US residential solar · 2026 data

Solar Panels for a $100/Month Electric Bill

Q: How much does solar cost for a $100 bill, and is there a federal tax credit in 2026?

A ~4.75 kW system typically costs about $11,900–$16,600 before incentives at $2.50–$3.50 per watt. The 30% federal Residential Clean Energy Credit (Section 25D) ended December 31, 2025, so homeowners who buy with cash or a loan in 2026 receive no federal credit. State, local and utility incentives still exist in some areas, so check DSIRE and collect at least three quotes.

Q: Is solar worth it if my electric bill is only $100 a month?

It depends mostly on your electricity rate. In high-rate states such as Hawaii, California, Massachusetts and New York, a $100 bill needs a small, inexpensive system and our model shows simple payback of roughly 5–9 years. In low-rate states such as Louisiana, payback can exceed 15 years without incentives. Solar fits best if you will stay in the home 10+ years and your utility credits exported power at or near the retail rate.

Q: How long does it take solar to pay for itself on a $100 bill?

At national-average rates our model shows about 12 years with flat electricity prices and about 10.7 years if rates rise 3% per year (cash purchase, $2.75 per watt, no incentives). State results range from about 5 years in Hawaii to about 17 years in Louisiana. Loan interest lengthens payback, and leases or PPAs have no upfront cost but you do not own the system.

Q: Will solar eliminate my $100 electric bill entirely?

Rarely. A properly sized system can offset most or all of your kWh usage, but utilities typically charge fixed monthly customer fees that solar cannot offset, and some states credit exported power below the retail rate. Our model assumes solar removes about 90% of the bill. Use our [solar payback calculator](/calculators/solar-payback/) to model your break-even year with your own rate, sun hours and incentives.

Est. net savings

$23,700

Over 25 Years (modeled) · no federal credit

$13,100 Cost before incentives

10.7 yrs Payback (3%/yr rate growth)

4.75 kW System size

Typical result:

~12 panels
~4.75 kW system
~$13,100 before incentives
~11–12 year payback

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

Updated October 3, 2026 · 10 min read ·By Green Energy Calculators Editorial Team

Calculate My Savings View State Incentives

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

$36,800

Rates rise ~3% per year

With solar

System cost + remaining bills

$13,100

Installed cost, no federal credit

Difference

Estimated 25-year net

+$23,700

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 $100 monthly electric bill equals about 546 kWh at the 2026 US-average residential rate of 18.31¢/kWh (EIA, July 2026). In an average-sun location, offsetting that usage takes roughly 12 panels (about 4.75 kW), which costs about $13,100 before incentives at $2.75 per watt. Because the 30% federal Residential Clean Energy Credit (Section 25D) ended on December 31, 2025, homeowners who buy with cash or a loan in 2026 pay that full price — so payback depends mainly on your state’s electricity rate, your sun exposure and your utility’s net-metering rules. This guide shows the math step by step, compares sample US cities and states, and models payback using assumptions you can check.

Updated October 3, 2026: corrected the federal tax-credit status, refreshed electricity rates to EIA’s July 2026 data, fixed the system-sizing formula and replaced all charts with figures calculated from the assumptions stated below.

How Many kWh Does a $100 Electricity Bill Represent?

To size a solar system, first convert dollars to kilowatt-hours using the formula Monthly kWh = Monthly bill ÷ Rate ($/kWh). According to EIA’s Electric Power Monthly, the US residential average price was 18.31¢/kWh in July 2026, ranging from 12.72¢ in Louisiana to 48.00¢ in Hawaii.

At the national average: $100 ÷ $0.1831 = 546 kWh per month, or about 18 kWh per day. For context, EIA-derived figures put the average US household bill at roughly $212 in July 2026 (a high-usage summer month), so a $100 bill signals below-average usage — which also means a smaller system.

