you may be interested to know that the price of solar panels has dropped by half in the last year and a factor of 24 over the last 15; see my summary at https://news.ycombinator.com/item?id=39544358
Holy shite. I had been putting this off cause 45k (when I initially looked) was a pretty tough pill to swallow. We’re down to 15k installed around here (which I suspect is pretty close to the floor, everything else will be profits for installation as years go on).
it's close to the floor because the installers are structured for the economic structure they had when it was 45k. you'll see new approaches that make different tradeoffs to reflect the new, lower panel prices
for example, inverters: if your solar installation costs 2 dollars a watt all told, it makes sense to spend an extra hundred bucks on a more efficient inverter if it squeezes 300 more watts out of the panels, but not if the solar installation costs 20 cents a watt. (and maybe you can run some 24-volt dc wiring instead of stepping it up to 120—or put together a constant-current system instead of a constant-voltage one, so the voltage drop in the wires doesn't have to stay within a narrow tolerance.)
or packaging: the glass now costs significantly more than the cells do, and the frames are expensive too—could you make do by gluing the cells to thin polycarbonate, like a compact disc, instead of to glass? even if it cut into longevity
and maybe you can do a rooftop installation of a lightweight installation with a long pole with a hook on the end, or something, instead of having a guy climb up on the roof with a ladder—potentially falling off and dying, which is both a human tragedy and an insurance cost
or hang the cells vertically under the eaves on the east or west side of the house, like wind chimes: no midday sun, and a significantly diminished capacity factor when you do get sun, but also no holes drilled in the roof, no rigid frames, no rain, and no hailstones