How Long Do Solar Panels Last? What NREL and DOE Data Show

Solar panels last about 25 to 30 years, according to the U.S. Department of Energy (DOE), and they don’t stop working at the end of that. They slowly lose output instead: NREL research puts the median loss at about 0.5% a year, and a 2022 NREL fleet study found about 0.75% a year at the system level. The inverter, whose warranty is often much shorter, is more likely than the panels to need replacing along the way.

Here is what the federal data says about panel life, how much output you lose, and what the warranty actually covers, with the math shown so you can apply it to your own quote. If you’re planning a new roof too, see whether to replace your roof before solar.

The Short Answer: 25 to 30 Years, Then Lower Output

DOE says “Solar panels last about 25-30 years, which is similar to the lifetime of a roof” (DOE Solar Energy Technologies Office, July 28, 2021). Solar United Neighbors, a nonprofit that advises solar owners, uses the same range: panels “are built to last 25-30 years with minimal maintenance” (March 4, 2025).

That range is a planning figure, not an expiration date. NREL’s Solar Technical Assistance Team puts it plainly: “there are no end-dates per se.” After the warranty ends, “the level of actual output is no longer guaranteed,” and owners can repower, remove the system, or “leave it in place and let it continue to generate electricity, albeit at a lower level” (NREL, April 23, 2018).

How Fast Panels Lose Output

Panels lose a small share of their output every year, a process called degradation. Two NREL figures are the most useful:

Sources: NREL/PR-5200-56690 and NREL/PR-5K00-83487.

The first study pooled degradation rates reported in published studies; NREL’s 2012 slides say about 80% of reported rates were below 1% a year. The second measured whole systems in the field, which includes losses beyond the panels themselves, and DOE said in 2023 that its result was “representative of the entire U.S. PV fleet” (DOE, June 27, 2023). Neither study is limited to home rooftops, so treat 0.5% to 0.75% a year as a reasonable range, not a guarantee for your roof.

Where you live matters. NREL says degradation “could be higher in hotter climates and for rooftop systems,” and DOE reported that panels degrade more slowly in cooler climates.

What That Means in Kilowatt-Hours

NREL’s own example: at 0.5% a year, “in year 20, the module is producing approximately 90% of the electricity it produced in year 1.”

To see the effect over a system’s life, take an illustrative system that produces 10,000 kWh in its first year. Assume simple straight-line loss (year 1 at full output, each later year 0.5 or 0.75 percentage points lower) and no outages:

The gap is 7,500 kWh over 25 years. At the U.S. average residential price of 18.16 cents per kWh for August 2026 (EIA Electricity Monthly Update, preliminary), that is worth about $1,362, or roughly $54 a year. Your figure depends on your system size, rate and how your utility credits solar. Our solar payback guide shows how to build degradation into a payback estimate.

What Panel Warranties Cover

Panel quotes typically include up to three kinds of warranty:

• Product warranty: covers defects in the panel itself.
• Performance warranty: guarantees a minimum share of rated power over time.
• Workmanship warranty: from the installer, covering the installation. Solar United Neighbors describes it as a guarantee of “the quality of the installation.”

In 2018, NREL said “modules are typically warrantied for 20–25 years.” Newer warranties run longer. One example, from a March 2025 Qcells Q.TRON datasheet for a large-format module sold for both homes and commercial roofs:

By the same formula, the guarantee at 25 years works out to about 90.6% (our arithmetic: 98.5% minus 24 × 0.33). Warranty terms differ by manufacturer, model and country, so check the exact document named in your quote. Our guide to comparing solar quotes lists what to ask for.

A warranty is only as good as the company behind it. If the installer closes, manufacturer and workmanship warranties are affected differently; see what to do if your solar installer went out of business.

Inverters Usually Need Replacing First

The inverter turns the panels’ direct current (DC) into the alternating current (AC) your home uses. Solar United Neighbors says “Inverter warranties usually last 5-15 years,” well short of panel life. With warranties of 5 to 15 years, a string inverter may need replacing at least once over a panel’s life.

Microinverters, which sit under each panel, carry longer warranties. Enphase’s U.S. datasheet for the IQ8 series cites “an industry-leading limited warranty of up to 25 years” (Enphase IQ8SE datasheet, March 2022). Warranty length is not a lifespan guarantee, so read what the warranty covers. We compare warranty terms across models in our inverter and microinverter guide.

How to Get the Full Life Out of Your Panels

• Match the roof to the panels. If your roof has less than 25 to 30 years left, re-roofing first avoids paying later to remove and reinstall the array.
• Watch your monitoring app. A sudden drop in output is a fault, not normal degradation. Typical loss is under 1% a year.
• Keep the paperwork. Save the product, performance and workmanship warranties, the panel and inverter model numbers, and the installation date.
• Budget for the inverter. If you have a string inverter, plan for a replacement within the panels’ life.

Limitations

• The degradation studies are not limited to home rooftop systems. The 2022 fleet study covered mostly non-residential systems.
• NREL’s 0.5% figure comes from a literature review published in 2011 and NREL’s 2018 summary; newer panels may perform differently, in either direction.
• The kWh and dollar example is illustrative, uses straight-line loss and a single national average price, and ignores outages, rate changes and inverter replacement costs.
• The Qcells terms are one manufacturer’s datasheet, not a market average.

Sources and Verification

Checked Nov. 4, 2026.