SAVE
$0+
Over 25 Years
Most homeowners need:
25-year cost comparison for a $300/month US electric bill.
Without solar
25-year utility cost
$153,100
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$40,200
After 30% federal ITC
Your savings
Difference
+$113,000
Estimated lifetime advantage
A $350/month electric bill in the US typically needs 48 solar panels (19.1 kW) at national average electricity rates and sun hours — $40,200 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 5.7 kW in Hawaii to 32.5 kW in Washington, and payback spans 3.3–18.7 years.
Start here: National $350/month guide · Solar savings calculator · 3,500 sq ft by state
| Metric | US average ($350/mo bill) |
|---|---|
| Est. monthly usage | ~2,147 kWh |
| System size | 19.1 kW |
| Panels (400W) | 48 |
| Net cost after ITC | $40,200 |
| Simple payback | 11.0 years |
| 25-year savings | $113,000+ |
Formula: kW = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
| Fastest payback | Slowest payback | |
|---|---|---|
| State | Hawaii | Washington |
| System | 5.7 kW · 15 panels | 32.5 kW · 82 panels |
| After ITC | $12,000 | $68,200 |
| Payback | 3.3 yrs | 18.7 yrs |
High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for $350/month payback.
| State | System | Panels | After ITC | Payback |
|---|---|---|---|---|
| Alabama | 19.8 kW | 50 | $41,500 | 11.4 yrs |
| Alaska | 19.3 kW | 49 | $40,600 | 11.1 yrs |
| Arizona | 16.4 kW | 41 | $34,300 | 9.4 yrs |
| Arkansas | 23.6 kW | 59 | $49,500 | 13.6 yrs |
| California | 8.2 kW | 21 | $17,300 | 4.7 yrs |
| Colorado | 18.0 kW | 45 | $37,700 | 10.3 yrs |
| Connecticut | 13.5 kW | 34 | $28,300 | 7.7 yrs |
| Delaware | 21.1 kW | 53 | $44,200 | 12.1 yrs |
| Florida | 18.2 kW | 46 | $38,300 | 10.5 yrs |
| Georgia | 20.8 kW | 52 | $43,600 | 11.9 yrs |
| Hawaii | 5.7 kW | 15 | $12,000 | 3.3 yrs |
| Idaho | 25.5 kW | 64 | $53,600 | 14.7 yrs |
| Illinois | 20.4 kW | 52 | $42,900 | 11.7 yrs |
| Indiana | 22.3 kW | 56 | $46,800 | 12.8 yrs |
| Iowa | 26.2 kW | 66 | $55,000 | 15.1 yrs |
| Kansas | 21.3 kW | 54 | $44,600 | 12.2 yrs |
| Kentucky | 26.8 kW | 67 | $56,200 | 15.4 yrs |
| Louisiana | 22.8 kW | 57 | $47,900 | 13.1 yrs |
| Maine | 14.8 kW | 38 | $31,200 | 8.5 yrs |
| Maryland | 20.5 kW | 52 | $43,100 | 11.8 yrs |
| Massachusetts | 13.6 kW | 35 | $28,600 | 7.8 yrs |
| Michigan | 19.2 kW | 49 | $40,400 | 11.1 yrs |
| Minnesota | 21.1 kW | 53 | $44,200 | 12.1 yrs |
| Mississippi | 22.1 kW | 56 | $46,500 | 12.7 yrs |
| Missouri | 23.0 kW | 58 | $48,300 | 13.2 yrs |
| Montana | 23.4 kW | 59 | $49,100 | 13.4 yrs |
| Nebraska | 25.6 kW | 65 | $53,900 | 14.7 yrs |
| Nevada | 15.2 kW | 39 | $32,000 | 8.8 yrs |
| New Hampshire | 15.3 kW | 39 | $32,000 | 8.8 yrs |
| New Jersey | 18.1 kW | 46 | $38,100 | 10.4 yrs |
| New Mexico | 15.7 kW | 40 | $33,000 | 9.0 yrs |
| New York | 14.6 kW | 37 | $30,600 | 8.4 yrs |
| North Carolina | 21.1 kW | 53 | $44,300 | 12.1 yrs |
| North Dakota | 28.6 kW | 72 | $60,100 | 16.4 yrs |
| Ohio | 22.4 kW | 56 | $46,900 | 12.8 yrs |
| Oklahoma | 23.0 kW | 58 | $48,300 | 13.2 yrs |
| Oregon | 24.7 kW | 62 | $52,000 | 14.2 yrs |
| Pennsylvania | 19.9 kW | 50 | $41,800 | 11.4 yrs |
| Rhode Island | 13.3 kW | 34 | $27,900 | 7.6 yrs |
| South Carolina | 19.6 kW | 50 | $41,200 | 11.3 yrs |
| South Dakota | 24.6 kW | 62 | $51,600 | 14.1 yrs |
| Tennessee | 23.0 kW | 58 | $48,300 | 13.2 yrs |
| Texas | 18.2 kW | 46 | $38,100 | 10.4 yrs |
| Utah | 21.6 kW | 55 | $45,400 | 12.4 yrs |
| Vermont | 16.8 kW | 42 | $35,200 | 9.6 yrs |
| Virginia | 21.5 kW | 54 | $45,100 | 12.3 yrs |
| Washington | 32.5 kW | 82 | $68,200 | 18.7 yrs |
| West Virginia | 26.9 kW | 68 | $56,600 | 15.5 yrs |
| Wisconsin | 19.1 kW | 48 | $40,100 | 11.0 yrs |
| Wyoming | 24.4 kW | 62 | $51,300 | 14.0 yrs |
Estimates use EIA state rates, NREL sun hours, and 0.82 derate. National methodology.
$350/month maps to roughly 3,500 sq ft in national usage intensity — close to our 3,500 sq ft sizing tier.
| Sizing method | Best when you know… | National guide |
|---|---|---|
| Monthly bill (this page) | Utility bill amount | $350/mo |
| Home sq ft | House size | 3,500 sq ft |
Use both: if your bill differs from the sq ft estimate, trust your kWh usage from the utility statement.
Direct answers for US homeowners — sized for a $350/month electric bill.
Electricity rates and incentives vary — see data for your state.
Solar rules and net metering vary by utility — not just by state.
Calculation method: System size uses NREL PVWatts derate factor (0.82). Costs based on SEIA 2026 installed cost ($2.75–$3.20/W). Payback uses net cost after 30% federal ITC (IRC Section 25D). Savings assume full-retail net metering unless noted.
Official sources: EIA state electricity rates · NREL PVWatts · Energy.gov ITC guide · DSIRE incentives · SEIA market data · IRS Publication 5695.
All figures are estimates for educational purposes — not tax, legal, or investment advice. Consult a licensed installer and CPA for your situation.