US residential solar · 2026 data

How Many Solar Panels for 1,100 kWh per Month?

Q: How much does a solar system for 1,100 kWh per month cost in 2026?

A roughly 9.2 kW system costs about $23,000–$32,000 before incentives at $2.50–$3.50 per watt installed. Marketplace quotes in early 2026 have averaged near $2.58 per watt, while Lawrence Berkeley National Laboratory reported a 2024 median of about $3.50 per watt for cash purchases. Because soft costs like labor, permitting and overhead make up a large share, quotes for identical equipment can differ by thousands of dollars, so compare at least three.

Q: Is the 30% federal solar tax credit still available in 2026?

No, not for systems you buy with cash or a loan. The homeowner Residential Clean Energy Credit (Section 25D) ended for expenditures after December 31, 2025, under the One Big Beautiful Bill Act. Leased and PPA systems can still benefit from the business-claimed Section 48E credit, subject to construction and placed-in-service deadlines, but that benefit goes to the system owner and is only partly passed on to you. State, local and utility incentives may still apply; check DSIRE.

Q: Is solar worth it for a home using 1,100 kWh per month without the federal credit?

Often yes, but payback is longer. In our model, a 9.2 kW system at $27,600 saves about $2,376 in year one at $0.18 per kWh, giving a simple payback of about 11.6 years (10–14 years across the $2.50–$3.50 per watt price range). Payback shortens with higher electricity rates, full-retail net metering and state incentives, and lengthens where utilities credit exported power at lower rates. Because 1,100 kWh is about 20% above the U.S. average household, bill savings are larger than for a typical home.

Q: How much roof space do I need for 23 panels, and does roof direction matter?

Plan on roughly 410–510 square feet of usable, unshaded roof for 23 residential panels, since each 400W panel covers about 18–22 square feet. Direction matters: south-facing roofs produce the most in the continental U.S., while east- or west-facing roofs typically produce about 10–20% less, which can mean needing a few more panels. Heavy shading can cut output further, so ask installers for a shade analysis and modeled annual kWh before you sign.

Est. net savings

$28,400

Over 25 Years (Modeled, Mid-Case) · no federal credit

$27,600 Mid-case cost (no federal credit)

11.6 yrs Payback (mid-case)

9.2 kW System size

Typical result:

≈23 panels (400W)
≈9.2 kW system
$23,000–$32,000 before incentives
≈10–14 year payback

✓ EIA rates & NREL sun data ✓ 2026 federal policy applied ✓ Open methodology

Updated October 3, 2026 · 9 min read ·By Green Energy Calculators Editorial Team

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25 years without solar vs with solar

Assumes 3%/yr rate increases, 0.5%/yr panel degradation and no federal tax credit (the 30% §25D credit ended for systems installed after Dec 31, 2025). How we calculate

Without solar

25-year utility bills

$55,969

Rates rise ~3% per year

With solar

System cost + remaining bills

$27,600

Installed cost, no federal credit

Difference

Estimated 25-year net

+$28,369

Before any state or utility incentives

Author Green Energy Calculators Editorial Team

Editorial policy No paid placements

Last updated Oct 3, 2026

Data approach EIA rates · NREL sun hours · 2026 federal policy · methodology

A home using 1,100 kWh per month typically needs about 23 solar panels (400W each, roughly 9.2 kW) at the U.S. average of about 5 peak sun hours per day. Depending on location, the count ranges from about 18 to 33 panels. The U.S. average household uses roughly 10,800 kWh per year (about 900 kWh per month), according to EIA data, so 1,100 kWh is about 20% above average. Higher use like this is common in hot climates and in homes with electric heating, electric vehicles, or pools.

Key numbers for 1,100 kWh/month (2026)

Item	Typical value
Panels needed (400W)	≈23 (range 18–33)
System size	≈9.2 kW (range 7.2–13.2 kW)
Installed cost before incentives	≈$23,000–$32,000
Federal tax credit, purchased system	None for 2026 installs
Simple payback (modeled)	≈10–14 years
Roof area needed	≈410–510 sq ft

Modeled estimates, not a quote. Assumptions are explained in the sections below.

Three variables drive the answer: peak sun hours at your location, panel wattage (most new residential panels are 400W–450W), and system losses from inverter conversion, wiring, heat, and soiling.

