Solar System Not Producing Enough? Your Rights and How to Get Compensated

First: Is It Actually Underperforming, or Just Normal Variation?

Before anything else, confirm the shortfall is real. Solar output naturally swings with the seasons — far lower in short, cloudy winter months than in long summer days — and a single weak month proves nothing. The benchmark that matters is the annual comparison against what you were promised. A useful rule of thumb: if your production runs consistently 20% or more below your estimated or guaranteed output across several months, that is enough to treat as a real problem rather than seasonal noise. The U.S. Department of Energy publishes regional output benchmarks you can use to sanity-check whether your shortfall is genuine or just how solar behaves where you live.

Start with your monitoring app or portal and compare actual production to the guaranteed or estimated figure in your contract. If you are consistently and significantly under, you have a documented shortfall worth pursuing. If it flatlines to zero during sunny daylight hours, that is not underperformance — that is a system that is down, and the first move is checking your breaker and calling your installer.

Why a Solar System Is Not Producing Enough

When a solar system is not producing enough energy, the shortfall has a cause, and identifying yours points you to the right remedy. The common culprits fall into a few groups:

Equipment and Installation Problems

• Inverter failure — inverters typically last 10 to 15 years, shorter than the panels, and a failing inverter can crater or zero out production. This is one of the most common causes.
• Wiring and connection faults — loose connections, voltage drops, or ground and arc faults that quietly bleed output.
• Panel defects or accelerated degradation — panels losing more than about 1% per year (after weather correction) are degrading abnormally, which can be a valid warranty claim.

Design and Sales Problems

• Incorrect system sizing — a system designed too small for the home, often because the sales projection was optimistic rather than accurate.
• Unrealistic production estimates — a projection that overstated what your roof, orientation, and shading could ever deliver. This is where underperformance shades into misrepresentation.
• Unaddressed shading — trees or structures the installer should have accounted for but did not, especially damaging in string-inverter systems where one shaded panel drags down a whole string.

Maintenance Problems

Dirty panels, debris, and blocked airflow can reduce output by 5% to 25% in dusty regions — real, but usually a maintenance fix rather than a legal claim. Ruling these out first strengthens any claim you do bring, because it removes the installer’s easiest excuse.

The Three Guarantees — and Which One Covers Your Shortfall

“Solar warranty” is not one thing, and knowing which guarantee applies is what makes a claim succeed. Underperformance can touch three different promises, each with a different payer and remedy.

The Production Guarantee (the one that pays cash)

A production guarantee is a promise from the installer about the actual kilowatt-hours your specific system will generate each year, based on your location, orientation, shading, and roof. It is the strongest protection against underperformance because it pays regardless of the cause: if your system produces less than guaranteed, the installer typically compensates you at roughly $0.10 to $0.20 per missing kilowatt-hour. Not every contract includes one — but if yours does, it is usually your most direct route to money.

The Performance Warranty (the manufacturer’s degradation promise)

The performance warranty, from the panel manufacturer, guarantees a minimum percentage of rated output over time — commonly around 80% to 92% at year 25, with degradation capped near 0.5% per year. If your panels drop below the warranted curve and you can document it, the manufacturer must repair, replace, or compensate. In practice these are longer-term and harder to enforce, but abnormal early degradation is a legitimate claim.

The Workmanship Warranty (the installer’s labor promise)

The workmanship warranty covers installation faults — the wiring, the connections, the setup — that suppress production. Where bad installation is the cause, this is the promise you invoke, and it overlaps with the same installer-liability principles covered in our guide to solar-related roof and installation damage.

Warranty Claim vs. Misrepresentation: The Distinction That Changes Everything

This is the fork that determines what kind of case you have, and it is worth getting right. If your system underperforms because something broke or was installed poorly, that is a warranty or production-guarantee claim — you want the system fixed or the shortfall compensated. But if the system is working as well as it ever could and the problem is that you were sold a number it was never capable of hitting, that is a misrepresentation claim — a different and often more powerful theory. Being sold a system that is now not producing what was promised is not the same as owning one that broke, and that distinction decides your path.

The tell is whether the shortfall traces to a fixable defect or to an estimate that was inflated from the start. A projection built on ignored shading, an oversized promise, or savings math that quietly assumed rates that no longer applied is not an equipment problem — it is a sales problem. When that is the case, the shortfall can support a deceptive-practices or solar fraud claim, and the remedy can reach beyond the production gap to canceling the contract or challenging the financing. If your savings never appeared largely because of changed net-metering rules rather than the hardware, that specific dynamic is covered in our guide to broken solar savings promises. An attorney can tell you which side of this line your situation falls on — and often, a strong case pleads both.

How Much of a Shortfall Justifies a Claim?

Homeowners often wonder how far below the promise their production has to fall before it is worth acting. There is no single legal number, but a few practical benchmarks help you judge whether you have a real case or a minor variance.

The 20% rule of thumb. Production running 20% or more below your estimate across several months is widely treated as the threshold that justifies a formal complaint rather than waiting it out. Below that, seasonal and weather variation can plausibly explain the gap; at or above it, something is usually wrong.

The degradation curve. For an older system, compare year-over-year output. Losing more than about 1% per year after weather correction is faster than normal aging and points to a defect or a warranty breach rather than expected wear.

The guarantee threshold. If your contract has a production guarantee, the number in that clause is your bright line: any output below it is a breach by definition, regardless of how small the gap looks. A guarantee turns a fuzzy “is this bad enough?” question into a clear yes or no.

The larger and more sustained the shortfall, the stronger the claim, but even a modest, consistent gap against a written guarantee is actionable. When in doubt, a full year of monitoring data compared against your promised figure settles the question quickly.

