US residential solar · 2026 data

4,000 sq ft Home — Solar Guide for All 50 States

Q: "How many solar panels does a 4,000 sq ft house need?"

"Nationally, a 4,000 sq ft home (~1,978 kWh/month) needs about **45 panels** (17.6 kW) at average US rates and sun hours. State totals range from **31** in Arizona to **64** in Alaska."

Q: "Which state has the fastest solar payback for 4,000 sq ft?"

"**Hawaii** leads at **3.3-year** payback (13.2 kW, $27,800 after ITC). **Washington** is slowest at **18.7 years**."

Q: "What does solar cost for a 4,000 sq ft home after the 30% tax credit?"

"US average net cost is **$37,000** for a **17.6 kW** system ($52,900 gross). State costs range from **$27,800** (Hawaii) to **$53,700** (Alaska)."

Q: "Is a 4,000 sq ft sizing guide different from a monthly bill guide?"

"Yes — same end goal, different starting point. 4,000 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 4,000 sq ft methodology?"

"See the [national 4,000 sq ft guide](/guides/how-many-solar-panels-4000-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

$37,000 Cost after ITC

11.0 yrs Payback

17.6 kW Typical system

Most homeowners need:

43–48 panels nationally
17.6 kW average system
$37,000 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 4,000 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

$141,000

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

With solar

Net system cost

$37,000

After 30% federal ITC

Your savings

Difference

+$104,000

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 4,000 square foot home in the US typically needs 45 solar panels (17.6 kW) at national average electricity rates and sun hours — $37,000 after the 30% ITC with 11.0-year payback. State-by-state, system size ranges from 12.2 kW in Arizona to 25.6 kW in Alaska, and payback spans 3.3–18.7 years.

Start here: National 4,000 sq ft guide · System size calculator · $300/month bill by state

National Snapshot: 4,000 sq ft Solar in 2026

Metric	US average (4,000 sq ft)
Est. monthly usage	~1,978 kWh
System size	17.6 kW
Panels (400W)	45
Net cost after ITC	$37,000
Simple payback	11.0 years
25-year savings	$104,000+

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

Fastest & Slowest Payback States for 4,000 sq ft Homes

	Fastest payback	Slowest payback
State	Hawaii	Washington
System	13.2 kW · 34 panels	19.8 kW · 50 panels
After ITC	$27,800	$41,600
Payback	3.3 yrs	18.7 yrs

High electricity rates (e.g. Hawaii, California, Massachusetts) often beat sunny low-rate states for 4,000 sq ft payback.

4,000 sq ft Home — Solar by State (2026)

State	System	Panels	After ITC	Payback
Alabama	15.0 kW	38	$31,400	11.4 yrs
Alaska	25.6 kW	64	$53,700	11.1 yrs
Arizona	12.2 kW	31	$25,600	9.4 yrs
Arkansas	15.9 kW	40	$33,300	13.6 yrs
California	13.7 kW	35	$28,700	4.7 yrs
Colorado	14.4 kW	37	$30,300	10.3 yrs
Connecticut	18.9 kW	48	$39,600	7.7 yrs
Delaware	17.6 kW	45	$37,000	12.1 yrs
Florida	13.9 kW	35	$29,200	10.5 yrs
Georgia	15.2 kW	39	$32,000	11.9 yrs
Hawaii	13.2 kW	34	$27,800	3.3 yrs
Idaho	15.9 kW	40	$33,300	14.7 yrs
Illinois	18.0 kW	46	$37,800	11.7 yrs
Indiana	17.6 kW	45	$37,000	12.8 yrs
Iowa	17.6 kW	45	$37,000	15.1 yrs
Kansas	15.9 kW	40	$33,300	12.2 yrs
Kentucky	17.2 kW	44	$36,200	15.4 yrs
Louisiana	14.7 kW	37	$30,800	13.1 yrs
Maine	18.4 kW	47	$38,700	8.5 yrs
Maryland	17.6 kW	45	$37,000	11.8 yrs
Massachusetts	18.9 kW	48	$39,600	7.8 yrs
Michigan	19.3 kW	49	$40,600	11.1 yrs
Minnesota	17.6 kW	45	$37,000	12.1 yrs
Mississippi	15.2 kW	39	$32,000	12.7 yrs
Missouri	16.5 kW	42	$34,700	13.2 yrs
Montana	16.5 kW	42	$34,700	13.4 yrs
Nebraska	16.5 kW	42	$34,700	14.7 yrs
Nevada	12.4 kW	31	$26,000	8.8 yrs
New Hampshire	18.9 kW	48	$39,600	8.8 yrs
New Jersey	18.0 kW	46	$37,800	10.4 yrs
New Mexico	12.8 kW	32	$26,900	9.0 yrs
New York	18.4 kW	47	$38,700	8.4 yrs
North Carolina	15.2 kW	39	$32,000	12.1 yrs
North Dakota	17.6 kW	45	$37,000	16.4 yrs
Ohio	18.4 kW	47	$38,700	12.8 yrs
Oklahoma	15.0 kW	38	$31,400	13.2 yrs
Oregon	17.6 kW	45	$37,000	14.2 yrs
Pennsylvania	18.9 kW	48	$39,600	11.4 yrs
Rhode Island	18.4 kW	47	$38,700	7.6 yrs
South Carolina	15.0 kW	38	$31,400	11.3 yrs
South Dakota	16.5 kW	42	$34,700	14.1 yrs
Tennessee	15.9 kW	40	$33,300	13.2 yrs
Texas	14.2 kW	36	$29,700	10.4 yrs
Utah	13.7 kW	35	$28,700	12.4 yrs
Vermont	19.3 kW	49	$40,600	9.6 yrs
Virginia	16.9 kW	43	$35,400	12.3 yrs
Washington	19.8 kW	50	$41,600	18.7 yrs
West Virginia	18.9 kW	48	$39,600	15.5 yrs
Wisconsin	18.4 kW	47	$38,700	11.0 yrs
Wyoming	15.9 kW	40	$33,300	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

4,000 sq ft maps to roughly $322/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	4,000 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 4,000 sq ft home.

How many solar panels does a 4,000 sq ft house need?

Nationally, a 4,000 sq ft home (~1,978 kWh/month) needs about **45 panels** (17.6 kW) at average US rates and sun hours. State totals range from **31** in Arizona to **64** in Alaska.

Which state has the fastest solar payback for 4,000 sq ft?

What does solar cost for a 4,000 sq ft home after the 30% tax credit?

Is a 4,000 sq ft sizing guide different from a monthly bill guide?

Where can I read the full national 4,000 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.