What's the cost

[Ohm1]

Electricity cost 13 cents per kikowatt hour. Ten metal Halide high bay lights draw 2 amps ea at 240 volts for 12 hours a day 5 days a week. How much will these lights cost in a four week period?

[Roger]

2 amps x 10 lights = 20 amps total load. 20 amps x 240 volts = 4800 watts. 4800 watts/1000 = 4.8 kilowatts 60hrs per week x 4 weeks = 240 hours. 240 hrs x 4.8 kilowatts = 1152 kilowatt hrs. 1152 kw hrs x $.13/kw hr = $149.76

[mdshunk]

On a side note, I did a $60,000 job a few years ago in which metal halide high bays were replaced with T5 (yes, T five) fluorescent high bays. They were changed for energy cost savings. The payback on that install was 6 years.

.13 cents/kwh sounds way high to me. Is that right?

[Ohm1]

Good Job Roger:

The answer is $150
(10 luminaires x 2 amps x 240 volts)/ 1000=4.8 KW; (5 days/ weekx 4 weeks x 12 hours/day)=240 hours; (4.8KWx240 hours)=1152 KWH; (1152 KWHx .13 $/KWH)=149.76