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
$218,800
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$57,400
After 30% federal ITC
Your savings
Difference
+$161,400
Estimated lifetime advantage
A $500/month electric bill in the US typically needs 69 solar panels (27.3 kW) at national average electricity rates and sun hours — $57,400 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 8.2 kW in Hawaii to 46.4 kW in Washington, and payback spans 3.3–18.7 years.
Start here: National $500/month guide · Solar savings calculator · 3,500 sq ft by state
| Metric | US average ($500/mo bill) |
|---|---|
| Est. monthly usage | ~3,067 kWh |
| System size | 27.3 kW |
| Panels (400W) | 69 |
| Net cost after ITC | $57,400 |
| Simple payback | 11.0 years |
| 25-year savings | $161,400+ |
Formula: kW = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
| Fastest payback | Slowest payback | |
|---|---|---|
| State | Hawaii | Washington |
| System | 8.2 kW · 21 panels | 46.4 kW · 117 panels |
| After ITC | $17,200 | $97,400 |
| Payback | 3.3 yrs | 18.7 yrs |
High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for $500/month payback.
| State | System | Panels | After ITC | Payback |
|---|---|---|---|---|
| Alabama | 28.2 kW | 71 | $59,300 | 11.4 yrs |
| Alaska | 27.6 kW | 70 | $58,000 | 11.1 yrs |
| Arizona | 23.4 kW | 59 | $49,100 | 9.4 yrs |
| Arkansas | 33.7 kW | 85 | $70,800 | 13.6 yrs |
| California | 11.8 kW | 30 | $24,700 | 4.7 yrs |
| Colorado | 25.7 kW | 65 | $53,900 | 10.3 yrs |
| Connecticut | 19.2 kW | 49 | $40,400 | 7.7 yrs |
| Delaware | 30.1 kW | 76 | $63,200 | 12.1 yrs |
| Florida | 26.1 kW | 66 | $54,700 | 10.5 yrs |
| Georgia | 29.7 kW | 75 | $62,300 | 11.9 yrs |
| Hawaii | 8.2 kW | 21 | $17,200 | 3.3 yrs |
| Idaho | 36.4 kW | 92 | $76,500 | 14.7 yrs |
| Illinois | 29.2 kW | 74 | $61,300 | 11.7 yrs |
| Indiana | 31.8 kW | 80 | $66,800 | 12.8 yrs |
| Iowa | 37.4 kW | 94 | $78,600 | 15.1 yrs |
| Kansas | 30.4 kW | 76 | $63,800 | 12.2 yrs |
| Kentucky | 38.2 kW | 96 | $80,300 | 15.4 yrs |
| Louisiana | 32.6 kW | 82 | $68,400 | 13.1 yrs |
| Maine | 21.2 kW | 53 | $44,500 | 8.5 yrs |
| Maryland | 29.3 kW | 74 | $61,500 | 11.8 yrs |
| Massachusetts | 19.5 kW | 49 | $40,900 | 7.8 yrs |
| Michigan | 27.5 kW | 69 | $57,700 | 11.1 yrs |
| Minnesota | 30.1 kW | 76 | $63,200 | 12.1 yrs |
| Mississippi | 31.6 kW | 79 | $66,400 | 12.7 yrs |
| Missouri | 32.9 kW | 83 | $69,100 | 13.2 yrs |
| Montana | 33.4 kW | 84 | $70,200 | 13.4 yrs |
| Nebraska | 36.6 kW | 92 | $76,900 | 14.7 yrs |
| Nevada | 21.8 kW | 55 | $45,700 | 8.8 yrs |
| New Hampshire | 21.8 kW | 55 | $45,800 | 8.8 yrs |
| New Jersey | 25.9 kW | 65 | $54,400 | 10.4 yrs |
| New Mexico | 22.5 kW | 57 | $47,200 | 9.0 yrs |
| New York | 20.8 kW | 53 | $43,700 | 8.4 yrs |
| North Carolina | 30.1 kW | 76 | $63,200 | 12.1 yrs |
| North Dakota | 40.9 kW | 103 | $85,800 | 16.4 yrs |
| Ohio | 31.9 kW | 80 | $67,100 | 12.8 yrs |
| Oklahoma | 32.9 kW | 83 | $69,100 | 13.2 yrs |
| Oregon | 35.4 kW | 89 | $74,200 | 14.2 yrs |
| Pennsylvania | 28.4 kW | 72 | $59,700 | 11.4 yrs |
| Rhode Island | 19.0 kW | 48 | $39,800 | 7.6 yrs |
| South Carolina | 28.0 kW | 71 | $58,800 | 11.3 yrs |
| South Dakota | 35.1 kW | 88 | $73,700 | 14.1 yrs |
| Tennessee | 32.9 kW | 83 | $69,000 | 13.2 yrs |
| Texas | 25.9 kW | 65 | $54,500 | 10.4 yrs |
| Utah | 30.9 kW | 78 | $64,800 | 12.4 yrs |
| Vermont | 24.0 kW | 60 | $50,300 | 9.6 yrs |
| Virginia | 30.7 kW | 77 | $64,400 | 12.3 yrs |
| Washington | 46.4 kW | 117 | $97,400 | 18.7 yrs |
| West Virginia | 38.5 kW | 97 | $80,800 | 15.5 yrs |
| Wisconsin | 27.3 kW | 69 | $57,300 | 11.0 yrs |
| Wyoming | 34.9 kW | 88 | $73,200 | 14.0 yrs |
Estimates use EIA state rates, NREL sun hours, and 0.82 derate. National methodology.
$500/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 | $500/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 $500/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.