How to Calculate Panels Needed for 1,100 kWh per Month

The sizing formula divides your daily energy need by what one panel produces per day after losses.

Step 1 — Daily energy need: 1,100 kWh ÷ 30 days = 36.7 kWh/day

Step 2 — Output of one 400W panel per day: 0.4 kW × peak sun hours × 0.80 system efficiency

Step 3 — Panels needed: 36.7 ÷ output per panel, rounded up

At 5.0 peak sun hours, one 400W panel produces 0.4 × 5.0 × 0.80 = 1.6 kWh/day. That gives 36.7 ÷ 1.6 = 22.9, so 23 panels, or 9.2 kW.

We use a 20% loss allowance, which is deliberately conservative. NREL’s PVWatts calculator defaults to roughly 14% system losses, so a PVWatts run for your roof may show slightly fewer panels.

Panels Needed for 1,100 kWh/Month by Peak Sun Hours (calculated)

Peak Sun Hours/Day	400W Panels	System Size	450W Panels
3.5	33	13.2 kW	30
4.0	29	11.6 kW	26
4.5	26	10.4 kW	23
5.0 (≈U.S. average)	23	9.2 kW	21
5.5	21	8.4 kW	19
6.0	20	8.0 kW	17
6.5	18	7.2 kW	16

Formula: 36.7 kWh/day ÷ (panel kW × sun hours × 0.80), rounded up. Annual-average sun hours vary by dataset and tilt. As rough reference points, NREL-based sources put Phoenix near 6.5, Chicago around 4.0–4.5, and Seattle around 3.5–4.0, with a national average near 5.0. Look up your own ZIP code in PVWatts.

Panels needed for 1,100 kWh/month: 400W vs 450W. At 5.0 peak sun hours a home needs 23 panels of 400W or 21 of 450W (calculated, 20% losses). Source: NREL PVWatts sun-hour framework, 2026.

Chart summary: Panel count falls as peak sun hours rise, from 33 panels at 3.5 hours to 18 at 6.5 hours with 400W panels. At the national-average resource of about 5 hours, plan on roughly 23 panels (9.2 kW). Switching to 450W panels trims that to 21, about 9% fewer, which can help on smaller roofs.

For a location-specific figure, use our solar system size calculator. Related guides: 1,200 kWh/month and 300 kWh/month.

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What Does a Solar System for 1,100 kWh/Month Cost in 2026?

Total cost equals system watts times price per watt. Installed residential prices in 2026 generally fall between $2.50 and $3.50 per watt. EnergySage marketplace quotes averaged about $2.58 per watt in early 2026, while Lawrence Berkeley National Laboratory’s Tracking the Sun report put the 2024 median cash-purchase price near $3.50 per watt. The gap reflects different data sources: marketplace quotes versus a broad sample of installed systems.

Cost of a 9.2 kW System at Different Prices per Watt (calculated)

Price per Watt	Total Before Incentives	Source of Price Point
$2.50	$23,000	Low end of 2026 range
$2.58	$23,736	EnergySage marketplace average, early 2026
$3.00	$27,600	Mid-case used in this guide
$3.50	$32,200	LBNL 2024 cash-purchase median

Larger systems tend to cost slightly less per watt, and complex roofs, battery additions, panel brand, and regional labor rates move the number up or down. Equipment is only part of the bill; labor, permitting, interconnection, and installer overhead make up a large share, which is why quotes for similar systems can differ by thousands of dollars.

Cost of a 9.2 kW system before incentives, by price per watt. Totals range from $23,000 at $2.50/W to $32,200 at $3.50/W, with no federal credit for 2026 purchases. Source: EnergySage 2026 and LBNL Tracking the Sun, calculated as 9,200 W × $/W.

Chart summary: A 9.2 kW system costs between about $23,000 and $32,200 before incentives, a spread of roughly $9,200 driven mostly by installer pricing and data source. The $3.00 per watt midpoint ($27,600) is the cost used for the payback modeling below. Because quotes vary this widely, get at least three written bids and compare them on price per watt, equipment, warranty, and modeled annual production.

See your state’s price and incentive context on our state pages, including California, New York, and Massachusetts.