What Your Underperformance Is Actually Costing You

When your panels are producing less than estimated, the shortfall is not abstract — it has a dollar value, and quantifying it is the foundation of any claim or demand. The losses typically include:

• Lost electricity value — the missing kilowatt-hours multiplied by your utility’s rate per kWh.
• Extra utility costs — the power you now have to buy from the grid to cover what the system was supposed to produce.
• Diminished system and home value — a system that does not meet its guarantees is worth less, which can affect resale.
• Investigation costs — an independent performance assessment to prove the shortfall.

These damages keep accruing every month the system underproduces, which is a point worth making in any demand: the number is not static, it grows until the system is fixed or the claim is resolved.

How to Document and Pursue a Solar Production Claim

Production claims live or die on documentation. Follow these steps in order.

1. Pull 12 months of monitoring data. Comprehensive production records — ideally a full year — are what prove a shortfall against an annual guarantee. Continuous monitoring is your evidence; start capturing it now if you have not been.

2. Find your promised number. Locate the exact production estimate or guarantee in your contract or the savings sheet you were shown. The gap between that figure and your actual output is your claim.

3. Rule out the simple causes. Clean the panels, confirm no new shading, and check the breaker and inverter status. Eliminating maintenance issues removes the installer’s easiest defense.

4. Get an independent performance assessment. A neutral solar professional documenting the cause and the shortfall is the backbone of a contested claim.

5. Send a written demand referencing your guarantee. A formal letter that cites the production guarantee or warranty, attaches your data, quantifies the damages, and demands a specific remedy — repair, upgrade, or compensation — within a set deadline, typically 30 days.

6. Escalate if ignored. A complaint to your state attorney general or contractor licensing board, and a solar fraud attorney’s involvement, are what move an unresponsive installer. Repeated repair visits that never fix the problem are themselves grounds to escalate toward cancellation.

Matching Your Situation to the Right Remedy

Different underperformance situations call for different first moves. In broad terms:

• Producing less than guaranteed — file the production-guarantee claim first; it is the most direct route to compensation.
• Panels never activated or interconnected — this is non-performance, and it supports demanding cancellation, not just a repair.
• Repeated repair visits with no fix — a pattern of failed repairs escalates toward full contract cancellation.
• Installer unresponsive — document everything and bring in an attorney; silence is a common tactic, not a dead end.
• Sold on numbers it could never hit — that is misrepresentation, and the remedy can reach the whole contract.

Frequently Asked Questions

How do I know if my solar system is not producing enough, or if it’s just normal variation?

Compare a full year of actual production against your guaranteed or estimated output, not a single month, since solar swings seasonally. A useful threshold is 20% or more below estimate across several months, which is enough to treat as a real problem. Zero production during sunny daylight, by contrast, means the system is down, not underperforming.

What is a solar production guarantee and how does it pay?

A production guarantee is the installer’s promise about the actual kilowatt-hours your system will generate annually. If it produces less than guaranteed, the installer typically compensates you at roughly $0.10 to $0.20 per missing kilowatt-hour, regardless of the cause. Not every contract includes one, so check yours, it is often the most direct route to compensation.

What’s the difference between a production guarantee and a performance warranty?

A production guarantee comes from the installer and promises a specific annual energy output for your system, paying cash for shortfalls. A performance warranty comes from the panel manufacturer and guarantees a minimum percentage of rated output over time (commonly 80-92% at year 25), remedied by repair, replacement, or compensation. They cover different promises and are enforced against different parties.

Can I sue if my solar panels produce less than promised?

Possibly, and which claim depends on the cause. If a defect or bad installation is the problem, it is a warranty or production-guarantee claim. If the system works as well as it ever could but you were sold an inflated number, it may be a misrepresentation claim, which can reach the whole contract. An attorney can identify which applies and whether both do.

My installer won’t respond to my underperformance complaint. What now?

Document everything in writing, send a formal demand with your monitoring data and original production estimate, and keep proof of delivery. If the installer stays silent, file a complaint with your state attorney general or contractor licensing board and involve a solar attorney. Unresponsiveness is a common tactic, and an attorney demand often breaks the silence.

Can I cancel my solar contract if the system doesn’t produce enough?

Sometimes. A system that was never activated or interconnected supports demanding cancellation for non-performance. Repeated failed repairs can also escalate toward cancellation. And where the shortfall traces to misrepresentation in the sale, cancellation or rescission of the financing may be on the table alongside the production claim.

What documentation do I need for a solar production claim?

At minimum, twelve months of monitoring data showing actual output, the promised production figure from your contract or savings sheet, records showing you ruled out dirty panels and shading, and ideally an independent performance assessment. Comprehensive documentation is what turns a complaint into a claim that gets paid.

What if my solar company went out of business before fixing the underperformance?

You may still have recourse. Manufacturer performance warranties survive the installer, a contractor bond may respond, and if a lender financed the system, the FTC Holder Rule may let you raise the installer’s conduct against the finance company. The company’s failure changes how you pursue the claim but does not erase it.

Sold a System That Never Delivered? Find Out What You’re Owed.

If your solar system is producing far less than you were promised, the shortfall has a real dollar value — and depending on the cause, the installer may owe you compensation, a fix, or more. Homeowners with questions about an underperforming solar system can request a free case review. Credible Law connects homeowners nationwide with independent, licensed attorneys who handle defective and underperforming solar systems, production-guarantee disputes, and contract cancellation. An attorney can review your production data against what you were promised and tell you whether you have a case. There is no cost to be matched with counsel.

Credible Law is a national legal resource and attorney referral network, not a law firm, and does not provide legal advice or representation. This article is for educational purposes only and does not create an attorney–client relationship. Production guarantees, warranty terms, and available remedies depend on your contract, your equipment, and your state; consult a licensed attorney and review your specific warranty documents. Information is current as of September 2026.