.    480/1000 = 0.48 kilowatt hours, or roughly 1/2 of a kW/hr per day.  

If you're paying $0.30 per kilowatt hour, then it would cost about 15 cents a day.