The worst cast scenario for the new lamp post is it running from 5pm to 7am whitch is 14 hours. Based on my current power generation numbers, a 60 watt bulb costs me $1.25 to run for 14 hours. I switched to an outdoor 13 watt CFL bulb today and now it costs me $0.27 to run for 14 hours. I save $0.98 a night. The bulb cost me $3.97 so after about 4 nights I will already be saving money. Jackpot!