Solar Payback Calculator 2026

Our payback calculator uses real installation pricing from NuWatt projects across nine states, combined with current EIA utility rate data and verified state incentive programs. Here is exactly how each number is calculated:

The volume discount of 4% applies to systems of 8 kW and above, reflecting the economies of scale in larger installations. State adders account for permitting complexity, labor market differences, and interconnection requirements that vary by jurisdiction.

Production factors are based on NREL PVWatts data for each state, assuming standard module type, fixed roof-mount, and typical inverter efficiency. South-facing roofs produce the most energy, while east and west orientations lose roughly 15%. Flat roofs (common on commercial buildings and some modern homes) assume a 10-degree tilt and produce about 90% of optimal output.

Year 1 savings are capped at your actual electric bill because most net metering programs do not pay you for excess production beyond your usage. The 25-year projection uses a geometric series to account for compounding utility rate increases, which have historically averaged 3-5% annually in the Northeast.

This is the single biggest change to solar economics in a decade. For an 8 kW system costing $26,000, homeowners previously received roughly $7,800 back from the IRS. That money now stays on the table, extending payback periods by 2-3 years in most states.

However, the commercial Investment Tax Credit (ITC) under Sections 48 and 48E remains intact. This means third-party owned residential systems -- solar leases and power purchase agreements (PPAs) -- still benefit from the 30% credit. The solar company claims the credit and passes the savings to you through lower monthly payments. For homeowners who cannot or prefer not to pay cash, this makes leases and PPAs significantly more attractive in 2026 than they were when the residential credit existed.

State incentives have also become the primary driver of solar economics. States like New Jersey, Massachusetts, and Connecticut offer substantial programs that can reduce net costs by $10,000-$15,000, cutting payback periods nearly in half compared to states with no incentive programs.

With the federal credit gone, state incentives are the only financial boost available for homeowner-owned solar. Here is what each state in our service area offers:

Incentive values are estimates for a typical 8 kW residential system and may vary based on system size, installer, and program availability. SREC and REC values fluctuate with market conditions. Last updated February 2026.