State	Avg residential rate (¢/kWh, Jul 2026)	kWh per $100	Approx. system size*
Hawaii	48.00	208	1.8 kW
California	33.61	298	2.6 kW
Massachusetts	30.49	328	2.9 kW
Connecticut	24.16	414	3.6 kW
US average	18.31	546	4.75 kW
Texas	15.88	630	5.5 kW
North Carolina	15.16	660	5.7 kW
Louisiana	12.72	786	6.8 kW

Source: EIA Electric Power Monthly, Table 5.6.A (July 2026). *System size assumes 4.5 peak sun hours and a 0.84 derate in every state to isolate the effect of price; real sun hours vary by location (see next section).

EIA’s price is total revenue divided by total kWh sold, so it includes fixed charges. Treat these kWh figures as estimates and check the usage line on your own bill. Our solar system size calculator lets you enter your exact bill and rate.

Monthly kWh a $100 Electric Bill Buys, by State. Calculated as $100 ÷ each state’s average residential rate. Source: EIA Electric Power Monthly, Table 5.6.A, July 2026.

Chart summary: The same $100 buys 786 kWh in Louisiana but only 208 kWh in Hawaii — about 3.8 times more electricity. More kWh per dollar means a larger system is needed to offset the bill, which is why a $100 bill is a small solar project in high-rate states and a large one in low-rate states. The orange bar marks the US average of 546 kWh.

Run the numbers for your state

The savings calculator loads your state's average electricity rate, sun hours and net-metering rule. Then enter your own bill and installer quote.

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What Solar System Size Do You Need to Offset a $100 Bill?

Once you know your monthly kWh, the DC system size follows from your location’s peak sun hours (the NREL solar-resource figure available through PVWatts).

Step 1 — Daily kWh target: 546 kWh × 12 months ÷ 365 days = about 18 kWh per day (US-average rate).

Step 2 — DC system size: System (kW) = Daily kWh ÷ (Peak sun hours × Derate factor)

We use a 0.84 derate (about 16% total losses from heat, soiling, wiring, inverter and shading). That is slightly more conservative than the roughly 14% system-loss default in PVWatts, so a PVWatts run for your roof may return a slightly smaller system.

Example (average sun, 4.5 peak sun hours): 17.96 ÷ (4.5 × 0.84) = 4.75 kW, or 4.75 ÷ 0.4 = about 12 panels (400W each).

Sample city	Approx. peak sun hours	State rate (¢/kWh)	kWh per $100	System needed	Panels (400W)
Phoenix, AZ	6.2	15.38	650	4.1 kW	11
Denver, CO	5.4	17.00	588	4.3 kW	11
Charlotte, NC	4.8	15.16	660	5.4 kW	14
Chicago, IL	4.1	19.22	520	5.0 kW	13
Seattle, WA	3.5	14.71	680	7.6 kW	20

Peak sun hours are approximate annual averages for a well-oriented array; confirm your ZIP code in PVWatts. Rates: EIA, July 2026. Panel counts are rounded up.

Two homes with the same $100 bill can need very different systems: Phoenix needs about 11 panels, while Seattle — with lower sun and a similar rate — needs about 20. Roof direction matters too. East- and west-facing roofs produce less than a south-facing roof, so an installer should give you a production estimate for your exact roof, tilt and shading rather than a generic panel count.

For current installed prices, see our guide to How Much Do Solar Panels Cost in 2026?. If your usage is higher, compare with our guide to Solar Panels for a $125 Electric Bill.

What Does It Cost to Install Solar for a $100 Electricity Bill?

Residential solar in 2026 is commonly priced at about $2.50–$3.50 per watt installed, before incentives, based on installer and marketplace pricing published by several US solar cost guides. Smaller systems often cost more per watt than larger ones, and Northeast and California markets tend to sit at the high end. We use $2.75/W as the midpoint for the models in this guide.

