Solar Panel Calculator
Find out how many solar panels your home needs, what the system costs, and how long it takes to pay back. Uses NREL peak sun-hour data and EIA electricity rates for all 50 states — and 2026 federal tax credit rules, which changed.
How much of your usage the system should cover.
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US average ~$2.75/W installed (range $2.50–$3.50).
NREL PVWatts default is 14%.
Federal credit is $0 in 2026 — see note below.
Your Solar Estimate
Savings assumption: every kWh produced is valued at your full retail rate. That holds under 1:1 net metering or for power you use as it is generated. Under net-billing tariffs (California NEM 3.0 and similar), exported power earns far less than retail, so real savings can be materially lower.
How Solar Production Is Calculated
System losses cover soiling, wiring, inverter conversion, panel mismatch and temperature effects. The calculator defaults to 14%, which is the NREL PVWatts standard assumption.
Where Solar Pays Back Fastest
Sun alone does not decide the economics — the price of the electricity you avoid matters just as much. This ranks selected states by the annual bill savings each installed kW generates:
| State | Sun Hrs/Day | Rate (¢/kWh) | kWh/yr per kW | Savings/yr per kW |
|---|---|---|---|---|
| California | 6.08 | 34.74 | 1,909 | $663 |
| Massachusetts | 4.7 | 29.61 | 1,475 | $437 |
| New York | 4.5 | 29.49 | 1,413 | $417 |
| Arizona | 6.54 | 15.18 | 2,053 | $312 |
| Nevada | 6.41 | 13.11 | 2,012 | $264 |
| Texas | 5.22 | 15.94 | 1,639 | $261 |
| Florida | 5.48 | 15.1 | 1,720 | $260 |
| Louisiana | 5.32 | 13.49 | 1,670 | $225 |
| Washington | 3.95 | 14.91 | 1,240 | $185 |
Notice Nevada and Louisiana: excellent sun, but cheap power means each installed kW saves far less per year than in Massachusetts or New York, which get roughly a third less sunlight. High electricity prices, not sunshine, are the strongest predictor of a fast solar payback.
Frequently Asked Questions
How many solar panels do I need for my house?
Divide your annual electricity usage (kWh) by the annual production of 1 kW of panels in your state, then divide the resulting system size by your panel wattage. In Arizona, 1 kW produces about 2,053 kWh/year (6.54 peak sun hours × 365 × 0.86 after losses), so a 12,000 kWh/year home needs about 5.8 kW — roughly 15 panels at 400 W each. In New York, where 1 kW makes only about 1,413 kWh/year, the same home needs about 8.5 kW, or 22 panels.
Is there a federal solar tax credit in 2026?
No, not for a cash or loan purchase. The 30% residential clean energy credit (Section 25D) expired on 31 December 2025 under the One Big Beautiful Bill Act, with no phase-down and no partial credit — systems installed in 2026 receive $0 federal credit. The commercial credit (Section 48E) remains available for eligible projects, and third-party ownership via a lease or PPA can still route federal incentives through the installer. Many solar calculators still apply the old 30% and will understate your true out-of-pocket cost.
How much do solar panels cost in 2026?
Residential solar averages roughly $2.50–$3.50 per watt installed in 2026, with about $2.75/W as a national midpoint per NREL and EnergySage data. That puts a typical 6 kW system near $16,500 gross. Panels themselves are only 25–35% of the price — the rest is inverters, racking, labor, permits, and interconnection.
What is a peak sun hour?
A peak sun hour is one hour of sunlight at 1,000 watts per square meter — the standard test intensity for solar panels. It is not the same as daylight hours. A state averaging 5 peak sun hours per day may have 12 hours of daylight; the figure compresses total daily solar energy into equivalent full-intensity hours, which makes production math simple: kWh per year = system kW × peak sun hours × 365 × efficiency factor.
What is a realistic solar payback period?
Payback is net system cost divided by annual bill savings, and it swings hard on two variables: local sun and local electricity price. Expensive-power states with decent sun (California at 34.7¢/kWh, Massachusetts at 29.6¢/kWh) pay back fastest. Cheap-power states (Nevada at 13.1¢/kWh, Louisiana at 13.5¢/kWh) take considerably longer despite good sun, because each offset kWh is worth less. Losing the 30% federal credit in 2026 adds roughly 3–5 years to a typical payback versus a 2025 install.
Does net metering affect these savings numbers?
Yes, significantly. This calculator values every kWh you produce at your full retail electricity rate, which is accurate under traditional 1:1 net metering or for power you consume directly as it is generated. Many states have moved to net billing instead — California's NEM 3.0, for example, credits exported power at avoided-cost rates roughly 70-75% below retail. If you are on a net-billing tariff and export a large share of your production, your real savings and payback will be meaningfully worse than shown, unless you add a battery to consume more of your own generation. Check your utility's current export compensation rules before committing.
Do solar panels still make sense without the federal tax credit?
It depends heavily on your state. In high-rate states the savings still outrun the cost comfortably over a 25-year panel warranty, especially with utility rates rising a few percent per year. In low-rate states with average sun, payback can now stretch past 15 years, which is a much weaker case. Run your own numbers above with your actual bill and check your state's incentive programs, net metering rules, and any utility rebates before deciding.