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
Data approachEIA rates · NREL sun hours · 2026 federal policy · methodology
A 4,800 sq ft house typically needs 35 to 70 solar panels (400W each, or 14–28 kW). For a home that uses about 26,000 kWh a year, roughly a $400 monthly electric bill, a good starting point is about 50 panels (20 kW). At an assumed $2.75 per watt, that system costs around $55,000 before incentives.
One change matters more than any other in 2026: the 30% federal tax credit for homeowners who buy solar ended for systems paid for after December 31, 2025. Older guides that quote “after-credit” prices are out of date. This guide uses current costs and shows the math so you can check it against your own bills.
Last updated: September 30, 2026. Figures are planning estimates, not quotes.
⚡ System Size
How to Calculate Solar Panel Count for a 4,800 Sq Ft Home
Square footage is a weak predictor of solar needs. Two 4,800 sq ft homes can use very different amounts of electricity depending on climate, heating fuel (gas vs. electric), pool equipment, EV charging, and household size. The EIA Residential Energy Consumption Survey shows that consumption varies widely with these factors, so start with your actual bills.
The four-step sizing formula:
Annual consumption (kWh): Add up 12 months of bills. Example: 26,280 kWh.
Daily average: Divide by 365. Example: 72 kWh/day.
System size (kW): Divide by your location’s daily peak sun hours, then by 0.80 to cover real-world losses (inverter, wiring, heat, dirt, minor shading). With 4.5 sun hours: 72 ÷ 4.5 ÷ 0.80 = 20.0 kW.
Panel count: Divide system watts by panel wattage. 20,000 W ÷ 400 W = 50 panels.
The 0.80 factor is deliberately conservative; NREL’s PVWatts calculator defaults to roughly 14% system losses. A 400W panel covers about 20–21 sq ft, so 50 panels need roughly 1,000 sq ft of usable roof.
Solar panels needed for a 4,800 sq ft home by usage profile (2026 planning scenarios)
Home profile
Annual kWh
System size
Panels (400W)
Gas heat, mild climate
18,000
13.7 kW
35
Base case (~$400/mo bill)
26,280
20.0 kW
50
All-electric, heavy A/C
36,000
27.4 kW
69
All-electric + EV charging
42,000
32.0 kW
80
Profiles are illustrative scenarios, not national averages. All use 4.5 peak sun hours and 80% system efficiency.
Panel count scales with usage, from 35 to 80 panels. An all-electric home with EV charging needs about 80 panels at 400W each. Source: formula in this guide, 4.5 peak sun hours (NREL PVWatts) and 80% system efficiency.
Chart summary: Panel count rises in direct proportion to annual kWh, from 35 panels at 18,000 kWh to 80 panels at 42,000 kWh. Moving from the base case to an all-electric home with EV charging adds roughly 20–30 panels. Your bills, not your square footage, should set the size.
Roof direction and shading. East- and west-facing roof planes usually produce somewhat less than south-facing ones, and shade can cut output sharply. Ask each installer for modeled production per roof plane. Microinverters or power optimizers can limit shading losses on complex rooflines, which are common on large homes.
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.
Free · No signup · Runs in your browser
💰 System Cost
What Does Solar Cost for a 4,800 Sq Ft Home in 2026?
Most 2026 estimates put installed residential solar between $2.50 and $3.50 per watt before incentives. Marketplace quote data tends to sit near the low end, while installed-price datasets such as Lawrence Berkeley National Laboratory’s Tracking the Sun tend to run higher. Larger systems usually cost less per watt, but your roof, equipment, and local labor rates matter. Our base case uses $2.75 per watt.
Solar system cost by size for a 4,800 sq ft home (2026 estimates, 4.5 sun hours, 18.2¢/kWh)
System size
Gross cost ($2.50–$3.50/W)
Est. annual output
Est. bill savings per month
12 kW
$30,000–$42,000
~15,800 kWh
~$240
15 kW
$37,500–$52,500
~19,700 kWh
~$300
20 kW
$50,000–$70,000
~26,300 kWh
~$400
25 kW
$62,500–$87,500
~32,900 kWh
~$500
Savings assume every kWh produced offsets a kWh you would otherwise buy at the 18.2¢ U.S. average. The EIA Short-Term Energy Outlook projects the 2026 U.S. residential average at about 18.2¢/kWh. Your rate and export credit will differ.