System size	At $2.50/W	At $2.75/W (model)	At $3.50/W
4 kW	$10,000	$11,000	$14,000
4.75 kW (US-average $100 bill)	$11,875	$13,063	$16,625
5 kW	$12,500	$13,750	$17,500
6 kW	$15,000	$16,500	$21,000

Gross cost = system kW × 1,000 × $/W. These are before-incentive figures: the federal homeowner credit does not apply to systems placed in service in 2026 (see next section).

Estimated Installed Cost by System Size at Three Price Points. Calculated as kW × 1,000 × $/W with no incentives subtracted. Price range reflects typical 2026 US installed pricing.

Chart summary: Moving from $2.50 to $3.50 per watt adds about $4,000 to a 4 kW system and $6,000 to a 6 kW system. Green, yellow and red bars show the low, midpoint and high price scenarios. Price per watt matters as much as system size, so comparing at least three written quotes is the easiest way to lower your cost.

Is There Still a Federal Solar Tax Credit in 2026?

No — not for homeowners who buy a system. The One Big Beautiful Bill Act (Public Law 119-21, signed July 4, 2025) ended the 30% Residential Clean Energy Credit (Section 25D) for expenditures made after December 31, 2025, according to the IRS. A cash or loan purchase completed in 2026 therefore receives no federal credit. Many older guides still show a 30% discount; those figures are out of date.

What still exists in 2026:

Carryforward of unused credit. If you installed a system in 2025 and could not use the whole credit, the unused portion can generally carry forward to later tax years. Confirm with a tax professional.
Leases and power purchase agreements (PPAs). A company that owns the panels may still be eligible for the commercial credit (Section 48E) under the law’s deadlines — generally projects that began construction by July 4, 2026 or are placed in service by the end of 2027. Whether any of that value reaches you depends on the contract.
State, local and utility programs. Rebates, state tax credits, performance incentives, sales- and property-tax exemptions and net-metering rules vary by location and change often. Check DSIRE and our state incentives pages.

How Long Does Solar Payback Take When You Spend $100/Month?

Simple payback is the net system cost divided by annual savings. Our model uses these stated assumptions:

4.75 kW system sized for the US-average $100 bill, costing $13,063 ($2.75/W) with no incentives
Solar offsets about 90% of the bill ($1,080 in year 1); the remaining 10% covers fixed utility charges
Panel output declines 0.5% per year
Two electricity-price scenarios: 0% growth and 3% annual growth
Cash purchase; inverter replacement, maintenance and financing costs are not included

Scenario (cash purchase)	Net cost	Year-1 savings	Break-even	25-year net savings
Flat electricity prices	$13,063	$1,080	~12.4 years	~$12,400
3% annual price growth	$13,063	$1,080	~10.7 years	~$23,800

Because every household in this example spends the same $100, payback differs by state mainly because lower-rate states need larger, costlier systems to offset the same bill:

State	Rate (¢/kWh)	System (kW)	Est. cost at $2.75/W	Simple payback (flat rates)
Hawaii	48.00	1.8	~$4,980	~4.6 years
California	33.61	2.6	~$7,120	~6.6 years
Massachusetts	30.49	2.9	~$7,850	~7.3 years
New York	29.90	2.9	~$8,000	~7.4 years
Connecticut	24.16	3.6	~$9,900	~9.2 years
US average	18.31	4.75	~$13,060	~12.1 years
Texas	15.88	5.5	~$15,060	~13.9 years
North Carolina	15.16	5.7	~$15,780	~14.6 years
Louisiana	12.72	6.8	~$18,800	~17.4 years

Simple payback = cost ÷ $1,080 annual savings, with no degradation or price growth. All states use 4.5 peak sun hours and $2.75/W so that the table isolates the effect of the electricity rate. Real results shift with local sun, installed price and incentives. In states with reduced export credits (for example California’s net billing), payback can be longer than shown.

Financing. A solar loan adds interest, which lengthens payback compared with paying cash; use the loan terms in your quote with our solar loan payment calculator. A lease or PPA has no upfront cost but you do not own the system, and savings depend on the contract’s rate and escalator.

