Solar power cost estimator
Last reviewed · same model as the payback calculator
Run the estimator → — enter your power bill and state and it returns system size, installed cost at 3.00/W, payback years, and 25-year net. Free, private, runs entirely on your device. The four-step arithmetic it performs is written out below, and the table gives every state's answer for a representative bill before you type anything.
The estimate in four steps
1 — Energy from the bill. annual kWh = monthly bill × 12 ÷ rate. A $150 bill at $0.15/kWh is 12,000 kWh a year.
2 — System size from sun. kW = annual kWh ÷ 365 ÷ (sun hours × 0.8). The performance ratio 0.8 derates for the real world; sun hours run about 3.5 in the Pacific Northwest to about 6.5 in the Southwest.
3 — Cost from size. cost = kW × 1,000 × 3.00. Batteries, if wanted, price separately per kilowatt-hour on the battery cost page.
4 — Payback from both. years = cost ÷ (monthly bill × 12) before any state incentive. None of it includes a federal credit — that ended for systems completed after December 31, 2025 — so the estimate errs honest.
Every state, a representative 150 bill
| State | System | Installed cost | Payback |
|---|---|---|---|
| Hawaii | 2.6 kW | 7,777 | 4.3 yrs |
| California | 3.6 kW | 10,846 | 6.0 yrs |
| Massachusetts | 5.1 kW | 15,411 | 8.6 yrs |
| Connecticut | 5.5 kW | 16,512 | 9.2 yrs |
| Arizona | 6.3 kW | 18,967 | 10.5 yrs |
| New Mexico | 6.3 kW | 18,967 | 10.5 yrs |
| Nevada | 6.4 kW | 19,264 | 10.7 yrs |
| Maine | 6.7 kW | 20,101 | 11.2 yrs |
| New York | 7.1 kW | 21,159 | 11.8 yrs |
| Colorado | 7.5 kW | 22,416 | 12.5 yrs |
| Florida | 7.8 kW | 23,262 | 12.9 yrs |
| Texas | 7.9 kW | 23,709 | 13.2 yrs |
| Maryland | 8.2 kW | 24,462 | 13.6 yrs |
| New Jersey | 8.2 kW | 24,462 | 13.6 yrs |
| Michigan | 8.5 kW | 25,614 | 14.2 yrs |
| South Carolina | 8.7 kW | 26,231 | 14.6 yrs |
| Pennsylvania | 8.8 kW | 26,344 | 14.6 yrs |
| Washington DC | 9.2 kW | 27,520 | 15.3 yrs |
| Georgia | 9.4 kW | 28,105 | 15.6 yrs |
| Illinois | 9.6 kW | 28,896 | 16.1 yrs |
| Ohio | 9.9 kW | 29,636 | 16.5 yrs |
| Virginia | 10.0 kW | 30,021 | 16.7 yrs |
| North Carolina | 10.1 kW | 30,267 | 16.8 yrs |
| Washington | 16.0 kW | 48,034 | 26.7 yrs |
Your bill will differ; that is what the estimator is for. Full per-state detail — incentives, utilities, net-metering posture — is on each state page.
Reading your own number
An estimate is a starting point, not a destination: quote dispersion for the same roof routinely exceeds any state-to-state difference, so collect real bids against the same inputs and compare them on installed cost per watt. If your payback estimate looks long, the levers that move it are usage (efficiency first), rate trajectory, and the size of the array you actually approve — in that order of leverage.
Questions people ask
How do I estimate my solar cost without a site visit?
Four steps: divide your monthly bill by your state's rate to get annual kilowatt-hours; divide those by your state's peak sun hours × 0.8 to get system size in kilowatts; multiply by 1,000 × 3.00 for installed cost; and divide that cost by your annual bill total for rough payback. The estimator on the homepage does all four from two inputs — bill and state — and the state table below shows the answers before you type anything.
How accurate is a bill-based estimate?
Good enough to know which conversation you are in — and not a quote. Usage patterns, roof orientation, shading, and local install pricing move real numbers by tens of percent. Use the estimate to sanity-check installer quotes against the same inputs; a quote wildly below the estimate deserves the same scrutiny as one wildly above.
Why does the same bill cost different amounts by state?
Two levers: sun hours (a cloudy-state array must be physically bigger to make the same kilowatt-hours) and electricity rates (a high-rate state earns more per kilowatt-hour generated, shortening payback). That is why the table below is sorted by payback rather than alphabetically — the spread between the best and worst states for the same bill is years.
Does the estimate include the federal tax credit?
No — correctly. The 30% federal Residential Clean Energy Credit ended for systems whose installation was completed after December 31, 2025, so a system quoted today has no federal credit to include, and any estimate that still nets it out is overstatement by design. State and utility incentives, where they exist, are the only subtractable items, and the state pages carry them.
The estimator's model: performance ratio 0.8, 3.00/W, representative bill 150/month — documented on the methodology page; reviewed by SolarDime editorial.
Data sources and assumptions
- Electricity ratesU.S. EIA · 2026 state averages
- Solar resourceNREL · 2026 state averages
- Federal tax treatmentIRS · Credit ended for installations completed after 31 Dec 2025 (P.L. 119-21)
- Installed costInstalled cost per watt · 2026 estimate, user-editable
State assumptions last reviewed: . Rules can change; verify your utility and state program before signing a contract. Full methodology.