Financing. Interest raises your lifetime cost. A $55,000 loan at 7% over 15 years costs about $494 a month, which is higher than the ~$400 bill it offsets, so cash flow is negative until the loan ends. Compare loan terms with our solar loan calculator.
Leases and PPAs. These require little or no money upfront, but you don’t own the system, and the provider keeps the tax benefits and much of the savings. Read the annual price-escalator clause and the buyout terms before signing.
Solar vs utility company · 25-year comparison
25-year totals: 3%/yr rate increases, 0.5%/yr degradation, no federal credit. Methodology
For homeowners who buy a system, no. The Residential Clean Energy Credit (Section 25D), worth 30% of costs, ended for expenditures made after December 31, 2025, under the One Big Beautiful Bill Act (Public Law 119-21). See the IRS credit page for the current status.
What still exists:
Carryforward: Unused 25D credit from a system completed in 2025 or earlier can be carried into later tax years.
Third-party-owned systems: Leases and PPAs can still use the business credit under Section 48E if they meet its deadlines, which tie to when construction began or when the system is placed in service. Whether any of that value reaches you depends on the provider’s contract.
State and local incentives: These vary widely. New York offers a state credit of 25% up to $5,000, and Florida exempts the added home value from solar from property tax. Confirm current terms on DSIRE before signing, since programs change.
Net metering and export rules: These now affect savings as much as tax credits. California’s NEM 3.0 pays much less for exported power than the retail rate.
This is general information, not tax advice; talk to a tax professional about your situation.
⚡ System Size
How Peak Sun Hours by State Change Your Panel Count
Peak sun hours measure how much usable sunlight your location receives each day. The same home needs far more panels in a cloudy region than a sunny one.
Panels needed by state for a 30,000 kWh/year home (2026 estimates)
State
Approx. peak sun hours
System size needed
Panels (400W)
Arizona
5.8
17.7 kW
45
California
5.3
19.4 kW
49
Texas
5.0
20.5 kW
52
Georgia
4.7
21.9 kW
55
New York
4.3
23.9 kW
60
Washington
3.8
27.0 kW
68
Sun-hour values are rounded planning averages. Look up your exact address in PVWatts. System size = 30,000 ÷ 365 ÷ sun hours ÷ 0.80.
Data visualization
The same home needs 45 panels in Arizona and 68 in Washington. Counts use a 30,000 kWh/year load and 400W panels. Source: approximate state-average peak sun hours (NREL), 80% system efficiency.
Chart summary: For identical electricity use, a Washington home needs about 50% more panels than an Arizona home (68 vs. 45). More panels do not automatically mean worse economics. Electricity prices in California and New York are well above the 18.2¢ U.S. average per EIA data, while lower-rate sunny states may save less per kWh.
Export policy matters too. States and utilities that credit exported power near the retail rate shorten payback. Where exports earn only a fraction of retail, as under California’s NEM 3.0, self-consumption and batteries matter more. Read your utility’s current tariff before choosing a system size.
Is Solar Worth the Investment for a 4,800 Sq Ft Home?
Often yes, but with no federal credit the payback is longer than older guides claim. The key is how much of your electricity bill the system offsets, and at what rate.
Base case (20 kW, 26,280 kWh/yr, $55,000, 18.2¢/kWh):
Year-1 savings: about $4,780 (roughly $400 a month)
Simple payback: about 11.5 years; about 11.8 years after 0.5% annual panel degradation
If rates rise 2% a year: payback about 10.7 years
25-year net savings: about $57,700 at flat rates, or about $88,600 with 2% annual rate growth
These figures exclude financing costs, maintenance, and any inverter replacement, which can arrive within the system’s life.
Data visualization
A $55,000 cash purchase breaks even near year 12 at flat rates. Cumulative net position uses 26,280 kWh in year 1, 18.2 cents per kWh (EIA 2026 outlook), 0.5% yearly degradation, and either 0% or 2% yearly rate growth, with no federal credit.
Chart summary: The system recovers its $55,000 cost around year 12 at flat rates (about year 11 if rates climb 2% annually) and ends year 25 roughly $58,000 to $89,000 ahead. Rising electricity prices improve the result but are not guaranteed. The 0.5% yearly degradation rate is based on NREL’s degradation review; results exclude financing, maintenance, and inverter replacement.
