US residential solar · 2026 data

3,500 sq ft Home — Solar Guide for All 50 States

Q: "How many solar panels does a 3,500 sq ft house need?"

"Nationally, a 3,500 sq ft home (~1,691 kWh/month) needs about **38 panels** (15.1 kW) at average US rates and sun hours. State totals range from **27** in Arizona to **55** in Alaska."

Q: "Which state has the fastest solar payback for 3,500 sq ft?"

"**Hawaii** leads at **3.3-year** payback (11.3 kW, $23,700 after ITC). **Washington** is slowest at **18.7 years**."

Q: "What does solar cost for a 3,500 sq ft home after the 30% tax credit?"

"US average net cost is **$31,600** for a **15.1 kW** system ($45,200 gross). State costs range from **$23,700** (Hawaii) to **$45,900** (Alaska)."

Q: "Is a 3,500 sq ft sizing guide different from a monthly bill guide?"

"Yes — same end goal, different starting point. 3,500 sq ft maps to roughly **$300/month** nationally. Use this hub for **home size**; use the [$300/month bill hub](/guides/solar-panels-300-month-bill-by-state/) if you know your utility bill."

Q: "Where can I read the full national 3,500 sq ft methodology?"

"See the [national 3,500 sq ft guide](/guides/how-many-solar-panels-3500-sq-ft-house/) for roof orientation, panel wattage, and calculator walkthrough. Each state link below adds **local rate \u0026 sun hours**."

SAVE

$0+

Over 25 Years

$31,600 Cost after ITC

11.0 yrs Payback

15.1 kW Typical system

Most homeowners need:

36–41 panels nationally
15.1 kW average system
$31,600 after tax credits
11.0 year national payback

✓ Updated monthly ✓ NREL data ✓ Reviewed by solar experts ✓ IRS tax credit included

Updated June 9, 2026 · 3 min read ·By Mark Sullivan ·Reviewed by Green Energy Calculators Editorial Team

Calculate System Size National 3,500 sq ft Guide

Without solar vs with solar

25-year cost comparison for a $300/month US electric bill.

Without solar

25-year utility cost

$120,600

Rates rise ~3% per year (EIA avg.)

With solar

Net system cost

$31,600

After 30% federal ITC

Your savings

Difference

+$89,000

Estimated lifetime advantage

Author Mark Sullivan

Reviewed by Green Energy Calculators Editorial Team

Last updated Jun 9, 2026

Sizing formula kW = Annual kWh ÷ (Peak Sun Hours × 365 × 0.82)

A 3,500 square foot home in the US typically needs 38 solar panels (15.1 kW) at national average electricity rates and sun hours — $31,600 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 10.4 kW in Arizona to 21.9 kW in Alaska, and payback spans 3.3–18.7 years.

Start here: National 3,500 sq ft guide · System size calculator · $300/month bill by state

National Snapshot: 3,500 sq ft Solar in 2026

Metric	US average (3,500 sq ft)
Est. monthly usage	~1,691 kWh
System size	15.1 kW
Panels (400W)	38
Net cost after ITC	$31,600
Simple payback	11.0 years
25-year savings	$89,000+

Formula: kW = Annual kWh ÷ (Peak sun hours × 365 × 0.82)

Fastest & Slowest Payback States for 3,500 sq ft Homes

	Fastest payback	Slowest payback
State	Hawaii	Washington
System	11.3 kW · 29 panels	17.0 kW · 43 panels
After ITC	$23,700	$35,600
Payback	3.3 yrs	18.7 yrs

High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for 3,500 sq ft payback.

3,500 sq ft Home — Solar by State (2026)

