Solar Panels for 800 kWh/Month: Panel Count, Cost & Payback (2026)
Est. net savings
$31,500
Over 25 Years (modeled estimate) · no federal credit
Typical result:
- 13–24 panels (about 19 typical)
- About 7.3 kW system
- About $21,000 before incentives
- About 11-year payback (estimate)
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
$52,500
Rates rise ~3% per year
With solar
System cost + remaining bills
$21,000
Installed cost, no federal credit
Difference
Estimated 25-year net
+$31,500
Before any state or utility incentives
How Many Solar Panels Do You Need for 800 kWh/Month?
The sizing formula divides your annual usage by the energy one kilowatt of panels produces in a year:
System size (kW) = Annual kWh ÷ (Peak Sun Hours × 365 × System Efficiency)
For 800 kWh/month (9,600 kWh/year), 4.5 peak sun hours and 80% efficiency:
9,600 ÷ (4.5 × 365 × 0.80) = 7.3 kW, or 19 panels at 400 W each
Panel count falls as sun hours rise. Use the table to find the row closest to your location, then confirm your exact figure in NREL’s PVWatts calculator or our solar system size calculator.
Panels needed for 800 kWh/month by peak sun hours (400 W panels, 80% efficiency)
| Peak Sun Hours/Day | System Size | Panels (400 W) | Roughly Typical Of |
|---|---|---|---|
| 3.5 | 9.4 kW | 24 | Pacific Northwest, e.g. Seattle |
| 4.0 | 8.2 kW | 21 | Great Lakes and Northeast, e.g. Chicago |
| 4.5 | 7.3 kW | 19 | U.S. typical |
| 5.0 | 6.6 kW | 17 | Parts of the South and Mountain West |
| 5.5 | 6.0 kW | 15 | Sunny Southwest and Mountain West |
| 6.0 | 5.5 kW | 14 | Desert Southwest, e.g. Phoenix |
| 6.5 | 5.1 kW | 13 | Sunniest U.S. locations |
Location examples are approximate; peak sun hours vary by site, tilt, and shading. Panel counts are rounded up.
Chart summary: Moving from 3.5 to 6.5 peak sun hours cuts the panel count from 24 to 13, so location can change the system by about 11 panels. At the U.S.-typical 4.5 sun hours you need about 19 panels. Panel wattage matters too: the same 7.3 kW system is about 17 panels at 440 W or 21 at 350 W. For more on this topic, see our guide to How Many Solar Panels for 1,750 kWh/Month?.
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What Does a Solar System for 800 kWh/Month Cost in 2026?
At recent national averages, a roughly 7.3 kW system costs about $20,700 to $22,100 before incentives. ConsumerAffairs reports an average of $2.84 per watt (typical range $2–$3), and SolarReviews reports an average of $3.03 per watt for a 7.2 kW system ($21,816). Individual quotes vary with state, roof complexity, equipment, and installer.
Estimated cost of a 7.3 kW system at different prices per watt
| Price per Watt | Estimated System Cost |
|---|---|
| $2.50 | $18,250 |
| $2.84 (ConsumerAffairs average) | $20,732 |
| $3.03 (SolarReviews average) | $22,119 |
| $3.50 | $25,550 |
Chart summary: Each $0.50 per watt changes the cost of a 7.3 kW system by about $3,650. Published national averages put the system near $21,000, but a quote at $3.50 per watt would cost about $4,800 more than one at $2.50. Price per watt is the fastest way to compare installers.
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
$52,500
Total solar cost (installed + remaining bills)
$21,000
Net savings
+$31,500
Avg. monthly difference
+$146/mo
Is There Still a Federal Solar Tax Credit in 2026?
For homeowners who buy with cash or a loan, no. The Section 25D Residential Clean Energy Credit applied through December 31, 2025, and the One Big Beautiful Bill Act, signed July 4, 2025, ended it after that date, as Solar.com and others report. See the IRS Residential Clean Energy Credit page for the official rules.
What may still help in 2026:
- Leases and power purchase agreements (PPAs): the installer or financier can claim the business 48E credit and may pass part of the benefit to you through lower payments. Terms vary, so compare total cost against buying.
