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Before you accept a solar quote

Solar quote & payback calculator

Compare the full installed price with the electricity it could save you. See what changes when exported power earns less or the system produces less than expected.

For a cash purchase of rooftop solar without a battery. No account needed. Your entries stay in this browser. Why cheap panels do not mean a cheap installation.

Your quote and electricity

Use your own figures or load the labeled example. Any prefilled assumptions remain yours to check.

Enter your quote to begin.

Before incentives. Include the complete PV installation; exclude batteries and financing.
Panel nameplate capacity. 8,000 watts = 8 kW. Do not enter the inverter’s AC rating.
Annual AC electricity from the proposal or PVWatts, accounting for system losses.
Share of solar production consumed directly, not share of your annual bill. 50% is an example assumption; try a range.
Variable supply and delivery charges avoided by self-use. Exclude unchanged fixed fees.
Effective value of excess energy after tariff limits or expired credits. Enter 0 if it has no usable value.
Incentives and ongoing costs
Only amounts confirmed for this installation. No automatic federal credit. Delayed payments are treated as upfront here.
Illustrative $100; replace with your estimate for maintenance, repairs and added insurance.
Additional utility fees caused by adding solar. Exclude existing fees that stay the same.
Illustrative 0.5%; use a performance assumption supported by the proposed equipment. Used only in the 25-year scenario.

For new 2026 installations, the former homeowner 30% federal credit is not assumed. Check the IRS rules.

What you will learn

Check the installed price per watt, separate savings from export credits, and test the assumptions behind payback.

A calculation will appear here after you enter a quote or load the example and compare it.

How the calculator works

Installed dollars per watt = cash price ÷ (DC kW × 1,000). Self-used kWh = annual generation × self-use percentage. The remaining generation is exported. First-year net benefit = self-used kWh × avoided purchase price + exported kWh × usable export credit − annual upkeep − extra solar charges.

Simple payback = price after confirmed incentives ÷ first-year net benefit. When net benefit is zero or negative, there is no positive operating benefit to repay the cost. The 25-year scenario applies your output decline each year, starting in year two, and subtracts the same annual expenses each year. Recovery timing is interpolated within a year.

Where to get the inputs

Request the complete cash quote and DC system size from the installer. Obtain a year-one AC production estimate using the proposed layout or PVWatts. Get the export rules and avoidable purchase charges from your utility. PVWatts estimates production; it does not establish your self-use share or validate our payback model.

What if I have net metering, a battery or a loan?

For full-value net metering, enter the same purchase and export rate only when the exported credits are actually usable at that value. This annual model cannot apply monthly credit limits, minimum bills, tiered charges, hourly rates or true-up rules. Use a tariff-specific analysis when those materially affect your bill.

Batteries change the timing of energy use and introduce losses and extra costs. Loans, leases and power purchase agreements have different cash flows. This tool does not evaluate those arrangements. It also does not assess roof condition, shading, electrical design or equipment quality.

Published September 16, 2026. Model: FrugalWatt’s annual screening arithmetic, tested with known examples. Sources reviewed with AI assistance: DOE cost categories, PVWatts production estimator, and IRS homeowner credit rules. No professional assessment or expert review is claimed.