Solar vs utility company · 25-year comparison

25-year totals: 3%/yr rate increases, 0.5%/yr degradation, no federal credit. Methodology

Total utility payments

$55,969

Total solar cost (installed + remaining bills)

$27,600

Net savings

+$28,369

Avg. monthly difference

+$198/mo

See my savings →

Do Solar Tax Credits Still Apply in 2026?

For systems you buy with cash or a loan, no. The 30% Residential Clean Energy Credit (Section 25D) was terminated by the One Big Beautiful Bill Act, signed July 4, 2025, for expenditures made after December 31, 2025. Older guides that subtract 30% from system cost no longer apply to homeowner-owned systems installed in 2026.

What this means in practice:

Installed and operating by December 31, 2025: the 30% credit applied, and any unused amount can generally be carried forward to later tax years. Confirm details with a tax professional or the IRS residential clean energy credit page.
Purchased in 2026 or later: no federal homeowner credit. Plan using the gross cost, minus only documented state, local, or utility incentives.
Leases and PPAs: the system’s owner (a company) may still claim the business investment credit (Section 48E), which remains available for residential solar subject to construction-start and placed-in-service deadlines. Any benefit reaches you only indirectly through the contract terms, so ask the provider how the credit affects your price.

State and local programs vary widely and include income tax credits, rebates, sales tax exemptions, property tax exclusions, and net metering. Check DSIRE for programs in your state.

Solar Payback Period When Offsetting 1,100 kWh per Month

Simple payback equals system cost divided by first-year bill savings. Our model uses these assumptions:

Annual production offset: 13,200 kWh (1,100 kWh × 12), assumed to fully offset use
Electricity rate: $0.18 per kWh. EIA data put the U.S. average residential rate at roughly 17–19 cents per kWh across 2025 and early 2026; use your own bill’s rate.
First-year savings: 13,200 × $0.18 = $2,376 (about $198 per month)
Panel degradation: 0.5% per year, a commonly used planning assumption
Rate escalation: 0% in the main model (conservative); a 2% scenario is shown for comparison
Federal tax credit: none (purchased system installed in 2026)

Modeled Payback and 25-Year Net Savings, 9.2 kW System (calculated)

Price per Watt	System Cost	Simple Payback	25-Yr Net, Flat Rate	25-Yr Net, 2% Rate Growth
$2.58	$23,736	10.0 yrs	$32,233	$47,604
$3.00 (mid-case)	$27,600	11.6 yrs	$28,369	$43,740
$3.50	$32,200	13.6 yrs	$23,769	$39,140

25-year net = cumulative avoided electricity cost minus system cost. Excludes financing costs, inverter replacement, maintenance, and taxes.

Cumulative net cash flow of a 9.2 kW cash-purchase system, Year 0–25. The $27,600 mid-case turns positive around year 12 and ends near +$28,369, assuming $0.18/kWh, 0% annual rate escalation, 0.5% panel degradation, and no federal credit. Source: EIA rates, NREL PVWatts losses, LBNL prices, 2026.

Chart summary: With no federal credit and flat 0% electricity-rate escalation, a 9.2 kW system pays for itself in roughly 10 to 14 years depending on price, and the $3.00 per watt mid-case breaks even around year 12. By year 25 the modeled net gain ranges from about $23,800 to $32,200, and a 2% annual rate increase would lift that to roughly $39,100–$47,600. Payback is faster with high local rates and full-retail net metering, and slower where exports earn lower credits.

Use our solar payback calculator or solar savings calculator with your own rate and quote.

Cash vs Loan vs Lease for a 1,100 kWh/Month Solar System

How you pay changes both your cash flow and who captures the long-term savings. The loan figures below are an illustration using the mid-case $27,600 price and an assumed 6.9% rate; actual rates, terms, and fees vary by lender.

Option	Upfront Cost	Monthly Payment	Ownership	Notes
Cash purchase	$27,600 (mid-case)	None	You own the system	Highest long-term savings; no federal credit in 2026
Solar loan (6.9%, 15 years, illustrative)	Often $0 down	≈$247/month; ≈$16,800 total interest	You own the system	Payment exceeds first-year savings (≈$198/month) in this example
Lease or PPA	Typically little or none	Fixed lease payment, or a per-kWh rate	Provider owns the system	Check escalators, term length, and what happens if you sell the home

In this example the loan payment ($247) is higher than the average first-year savings ($198 per month), so the loan runs cash-flow negative in the early years. Longer terms, lower rates, or rising electricity prices change that. Ask lenders whether the quoted price includes financing fees, since those can raise the effective system cost.

