According to the stats on your light as found by @LeStat in your other inquiry,
So you have maybe just 10 watts less per light than the total light described above. So if 660 watts cost them about $35 more a month on their electric bill, and if your utility charges about the same rate, then your cost might be double that, right?
650 watts x 2 lights=1300 watts
calley had:
660 watts equaling about $35 a month on the 12 hours on per day schedule.
$35x2=$70, so all thing being equal, your bill would probably be about $70 more a month running your light 12 hours per day. Make sense?
~MacG