I now get 15c per kw and have 5.92 kw installed, total price $6100. I've had 1 system for 4 years paid for itself at 3 years. Other system been on roof for about 10 months. We use most of our generated power but the 15c is welcome now.
As for mine never washed them and their efficiency hasn't suffered one bit. Rain does that job
Rooftop solar is a no brainer if you have a suitable unshaded roof.
I know people on good FITs who paid well over $10k for their systems the roi is just as good if not better for current cheaper systems on net metering.
