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
$109,400
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$28,700
After 30% federal ITC
Your savings
Difference
+$80,700
Estimated lifetime advantage
A $250/month electric bill in the US typically needs 35 solar panels (13.7 kW) at national average electricity rates and sun hours — $28,700 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 4.1 kW in Hawaii to 23.2 kW in Washington, and payback spans 3.3–18.7 years.
Start here: National $250/month guide · Solar savings calculator · 3,000 sq ft by state
| Metric | US average ($250/mo bill) |
|---|---|
| Est. monthly usage | ~1,534 kWh |
| System size | 13.7 kW |
| Panels (400W) | 35 |
| Net cost after ITC | $28,700 |
| Simple payback | 11.0 years |
| 25-year savings | $80,700+ |
Formula: kW = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
| Fastest payback | Slowest payback | |
|---|---|---|
| State | Hawaii | Washington |
| System | 4.1 kW · 11 panels | 23.2 kW · 59 panels |
| After ITC | $8,600 | $48,700 |
| Payback | 3.3 yrs | 18.7 yrs |
High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for $250/month payback.
| State | System | Panels | After ITC | Payback |
|---|---|---|---|---|
| Alabama | 14.1 kW | 36 | $29,600 | 11.4 yrs |
| Alaska | 13.8 kW | 35 | $29,000 | 11.1 yrs |
| Arizona | 11.7 kW | 30 | $24,500 | 9.4 yrs |
| Arkansas | 16.8 kW | 43 | $35,400 | 13.6 yrs |
| California | 5.9 kW | 15 | $12,300 | 4.7 yrs |
| Colorado | 12.8 kW | 33 | $27,000 | 10.3 yrs |
| Connecticut | 9.6 kW | 25 | $20,200 | 7.7 yrs |
| Delaware | 15.1 kW | 38 | $31,600 | 12.1 yrs |
| Florida | 13.0 kW | 33 | $27,400 | 10.5 yrs |
| Georgia | 14.8 kW | 38 | $31,100 | 11.9 yrs |
| Hawaii | 4.1 kW | 11 | $8,600 | 3.3 yrs |
| Idaho | 18.2 kW | 46 | $38,300 | 14.7 yrs |
| Illinois | 14.6 kW | 37 | $30,700 | 11.7 yrs |
| Indiana | 15.9 kW | 40 | $33,400 | 12.8 yrs |
| Iowa | 18.7 kW | 47 | $39,300 | 15.1 yrs |
| Kansas | 15.2 kW | 38 | $31,900 | 12.2 yrs |
| Kentucky | 19.1 kW | 48 | $40,100 | 15.4 yrs |
| Louisiana | 16.3 kW | 41 | $34,200 | 13.1 yrs |
| Maine | 10.6 kW | 27 | $22,300 | 8.5 yrs |
| Maryland | 14.7 kW | 37 | $30,800 | 11.8 yrs |
| Massachusetts | 9.7 kW | 25 | $20,500 | 7.8 yrs |
| Michigan | 13.7 kW | 35 | $28,800 | 11.1 yrs |
| Minnesota | 15.1 kW | 38 | $31,600 | 12.1 yrs |
| Mississippi | 15.8 kW | 40 | $33,200 | 12.7 yrs |
| Missouri | 16.4 kW | 42 | $34,500 | 13.2 yrs |
| Montana | 16.7 kW | 42 | $35,100 | 13.4 yrs |
| Nebraska | 18.3 kW | 46 | $38,500 | 14.7 yrs |
| Nevada | 10.9 kW | 28 | $22,800 | 8.8 yrs |
| New Hampshire | 10.9 kW | 28 | $22,900 | 8.8 yrs |
| New Jersey | 12.9 kW | 33 | $27,200 | 10.4 yrs |
| New Mexico | 11.2 kW | 29 | $23,600 | 9.0 yrs |
| New York | 10.4 kW | 27 | $21,900 | 8.4 yrs |
| North Carolina | 15.1 kW | 38 | $31,600 | 12.1 yrs |
| North Dakota | 20.4 kW | 52 | $42,900 | 16.4 yrs |
| Ohio | 16.0 kW | 40 | $33,500 | 12.8 yrs |
| Oklahoma | 16.4 kW | 42 | $34,500 | 13.2 yrs |
| Oregon | 17.7 kW | 45 | $37,100 | 14.2 yrs |
| Pennsylvania | 14.2 kW | 36 | $29,800 | 11.4 yrs |
| Rhode Island | 9.5 kW | 24 | $19,900 | 7.6 yrs |
| South Carolina | 14.0 kW | 36 | $29,400 | 11.3 yrs |
| South Dakota | 17.5 kW | 44 | $36,900 | 14.1 yrs |
| Tennessee | 16.4 kW | 42 | $34,500 | 13.2 yrs |
| Texas | 13.0 kW | 33 | $27,200 | 10.4 yrs |
| Utah | 15.4 kW | 39 | $32,400 | 12.4 yrs |
| Vermont | 12.0 kW | 30 | $25,200 | 9.6 yrs |
| Virginia | 15.3 kW | 39 | $32,200 | 12.3 yrs |
| Washington | 23.2 kW | 59 | $48,700 | 18.7 yrs |
| West Virginia | 19.2 kW | 49 | $40,400 | 15.5 yrs |
| Wisconsin | 13.6 kW | 35 | $28,600 | 11.0 yrs |
| Wyoming | 17.4 kW | 44 | $36,600 | 14.0 yrs |
Estimates use EIA state rates, NREL sun hours, and 0.82 derate. National methodology.
$250/month maps to roughly 3,000 sq ft in national usage intensity — close to our 3,000 sq ft sizing tier.
| Sizing method | Best when you know… | National guide |
|---|---|---|
| Monthly bill (this page) | Utility bill amount | $250/mo |
| Home sq ft | House size | 3,000 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 $250/month electric bill.
Electricity rates and incentives vary — see data for your state.