How many years until a solar system pays for itself?

Payback is the moment your accumulated savings equal what you paid for the system. For a well-designed residential installation it typically lands in the single-digit years, after which the electricity is effectively free for the rest of the system's life.

What shortens payback

• Higher electricity prices, which make each self-consumed kilowatt-hour worth more
• High self-consumption, so you use what you produce
• A well-sized system, neither too small to matter nor too large to export cheaply
• Any available grant or green financing

What to be careful about

Be wary of anyone promising a guaranteed payback figure without looking at your bills. Payback is a range that depends on your consumption, your tariff and the quality of the install. A serious contractor gives you an estimate grounded in your real data, and explains the assumptions behind it.

Remember the panels keep producing long after payback. Quality modules carry long performance warranties, so the years after break-even are the point of the investment.