You might have already given some thought to powering your home with solar. Solar photovoltaic panels, which convert sunlight directly into electricity, have fallen so far down in cost that it makes economic sense everywhere. That is why large companies have put in a lot of solar, and even the electric utilities have started installing massive solar farms—it simply costs less than antiquated fossil fuels. Like most homeowners, you would like to save money and eviscerate your electric bill, but you are probably cringing a bit at the upfront cost. To get a rough idea of the cost, a 5kW system that would power an average home installed at $3/W would cost about $15,000, while a larger home might need 10kW to offset all of their electricity purchases and cost $30,000. If you want batteries, double the cost (you don’t need batteries as most solar arrays connect to the grid, but if the grid goes down, so does your solar array until it is turned back on.) Paying for all your electricity for the next several decades is an investment, even if you save a lot of money.