25-year cost comparison for a $300/month US electric bill.
Without solar
25-year utility cost
$101,000
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$26,500
After 30% federal ITC
Your savings
Difference
+$74,500
Estimated lifetime advantage
500,000+
calculations completed
25,000+
users monthly
Trusted by US homeowners Β· Data sourced from
NRELEIAEnergy.govDSIREIRS / SEIA
AuthorMark Sullivan
Reviewed byGreen Energy Calculators Editorial Team
Last updated
Data approachSee data quality and methodology below.
A 3,000 square foot home in the US typically needs 32 solar panels (12.6 kW) at national average electricity rates and sun hours β $26,500 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 8.7 kW in Arizona to 18.3 kW in Alaska, and payback spans 3.3β18.7 years.
Direct answers for US homeowners β sized for a 3,000 sq ft home.
Nationally, a 3,000 sq ft home (~1,416 kWh/month) needs about **32 panels** (12.6 kW) at average US rates and sun hours. State totals range from **22** in Arizona to **46** in Alaska.
**Hawaii** leads at **3.3-year** payback (9.5 kW, $19,900 after ITC). **Washington** is slowest at **18.7 years**.
US average net cost is **$26,500** for a **12.6 kW** system ($37,800 gross). State costs range from **$19,900** (Hawaii) to **$38,500** (Alaska).
Yes β same end goal, different starting point. 3,000 sq ft maps to roughly **$250/month** nationally. Use this hub for **home size**; use the [$250/month bill hub](/guides/solar-panels-250-month-bill-by-state/) if you know your utility bill.
See the [national 3,000 sq ft guide](/guides/how-much-do-solar-panels-cost-3000-sq-ft-home/) for roof orientation, panel wattage, and calculator walkthrough. Each state link below adds **local rate & sun hours**.
$250/month electric bill by state
System size and payback vary by electricity rate and sun hours β see your state.