13 cents? I wish. San Diego - I pay .40.
900 watts of cobs cost me under $1300 to build, including frames. And I was able to eliminate the 8 inch fan that was pulling air off the hoods, which means the total reduction was about 400 watts. I'm still hitting the exact same numbers I was before. Also keep in mind that this is a south facing garage with multiple flowering rooms that gets hot af in the afternoons - any reduction in heat is a blessing. Add in yearly bulb change outs to the equation too.
Head space was another consideration for switching to cobs. Half of my garage has lower ceilings - my house is built into a hill. I can only fit tents, and the girls were getting close to the hoods. In my other flowering rooms, they have taller ceilings with framed in rooms, so I run SEs, DEs, and 315s.
I was also able to shave another 200 watts off my 18/6 room by switching out the T5s with PCBs. I'm now getting better results in veg using less wattage.
"LEDs currently are not worth their investment, they give the same or less results as HID lights "
^ That's a false statement.