State	System	Panels	After ITC	Payback
Alabama	12.8 kW	32	$26,900	11.4 yrs
Alaska	21.9 kW	55	$45,900	11.1 yrs
Arizona	10.4 kW	27	$21,900	9.4 yrs
Arkansas	13.6 kW	34	$28,500	13.6 yrs
California	11.7 kW	30	$24,600	4.7 yrs
Colorado	12.3 kW	31	$25,900	10.3 yrs
Connecticut	16.1 kW	41	$33,900	7.7 yrs
Delaware	15.1 kW	38	$31,600	12.1 yrs
Florida	11.9 kW	30	$25,000	10.5 yrs
Georgia	13.0 kW	33	$27,400	11.9 yrs
Hawaii	11.3 kW	29	$23,700	3.3 yrs
Idaho	13.6 kW	34	$28,500	14.7 yrs
Illinois	15.4 kW	39	$32,400	11.7 yrs
Indiana	15.1 kW	38	$31,600	12.8 yrs
Iowa	15.1 kW	38	$31,600	15.1 yrs
Kansas	13.6 kW	34	$28,500	12.2 yrs
Kentucky	14.7 kW	37	$31,000	15.4 yrs
Louisiana	12.6 kW	32	$26,400	13.1 yrs
Maine	15.8 kW	40	$33,100	8.5 yrs
Maryland	15.1 kW	38	$31,600	11.8 yrs
Massachusetts	16.1 kW	41	$33,900	7.8 yrs
Michigan	16.5 kW	42	$34,700	11.1 yrs
Minnesota	15.1 kW	38	$31,600	12.1 yrs
Mississippi	13.0 kW	33	$27,400	12.7 yrs
Missouri	14.1 kW	36	$29,700	13.2 yrs
Montana	14.1 kW	36	$29,700	13.4 yrs
Nebraska	14.1 kW	36	$29,700	14.7 yrs
Nevada	10.6 kW	27	$22,200	8.8 yrs
New Hampshire	16.1 kW	41	$33,900	8.8 yrs
New Jersey	15.4 kW	39	$32,400	10.4 yrs
New Mexico	10.9 kW	28	$23,000	9.0 yrs
New York	15.8 kW	40	$33,100	8.4 yrs
North Carolina	13.0 kW	33	$27,400	12.1 yrs
North Dakota	15.1 kW	38	$31,600	16.4 yrs
Ohio	15.8 kW	40	$33,100	12.8 yrs
Oklahoma	12.8 kW	32	$26,900	13.2 yrs
Oregon	15.1 kW	38	$31,600	14.2 yrs
Pennsylvania	16.1 kW	41	$33,900	11.4 yrs
Rhode Island	15.8 kW	40	$33,100	7.6 yrs
South Carolina	12.8 kW	32	$26,900	11.3 yrs
South Dakota	14.1 kW	36	$29,700	14.1 yrs
Tennessee	13.6 kW	34	$28,500	13.2 yrs
Texas	12.1 kW	31	$25,400	10.4 yrs
Utah	11.7 kW	30	$24,600	12.4 yrs
Vermont	16.5 kW	42	$34,700	9.6 yrs
Virginia	14.4 kW	37	$30,300	12.3 yrs
Washington	17.0 kW	43	$35,600	18.7 yrs
West Virginia	16.1 kW	41	$33,900	15.5 yrs
Wisconsin	15.8 kW	40	$33,100	11.0 yrs
Wyoming	13.6 kW	34	$28,500	14.0 yrs

Estimates use EIA state rates, NREL sun hours, and typical kWh/sqft intensity. National methodology.

How Sq Ft Sizing Compares to Monthly Bill Guides

3,500 sq ft maps to roughly $276/month in utility spend nationally — close to our $300/month bill tier.

Sizing method	Best when you know…	National guide
Sq ft (this page)	Home size	3,500 sq ft
Monthly bill	Utility bill amount	$300/mo

Use both: if your actual bill differs from the sq ft estimate, trust your kWh usage from the utility statement.

Frequently asked questions

Direct answers for US homeowners — sized for a 3,500 sq ft home.

How many solar panels does a 3,500 sq ft house need?

Nationally, a 3,500 sq ft home (~1,691 kWh/month) needs about **38 panels** (15.1 kW) at average US rates and sun hours. State totals range from **27** in Arizona to **55** in Alaska.

Which state has the fastest solar payback for 3,500 sq ft?

What does solar cost for a 3,500 sq ft home after the 30% tax credit?

Is a 3,500 sq ft sizing guide different from a monthly bill guide?

Where can I read the full national 3,500 sq ft methodology?

$300/month electric bill by state

System size and payback vary by electricity rate and sun hours — see your state.

CA California $300/mo · 29.4¢/kWh TX Texas $300/mo · 13.8¢/kWh FL Florida $300/mo · 13.5¢/kWh AZ Arizona $300/mo · 13.2¢/kWh NC North Carolina $300/mo · 12.8¢/kWh NY New York $300/mo · 22.4¢/kWh MA Massachusetts $300/mo · 24.5¢/kWh CO Colorado $300/mo · 14.2¢/kWh

Compare all 50 states for $300/mo →

Same usage, bill-based guide

Your target maps to roughly a $300/month electric bill nationally.

$300 $300/month electric bill guide Panels · cost · payback · by state →

Popular utility companies

Solar rules and net metering vary by utility — not just by state.

PG&E California Duke Energy NC · FL · Midwest Florida Power & Light Florida Oncor Texas APS Arizona Georgia Power Georgia

Methodology & data sources

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.