- Payback depends mainly on four numbers: system price, local sunshine, your electricity rate, and what your utility pays for exported power.
- US residential electricity averaged about 17.3 cents per kWh in 2025, according to EIA, but local rates range from well under that to more than double.
- Panels typically lose about 0.5% of output per year (NREL), and module warranties commonly run 20 to 25 years.
- The US homeowner solar tax credit (25D) ended for systems installed after 2025, which lengthens payback for owned systems.
The payback formula
Simple payback is:
Net system cost ÷ first-year bill savings = years to break even
Net cost is the price after any rebates or incentives you actually qualify for. First-year savings depend on how much of the solar output you use directly (which avoids buying power at your full retail rate) and how much you export (credited at whatever your utility pays). A payback well inside the panels' expected life, roughly 25 years or more, means the system should more than pay for itself.
Worked example: one house, three scenarios
Take an 8 kW system in a location where each kW produces about 1,300 kWh a year, giving 10,400 kWh in year one. The household pays 18 cents per kWh.
Scenario A: median price, full retail net metering
- Cost: 8,000 W × $3.60/W = $28,800
- Savings: 10,400 kWh × $0.18 = $1,872 a year
- Payback: $28,800 ÷ $1,872 = 15.4 years
Scenario B: cash price, full retail net metering
- Cost: 8,000 W × $3.00/W = $24,000
- Savings: $1,872 a year
- Payback: $24,000 ÷ $1,872 = 12.8 years
Scenario C: median price, low export rate
Now assume the home uses 60% of the output directly and exports 40% at 6 cents per kWh.
- Used on site: 6,240 kWh × $0.18 = $1,123
- Exported: 4,160 kWh × $0.06 = $250
- Savings: $1,373 a year
- Payback: $28,800 ÷ $1,373 = 21.0 years
Same roof, same panels, and the payback ranges from under 13 years to 21. The price you negotiate and the export rules you live under matter as much as the sunshine.
The factors that move payback most
| Factor | Helps payback | Hurts payback |
|---|---|---|
| Electricity rate | High retail rates (25¢+ per kWh) | Cheap power (under 12¢ per kWh) |
| Export compensation | Full retail net metering | Low avoided-cost or wholesale export rates |
| Sunshine and roof | Unshaded south- or west-facing roof in a sunny region | Heavy shade, north-facing or cloudy climate |
| Installed price | Cash price near or below the local median | Financed price with dealer fees, or complex roof work |
| Incentives | State, utility or local rebates you qualify for | None available |
| Usage pattern | High daytime use (home office, pool pump, EV charging during the day) | Most use at night with low export rates |
When solar is a strong, marginal or weak bet
Strong case
High electricity rates, good sun, a roof that will last another 20 years, retail or near-retail credit for exports, and a fair cash or low-cost financed price. Paybacks under about 10 years are common in this situation.
Marginal case
Average rates and sunshine, partial export credit, and no remaining incentives. Payback lands in the mid-teens. Solar still likely pays off over its life, but the return is modest, and how long you stay in the house becomes important.
Weak case
Cheap power, a shaded or north-facing roof, a roof that will need replacing in a few years, or a financed price well above the local median. Payback can stretch past 20 years. Look instead at community solar or cheaper efficiency upgrades that cut usage first.
Costs that payback calculations often miss
- Inverter replacement. String inverters often have shorter warranties than panels; budget for one replacement over the system's life unless the warranty covers it.
- Roof work. Removing and reinstalling panels for a new roof costs money. Reroof first if your roof is near the end of its life.
- Fixed utility charges. Solar cannot offset monthly customer charges or minimum bills.
- Financing costs. Interest and dealer fees can add thousands. Compare options in our lease vs loan vs cash guide.
- Insurance and property tax. Check whether your policy premium changes and whether your state exempts solar from property tax assessment.
Beyond payback: other ways to judge the deal
Cost per kWh produced. Divide the net price by expected lifetime output. If that figure is well below what you pay the utility, solar is a good hedge. Our solar cost guide shows the arithmetic.
Return versus alternatives. A 12-year payback is roughly comparable to an 8% simple annual return on the upfront cost. That return is not guaranteed and it shrinks if output, rates or export rules change.
Home value. Owned systems may add value at resale, but leased systems can complicate a sale. Do not count on a specific premium.
Resilience. Standard grid-tied solar shuts off during a power cut for safety. Backup requires a battery or a specific inverter setup; see our home battery guide.
A five-step decision process
- Find your real marginal electricity rate (energy charges per kWh, not the fixed fees) from a recent bill.
- Check your utility's current export rules. Our net metering explainer covers the main types.
- Estimate output with our solar savings calculator or NREL PVWatts.
- Get real local prices. You can request a few free installer quotes to replace assumptions with numbers.
- Run payback using the net price after the incentives you actually qualify for. If it beats roughly 15 years and you plan to stay, solar is usually worth serious consideration.
Frequently asked questions
What is a good payback period for solar?
Anything under about 10 years is strong. 10 to 15 years is reasonable for a system expected to last 25 years or more. Beyond 20 years, the investment case is thin unless you value other benefits such as backup power or emissions cuts.
Are solar panels worth it without the federal tax credit?
In many places, yes, especially with high electricity rates and fair cash prices. Losing the credit lengthens payback, so the case is weaker in areas with cheap power or poor export compensation. Run the numbers for your home.
Is solar worth it if I might move in five years?
It depends on your market. An owned system may add value, but you are unlikely to recoup the full cost in five years from savings alone. Leased systems need to be transferred to the buyer, which can complicate a sale.
Should I make efficiency upgrades before going solar?
Usually yes. Cutting waste first, through LED lighting, air sealing or a smarter thermostat, means you can buy a smaller, cheaper system. Start with our guide to lowering your electric bill.
Run your own numbers
Plug your bill, prices and climate into our free solar savings calculator — every assumption is editable.
This guide is general information, not financial, tax or engineering advice. Prices and incentives change — confirm with qualified local professionals and official program sources. See our methodology and disclosures.