Screen a rooftop system against usable roof capacity, current electricity use, target bill offset, installed cost, degradation, and verified incentives.
Change the inputs that matter to your decision. Optional assumptions stay collapsed until you need them.
The tool sizes toward your bill offset without exceeding usable roof capacity.
Defaults use no tax credit. For residential property placed in service after December 31, 2025, the federal Residential Clean Energy Credit is unavailable; enter only incentives you have independently verified.
The target offset calls for an estimated 7.9 kW system, producing about 100% of current annual use in year one.
The usable roof could support about 8.4 kW, so the estimate stops at the smaller target-sized array.
| Gross installed cost | $23,735$3.00/W |
|---|---|
| Entered incentives | −$0User-entered and not eligibility-verified |
| Estimated net cost | $23,735 |
| 25-year bill savings | $69,075$45,341 after modeled net cost |
This is a state-level screening model. Confirm site-specific irradiance, shade, roof geometry, equipment losses, export compensation, installer pricing, and incentives with PVWatts and qualified professionals.
Practical notes about the inputs, assumptions, and result.
The IRS says the Residential Clean Energy Credit is unavailable for property placed in service after December 31, 2025. Enter only an incentive that applies to your project and tax situation.
No. Use this for early sizing and constraint discovery, then use site-specific PVWatts output and a professional roof and shade assessment.
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