25-year cost comparison for a $300/month US electric bill.
Without solar
25-year utility cost
$38,500
Rates rise ~3% per year (EIA avg.)
With solar
Net system cost
$10,100
After 30% federal ITC
Your savings
Difference
+$28,400
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 1,200 square foot home in the US typically needs 13 solar panels (4.8 kW) at national average electricity rates and sun hours β $10,100 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 3.3 kW in Arizona to 7.0 kW in Alaska, and payback spans 3.3β18.7 years.
Direct answers for US homeowners β sized for a 1,200 sq ft home.
Nationally, a 1,200 sq ft home (~539 kWh/month) needs about **13 panels** (4.8 kW) at average US rates and sun hours. State totals range from **9** in Arizona to **18** in Alaska.
**Hawaii** leads at **3.3-year** payback (3.6 kW, $7,600 after ITC). **Washington** is slowest at **18.7 years**.
US average net cost is **$10,100** for a **4.8 kW** system ($14,400 gross). State costs range from **$7,600** (Hawaii) to **$14,700** (Alaska).
Yes β same end goal, different starting point. 1,200 sq ft maps to roughly **$100/month** nationally. Use this hub for **home size**; use the [$100/month bill hub](/guides/solar-panels-100-month-bill-by-state/) if you know your utility bill.
See the [national 1,200 sq ft guide](/guides/how-many-solar-panels-1200-sq-ft/) for roof orientation, panel wattage, and calculator walkthrough. Each state link below adds **local rate & sun hours**.
$100/month electric bill by state
System size and payback vary by electricity rate and sun hours β see your state.