Rates are rising, but not evenly. EIA data show the U.S. average residential price rose about 7% in the 12 months to April 2026. Past increases don’t guarantee future ones, which is why we show both flat and rising-rate cases.
When solar may not pay off:
Your electricity rate is low (below the national average) and exports earn little
Your roof is heavily shaded or has little usable south, east, or west area
You expect to move before the payback period ends
Your utility limits system size or pays very low export rates
📋 Key Insights
How to Get an Accurate Solar Quote for a 4,800 Sq Ft Home
Quotes for the same home can differ widely because of panel brand, inverter type, labor, and overhead. The cheapest quote is not always the best value. Compare price per watt, estimated annual kWh, warranty terms, and installer track record together.
Five steps to a reliable quote:
Gather 12–24 months of utility bills. Large homes often have seasonal swings, and a second year shows a fuller picture.
Request a shading analysis. Installers commonly use tools such as Aurora Solar or HelioScope to model shade by season.
Tell installers about future loads. If you plan an EV, heat pump, or pool, size for it now; ask what adding panels later would cost.
Compare at least three itemized quotes built on the same annual kWh target.
Verify incentives and export rates independently. Check DSIRE and your utility’s current tariff, since programs and rates change.
For a complex roof, a site visit is worth requiring before you sign. Ask whether the installer offers a written production guarantee, and what it covers. Use our solar savings calculator to compare quotes against expected lifetime savings.
Sources and Methodology
Sizing formula: annual kWh ÷ 365 ÷ peak sun hours ÷ 0.80 system efficiency ÷ panel wattage. NREL PVWatts can model your exact address.
Electricity price: U.S. Energy Information Administration, Short-Term Energy Outlook (2026 U.S. residential average ≈ 18.2¢/kWh) and Electric Power Monthly.
Installed cost: Ranges of $2.50–$3.50 per watt reflect published 2026 estimates (SEIA/Wood Mackenzie, EnergySage, and Lawrence Berkeley National Laboratory data); we use $2.75/W for the base case.
Scenarios and state sun-hour values are our planning estimates, calculated with the stated formula and assumptions. They are not guarantees or quotes, and this article is not tax or financial advice.
Related calculators
Free tools for US homeowners — instant results, all 50 states.
Direct answers for US homeowners — sized for a $400/month electric bill.
Most 4,800 sq ft homes need about 35 to 70 panels (400W each, 14–28 kW), depending on electricity use and local sunlight. A home using roughly 26,000 kWh a year, about a $400 monthly bill, needs around 50 panels (20 kW) at 4.5 peak sun hours. To size your own: annual kWh ÷ 365 ÷ daily peak sun hours ÷ 0.80 gives the kW needed; divide by panel wattage for panel count.
Most 2026 estimates fall between $2.50 and $3.50 per watt before incentives. A 20 kW system, the base case for this home, costs roughly $50,000–$70,000, or about $55,000 at $2.75 per watt. Because the federal homeowner credit ended after 2025, that is close to your net cost for a purchase, before any state, local, or utility incentive.
Not for homeowners who buy a system. The 30% Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, under Public Law 119-21. Unused credit from earlier systems can still be carried forward. Third-party-owned systems (leases and PPAs) may still use the business credit under Section 48E, subject to deadlines. Confirm details with a tax professional.
Without incentives, simple payback is roughly 10.5 to 14.6 years at $2.50–$3.50 per watt and the 18.2¢/kWh U.S. average rate, for a system that offsets most of your usage. Our 20 kW base case pays back in about 11.8 years at flat rates, or about 10.7 years if rates rise 2% a year. Payback is shorter where electricity is expensive and exports are credited near retail.
Often, but not always. Under full retail net metering, covering most of your annual use works well. Under net billing, such as California's NEM 3.0, exported power earns far less than retail, so a system sized closer to your daytime use, or paired with a battery, may pay back faster. Add panels now for a planned EV or heat pump, and check whether your utility caps system size relative to past usage.
Same usage, bill-based guide
Your 4,800 sq ft House target maps to roughly a $400/month electric bill nationally.
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).
Estimates only — not tax, legal or financial advice. Get at least three installer quotes and confirm incentives with your utility and a tax professional.