Leases and PPAs reduce or remove upfront cost, but you give up ownership and most of the long-term savings. Request the full contract and compare the total expected payments against the modeled savings above before signing.

Even without net metering, solar can still offset daytime use such as air conditioning and appliances, but self-consumption rules and export credit rates differ by utility. Check your utility’s current policy first.

Methodology and Sources

All panel counts, costs, payback figures, and charts on this page are calculated from the formulas and assumptions stated above. They are not measurements from a specific installation. Last updated October 3, 2026.

Household electricity use: U.S. Energy Information Administration, Residential Energy Consumption Survey
Electricity rates: U.S. Energy Information Administration, Electric Power Monthly
Solar resource and loss assumptions: National Renewable Energy Laboratory, PVWatts Calculator
Installed prices: Lawrence Berkeley National Laboratory, Tracking the Sun; EnergySage marketplace data (early 2026)
Federal tax policy: IRS Residential Clean Energy Credit; Public Law 119-21 (One Big Beautiful Bill Act)
State and local incentives: DSIRE database

This guide provides general estimates for planning and is not a quote, tax advice, or financial advice. Prices, utility policies, and tax law change; confirm current rules and get written installer quotes before buying.

Frequently asked questions

Direct answers for US homeowners — sized for a $198/month electric bill.

How many solar panels do I need for 1,100 kWh per month?

Most homes need about 23 panels of 400W (roughly 9.2 kW) to offset 1,100 kWh per month at the U.S. average of about 5 peak sun hours. The count falls to around 18 panels in very sunny locations (about 6.5 sun hours) and rises to around 33 in cloudy ones (about 3.5 sun hours). Using 450W panels reduces the typical count to about 21. Enter your ZIP code in a PVWatts-based calculator to get a location-specific number.

How much does a solar system for 1,100 kWh per month cost in 2026?

Is the 30% federal solar tax credit still available in 2026?

Is solar worth it for a home using 1,100 kWh per month without the federal credit?

How much roof space do I need for 23 panels, and does roof direction matter?

Same usage, bill-based guide

Your 1,100 kWh/Month target maps to roughly a $175/month electric bill nationally.

$175 $175/month electric bill guide Panels · cost · payback · by state →

Popular state solar guides

Electricity rates and incentives vary — see data for your state.

CA California 33.25¢/kWh · 5.8h sun TX Texas 16.06¢/kWh · 5.6h sun FL Florida 15.3¢/kWh · 5.7h sun AZ Arizona 15.44¢/kWh · 6.5h sun NC North Carolina 14.94¢/kWh · 5.2h sun NY New York 29.38¢/kWh · 4.3h sun MA Massachusetts 30.14¢/kWh · 4.2h sun CO Colorado 16.72¢/kWh · 5.5h sun

View all 50 states →

How these numbers were calculated

Electricity rate: 18.19¢/kWh — US average residential price. Source: EIA Electric Power Monthly, Table 5.6.B (year-to-date through July 2026), residential average retail price (July 2026) (EIA)
Solar production: 4.5 peak sun hours/day × 0.82 system derate. Approximate state-average daily solar resource (peak sun hours) based on NREL solar resource data (NSRDB); not location-specific — use NREL PVWatts for an address-level estimate. (NREL PVWatts)
Installed price: $3.00 per watt before incentives. Blended 2026 US residential installed price used by this site; EnergySage marketplace reported about $2.60/W (mid-2026); full-market medians are higher.
Federal tax credit: $0 for homeowner-owned systems installed in 2026 — the 30% §25D credit ended Dec 31, 2025 (IRS)
Net metering: National blend — solar assumed to offset 75% of the bill (87% in full-retail net-metering states, 55–70% elsewhere).
Model: Version 2026.10 · 3%/yr electricity price escalation · 0.5%/yr panel degradation · simple payback = installed cost ÷ year-1 savings
Policy checked: September 29, 2026 · Full methodology · Report an error

Estimates only — not tax, legal or financial advice. Get at least three installer quotes and confirm incentives with your utility and a tax professional.