PV Gap

Alvin Said:

How long will it take until a solar system is paid off?

We Answered:

Part of the question depends on whether you also use and need the excess heat that this solar array will generate. If you can use the heat, it can be worth about 40% of the value of the electricity.

But if you manage to simply supply the power you now use, your $41.34 per month we come close to 500 per year, with about 29 years to pay off your system. You might have close to double that amount of power to account for, so you might be tempted to think it would pay for itself in perhaps 16 years. I would be inclined to use 20 years, ignoring interest cost. By the time you add in interest cost I think we would be back into 29 year territory.

Because the performance of those systems starts to degrade about 20 years out you have to make allowance for lower sales after 20 years, and the need to replace some panels. Count on about 30 years of life at your original rate of output.

If you can get a Nanosolar system, your system may repay itself in 1/3 of the time. We do not have a long enough history with them to discuss how long they will last.