Estimating Solar Costs and Simple Payback
Updated September 22, 2026
Start with a complete quote
Include equipment, wiring, protection devices, mounting, permits, labor and any electrical upgrades. Subtract only incentives confirmed for your project.
Estimate annual net savings
For a grid-connected system, compare the electricity bill with and without solar using your utility's actual rates and export rules. Include ongoing maintenance. A battery does not generate electricity and may need replacement during the life of the array.
A simple example, not a forecast
If a project costs $15,000 after confirmed incentives and saves $1,000 per year after routine operating costs, its simple payback is 15 years. This example excludes financing, changes in rates, equipment degradation and major replacements. Different inputs produce different outcomes.
Off-grid projects need a different comparison
Compare the cost of solar and storage with the realistic alternative: a grid extension, generator fuel and maintenance, or reduced electricity use. Do not count utility-bill savings if there was no utility connection to begin with.
Federal residential clean energy credit
The IRS states that the Residential Clean Energy Credit (Section 25D) is not available for property placed in service after December 31, 2025. Do not assume that a new 2026 residential solar or battery installation receives a 30% federal credit.
For eligible earlier installations, consult the IRS instructions for the relevant tax year and any carryforward rules. Business-owned projects follow separate rules and require a project-specific review.
Source: IRS Residential Clean Energy Credit.