We started to think about installing solar on our roof. We have a ~45'x25' south-east-facing roof plane at about 30 degrees inclination, seems to be good enough for an average size installation. Can somebody recommend any installers? What are approximate installation costs we should be expecting (ballpark)? Theoretically, we should expect about 2.4 kWh/sq.m/day at this plane (given 3.55 kWh/sq.m/day at latitude tilt according to this map http://www.nrel.gov/gis/images/map_pv_national_hi-res_200.jpg). Assuming 15% efficiency of the panels, we hope to be looking at about 35-40 kWh/day on average. Are those realistic numbers? BTW, looks like we're in the worst part of the lower 48 solar-wise. AZ and NM get almost twice the amount of energy we get.