Solar Savings Estimator

Rough-order-of-magnitude estimate of system size, upfront cost, payback period, and 25-year savings — an honest range machine, not a precision quote. Uses NREL-derived state peak-sun-hours and EIA electricity rates. Every output is a range because too many variables (roof orientation, shading, equipment quality, local utility) are unknown until an installer visits.

Data as ofloading... Get 3+ installer quotes before deciding

Federal credit — loading... Loading current status...

Your situation

State Sets defaults for peak sun hours & electricity rate.

Average monthly electric bill ($)

Electricity rate (¢/kWh) Auto-populated from state average; check your actual bill.

Peak sun hours/day Annual state average; auto-populated. Roof orientation & shading can shift this ±20-30%.

System assumptions

Installed cost ($/watt) US residential average pre-incentive. Simple roofs lower, complex higher.

Bill offset target % 100% means fully covering current usage. Consider 80–95% to avoid oversizing.

Incentives

Federal tax credit % Default 0% for 2026+ (IRC §25D terminated). Override if new legislation applies.

Estimated state/utility incentive ($) Rebates, credits, SRECs. Look yours up at DSIREUSA.org.

Long-term assumptions

Rate inflation %/yr

Panel degrade %/yr

0 kW

System Size

—

0 kWh

Annual Production

—

Upfront Cost (After Incentives)

—

Payback Period

— years

—

25-Year Net Savings

—

Ranges shown Low/high account for ±15% production variance (roof orientation, shading, weather years), ±10% install-cost variance, and rate-inflation uncertainty. Actual results can fall outside this range on either end.

Rough estimate based on state averages. Actual production depends on your roof pitch, azimuth (south-facing best), shading (trees, chimneys, neighboring buildings), panel/inverter equipment, local utility net-metering rules, and time-of-use rate structure. Payback assumes constant rate inflation and steady panel degradation — neither is guaranteed. Get multiple professional quotes and verify current federal, state, and utility incentives at IRS.gov and DSIREUSA.org. This is educational, not financial or engineering advice.

What changed for residential solar in 2026

The 30% federal Residential Clean Energy Credit (IRC §25D) that homeowners relied on from 2022–2025 was terminated for property placed in service after December 31, 2025 by the One Big Beautiful Bill Act, signed in 2025. This is a real and material change: a $25,000 system that would have received a $7,500 federal tax credit in December 2025 receives $0 federal credit in January 2026 and later, unless new legislation restores it.

Any tool, calculator, article, or salesperson still quoting a 30% federal credit for a 2026 installation is out of date. Verify at IRS.gov before signing anything.

What still applies in 2026

State tax credits vary widely. New York, Massachusetts, Maryland, South Carolina, and others have their own credits. Check DSIREUSA.org by state.
Utility rebates exist in many service territories, sometimes only for specific equipment or income brackets.
Net metering rules determine what you’re paid for excess production. California’s NEM 3.0, for example, dramatically lowered export credits — changing the payback math even for identical hardware.
SRECs (Solar Renewable Energy Credits) are tradable in some Northeast/Mid-Atlantic states, adding another income stream.

Why this calculator is a range, not a number

Solar is one of the most assumption-laden purchases a homeowner makes. Roof orientation shifts production ±25%. A single mature oak tree on the south side can drop output 30%. Two identical systems in the same ZIP code can differ 20% in annual output due to microclimate alone. Panel quality varies. Inverter reliability varies. Your utility’s net-metering policy can change during the payback period. Rate inflation is not a straight line.

Any calculator that hands you a single confident number is lying to you. Ours doesn’t. Use the range as a sanity check — if an installer’s bid falls wildly outside these ranges, ask why.

Data sources

Peak sun hours: NREL state solar resource maps.
Electricity rates: EIA Electric Power Monthly (state residential averages).
Federal credit status: IRS Residential Clean Energy Credit page.
State/utility incentives: DSIRE database.
Install cost reference: NREL installed cost data.

Related tools

BTU/HVAC Calculator — size heating/cooling before considering solar.
Mortgage Calculator — compare cash vs. financed system payback.
Compound Interest Calculator — what the same money invested elsewhere might earn.

More Free Tools

All Free Tools BTU/HVAC Calc Mortgage Calc Compound Interest Freelance Rate