Reply #22: The math is interesting

[LondonReign2]

The average US home in 2006 used 920 kWh/month.

It is difficult to use an average in terms of efficiency since different parts of the US get very different amound of sunlight, but the price to install solar is roughly $5-$7 per kWh.

So a fully installed system covering average usage (setting aside for now the incremental cost for plugging in yor car) would cost between $55,000 and $77,000, with a life expectency of 12-20 years.

Those numbers assume solar panels that are 12%-14% efficient. SunTech Power, one of the many Chinese solar companies, is opening a new plant that they say produces panels with 20% efficiency. That increase in efficiency would certainly help the price point for rolling solar out on a large-scale basis.