Here is a story from Australia about the cost and income from installation of a rooftop photovoltaic electric generation system. It appears that the system would not be economical without heavy government subsidy. The owner appears to think that the government should pay for all of the electricity produced, not just the excess power fed into the electric grid. According to her analysis it would take 8 to 10 years for payback even with the government paying for all power produced, even considering the government's subsidy of the original installation price. For people in North Texas insurance would be another consideration: roofs get destroyed by hail here every few years, and the hail would surely destroy the solar cell array.