Note the qualification "after energy costs and tax credits". There's definitely cheaper roofing material (our house has a flat rubber roof--much cheaper than ti

Note the qualification "after energy costs and tax credits". There's definitely cheaper roofing material (our house has a flat rubber roof--much cheaper than tile). Tax credits, of course, vary by jurisdiction, and may not always be available. It would also be useful to compare the cost to more traditional sorts of solar installations.