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
$65,600
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$17,200
After 30% federal ITC
Your savings
Difference
+$48,400
Estimated lifetime advantage
A $150/month electric bill in the US typically needs 21 solar panels (8.2 kW) at national average electricity rates and sun hours — $17,200 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 2.5 kW in Hawaii to 13.9 kW in Washington, and payback spans 3.3–18.7 years.
Start here: National $150/month guide · Solar savings calculator · 2,000 sq ft by state
| Metric | US average ($150/mo bill) |
|---|---|
| Est. monthly usage | ~920 kWh |
| System size | 8.2 kW |
| Panels (400W) | 21 |
| Net cost after ITC | $17,200 |
| Simple payback | 11.0 years |
| 25-year savings | $48,400+ |
Formula: kW = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
| Fastest payback | Slowest payback | |
|---|---|---|
| State | Hawaii | Washington |
| System | 2.5 kW · 7 panels | 13.9 kW · 35 panels |
| After ITC | $5,200 | $29,200 |
| Payback | 3.3 yrs | 18.7 yrs |
High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for $150/month payback.
| State | System | Panels | After ITC | Payback |
|---|---|---|---|---|
| Alabama | 8.5 kW | 22 | $17,800 | 11.4 yrs |
| Alaska | 8.3 kW | 21 | $17,400 | 11.1 yrs |
| Arizona | 7.0 kW | 18 | $14,700 | 9.4 yrs |
| Arkansas | 10.1 kW | 26 | $21,200 | 13.6 yrs |
| California | 3.5 kW | 9 | $7,400 | 4.7 yrs |
| Colorado | 7.7 kW | 20 | $16,200 | 10.3 yrs |
| Connecticut | 5.8 kW | 15 | $12,100 | 7.7 yrs |
| Delaware | 9.0 kW | 23 | $19,000 | 12.1 yrs |
| Florida | 7.8 kW | 20 | $16,400 | 10.5 yrs |
| Georgia | 8.9 kW | 23 | $18,700 | 11.9 yrs |
| Hawaii | 2.5 kW | 7 | $5,200 | 3.3 yrs |
| Idaho | 10.9 kW | 28 | $23,000 | 14.7 yrs |
| Illinois | 8.8 kW | 22 | $18,400 | 11.7 yrs |
| Indiana | 9.5 kW | 24 | $20,000 | 12.8 yrs |
| Iowa | 11.2 kW | 29 | $23,600 | 15.1 yrs |
| Kansas | 9.1 kW | 23 | $19,100 | 12.2 yrs |
| Kentucky | 11.5 kW | 29 | $24,100 | 15.4 yrs |
| Louisiana | 9.8 kW | 25 | $20,500 | 13.1 yrs |
| Maine | 6.4 kW | 16 | $13,400 | 8.5 yrs |
| Maryland | 8.8 kW | 22 | $18,500 | 11.8 yrs |
| Massachusetts | 5.8 kW | 15 | $12,300 | 7.8 yrs |
| Michigan | 8.2 kW | 21 | $17,300 | 11.1 yrs |
| Minnesota | 9.0 kW | 23 | $19,000 | 12.1 yrs |
| Mississippi | 9.5 kW | 24 | $19,900 | 12.7 yrs |
| Missouri | 9.9 kW | 25 | $20,700 | 13.2 yrs |
| Montana | 10.0 kW | 26 | $21,000 | 13.4 yrs |
| Nebraska | 11.0 kW | 28 | $23,100 | 14.7 yrs |
| Nevada | 6.5 kW | 17 | $13,700 | 8.8 yrs |
| New Hampshire | 6.5 kW | 17 | $13,700 | 8.8 yrs |
| New Jersey | 7.8 kW | 20 | $16,300 | 10.4 yrs |
| New Mexico | 6.7 kW | 17 | $14,100 | 9.0 yrs |
| New York | 6.2 kW | 16 | $13,100 | 8.4 yrs |
| North Carolina | 9.0 kW | 23 | $19,000 | 12.1 yrs |
| North Dakota | 12.3 kW | 31 | $25,700 | 16.4 yrs |
| Ohio | 9.6 kW | 24 | $20,100 | 12.8 yrs |
| Oklahoma | 9.9 kW | 25 | $20,700 | 13.2 yrs |
| Oregon | 10.6 kW | 27 | $22,300 | 14.2 yrs |
| Pennsylvania | 8.5 kW | 22 | $17,900 | 11.4 yrs |
| Rhode Island | 5.7 kW | 15 | $11,900 | 7.6 yrs |
| South Carolina | 8.4 kW | 22 | $17,700 | 11.3 yrs |
| South Dakota | 10.5 kW | 27 | $22,100 | 14.1 yrs |
| Tennessee | 9.9 kW | 25 | $20,700 | 13.2 yrs |
| Texas | 7.8 kW | 20 | $16,300 | 10.4 yrs |
| Utah | 9.3 kW | 24 | $19,400 | 12.4 yrs |
| Vermont | 7.2 kW | 18 | $15,100 | 9.6 yrs |
| Virginia | 9.2 kW | 24 | $19,300 | 12.3 yrs |
| Washington | 13.9 kW | 35 | $29,200 | 18.7 yrs |
| West Virginia | 11.5 kW | 29 | $24,300 | 15.5 yrs |
| Wisconsin | 8.2 kW | 21 | $17,200 | 11.0 yrs |
| Wyoming | 10.5 kW | 27 | $22,000 | 14.0 yrs |
Estimates use EIA state rates, NREL sun hours, and 0.82 derate. National methodology.
$150/month maps to roughly 2,000 sq ft in national usage intensity — close to our 2,000 sq ft sizing tier.
| Sizing method | Best when you know… | National guide |
|---|---|---|
| Monthly bill (this page) | Utility bill amount | $150/mo |
| Home sq ft | House size | 2,000 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 $150/month electric bill.
Electricity rates and incentives vary — see data for your state.