- State and utility incentives: rebates, sales-tax exemptions, and property-tax exemptions exist in some places. Search DSIRE for your state.
- Net metering or net billing: how your utility credits exported power changes your savings. Some utilities, such as California’s net billing program, credit exports below the retail rate.
- Carryforward: if you placed a system in service in 2025 or earlier and have unused 25D credit, it may carry forward on your tax return. Ask a tax professional.
How Long Does It Take for Solar to Pay Back at 800 kWh/Month?
Payback is your net system cost divided by the electricity bill the system avoids, adjusted for rising rates and slow panel output decline. EIA’s Short-Term Energy Outlook puts the average U.S. residential price at 18.2 cents per kWh in 2026 and expects about 2% growth in 2027. For state-level payback data with the ITC applied, see our guide to Solar Panel Payback Period by State.
Our model uses a $21,000 system producing 9,600 kWh in year one, 18.2¢/kWh (about $1,747 saved in year one), 2% yearly rate growth, and 0.5% yearly panel output loss. It excludes financing costs, maintenance, and inverter replacement.
Modeled cumulative net cash flow, 7.3 kW system, no federal credit
| Year | Cumulative Net Position |
|---|---|
| 0 | −$21,000 |
| 1 | −$19,253 |
| 5 | −$12,000 |
| 10 | −$2,309 |
| 12 | +$1,773 |
| 15 | +$8,126 |
| 20 | +$19,362 |
| 25 | +$31,460 |
Chart summary: The line crosses zero between year 11 and year 12, so modeled break-even is about 11.1 years, and the modeled net position at year 25 is about +$31,500. Payback moves with your electricity rate: the same system pays back in about 16 years at 12 cents per kWh and about 7 years at 30 cents per kWh. If your utility pays less than the retail rate for exported power, payback will be longer; use our solar payback calculator with your own rate.
How to Lower Your Usage Before Sizing a Solar System
Each 100 kWh/month you remove cuts roughly 2–3 panels from the system at typical sun hours, so efficiency upgrades are often the cheapest “panels” you can buy. Good places to start:
- Heating and cooling: typically the largest share of home energy use. A properly sized heat pump, air sealing, and added insulation reduce it.
- Water heating: the U.S. Department of Energy notes heat pump water heaters are about two to three times as efficient as standard electric resistance models.
- Lighting: ENERGY STAR certified LEDs use at least 75% less energy than incandescent bulbs.
- Always-on loads: older refrigerators, spare freezers, and standby electronics add up. Smart power strips can trim some of it.
If your summer or winter months run far above 800 kWh, size to your 12-month average rather than your single highest month; oversizing for a peak adds cost without proportional savings in many utility markets. Check your utility’s net metering rules in DSIRE before choosing a size, and use our solar savings calculator to estimate bill savings.
How We Calculated These Numbers
- Sizing: annual kWh ÷ (peak sun hours × 365 × 0.80), panels = system kW ÷ 0.4 kW, rounded up.
- Sun hours: planning assumptions from 3.5 to 6.5 hours per day; your actual figure depends on location, tilt, orientation, and shade. Confirm with PVWatts.
- Cost: system size × price per watt, using published 2026 averages from ConsumerAffairs ($2.84/W) and SolarReviews ($3.03/W), plus a low and high case.
- Electricity rate: 18.2¢/kWh, EIA’s 2026 national residential average forecast. Rates vary widely by state.
- Payback model: 2% yearly rate growth and 0.5% yearly output loss; excludes financing, maintenance, inverter replacement, and incentives.
- Federal credit status: Section 25D ended December 31, 2025 (see the IRS and Solar.com links above).
This guide is general information, not tax, legal, or financial advice. Confirm incentives with your utility, state energy office, and a tax professional, and get multiple installer quotes before buying.
Frequently asked questions
Direct answers for US homeowners — sized for a $146/month electric bill.
Same usage, bill-based guide
Your 800 kWh/Month target maps to roughly a $125/month electric bill nationally.
$125 $125/month electric bill guidePopular state solar guides
Electricity rates and incentives vary — see data for your state.
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
- · 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.