Estimating how long it will take for a solar system to pay you back in energy savings is an important first step in determining how you want to pay for a system, whether that is cash, financing, a lease, etc. Ask your installer to include an ROI estimate on their quote. You can also develop your own or validate theirs with one of the following tools. Please note that most ROI tools take existing incentives into account, so you’ll need to be sure that you can claim the incentive for the numbers to be realistic.
Solar Power Calculator estimates the cost of installing a solar system and the potential ROI based on different financing options.
Solar Estimate Calculator allows you to calculate the cost of solar panels and savings as well as compare solar quotes.
Solar Plano Advocates provides a worksheet that guides you through calculating total installed and net instllaed cost, cost per kWh, and estimated cost savings over 30-40 years.
Also, keep in mind that installing solar on your property increases its value and will likely get you a higher price when you go to sell. A recent study across eight states by the Lawrence Berkeley Lab titled Selling Into the Sun: Price Premium Analysis of a Multi-State Dataset of Solar Homes found that homes with typical PV systems sold for a premium of $15,000. Some estimate that you can sell for up to 3% higher than a comparable property without solar. The National Association of Realtors has a Green Designee certification for realtors who complete training on energy efficiency features, including solar. A realtor with this designation will have training specifically to help buy or sell properties with "green" features.