25-Year Cumulative Net Cash Flow — 4.75 kW Cash Purchase, No Incentives. Break-even falls near year 12 with 0% price growth and year 11 with 3% growth on a $13,063 system. Source: EIA 2026 rates; modeled with the stated assumptions.

Chart summary: Both lines start at about −$13,100 and cross zero at roughly year 12 (flat prices) or year 11 (3% growth). By year 25 the modeled net gain is about $12,400 with flat prices and about $23,800 with 3% annual price growth. The gap shows how much of solar’s value depends on future electricity prices — a number no one can guarantee.

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

$36,800

Total solar cost (installed + remaining bills)

$13,100

Net savings

+$23,700

Avg. monthly difference

+$79/mo

See my savings →

Is Solar Worth It If You Only Spend $100 a Month on Electricity?

It can be, but the case is weaker than for higher bills, and in 2026 it no longer has a federal credit behind it. Your annual electricity spend is $1,200; a system sized to offset it costs roughly $5,000–$19,000 before incentives depending on your state, so the math works comfortably only if you expect to stay in the home long enough to pass break-even.

Where solar makes sense at $100/month:

High-rate states (HI, CA, MA, NY, CT), where $100 buys fewer kWh and a smaller, cheaper system covers it
Areas with net metering or export credits at or near the retail rate, plus state or utility incentives
Homeowners planning to stay 10+ years and paying cash or low-interest financing

Where the math is tighter:

Low-rate states (for example LA, TX, NC), where $100 buys 630–790 kWh and needs a 5.5–7 kW system at $15,000+ before incentives
Utilities that credit exported power well below the retail rate
Financing at high interest rates, or a short time horizon

Solar can also raise a home’s sale price. A 2015 Lawrence Berkeley National Laboratory study, Selling into the Sun, analyzed about 22,800 home sales (2002–2013) in eight states and found buyers paid an average premium of roughly $4 per watt — about $15,000 for a typical 3.6 kW system — for host-owned systems. The study is a decade old, covered specific markets and reported that premiums fell as systems aged, so treat it as a directional benefit, not a guaranteed return.

Use our solar savings calculator to enter your own rate, sun hours and incentives before talking to an installer.

Methodology and Sources

Electricity rates: EIA, Electric Power Monthly, Table 5.6.A, residential average retail price by state, July 2026.
Sun and production: approximate annual peak sun hours; confirm with NREL PVWatts. Our 0.84 derate is conservative relative to PVWatts’ default.
Installed cost: $2.50–$3.50/W typical 2026 pre-incentive range from published industry cost guides; $2.75/W midpoint is our modeling assumption. Get at least three quotes for your home.
Federal tax credit: IRS Residential Clean Energy Credit; One Big Beautiful Bill Act (Public Law 119-21).
State incentives: DSIRE database.
Home-value research: Hoen et al., Selling into the Sun, Lawrence Berkeley National Laboratory (2015).
Models: all payback and cash-flow figures are calculations from the assumptions stated in this article, not measured results from specific installed systems. This guide is general information, not tax or financial advice; confirm tax questions with a qualified professional.

Frequently asked questions

Direct answers for US homeowners — sized for a $100/month electric bill.

How many solar panels do I need for a $100/month electric bill?

About 12 panels (roughly 4.75 kW of 400W panels) at the US-average rate of 18.31¢/kWh and 4.5 peak sun hours, which equals about 546 kWh per month. High-rate states need far fewer panels (about 5 in Hawaii, 7 in California), while low-rate or cloudy markets need more (about 18 in Louisiana at average sun, roughly 20 in Seattle). Enter your ZIP code in NREL PVWatts for a precise count.

How much does solar cost for a $100 bill, and is there a federal tax credit in 2026?

Is solar worth it if my electric bill is only $100 a month?

How long does it take solar to pay for itself on a $100 bill?

Will solar eliminate my $100 electric bill entirely?

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.