The Tri-State Area’s Top Solar Installers
If you are trying to figure out how to fix underproducing solar panels out of warranty, I want you to know the situation is almost never as bad as it feels. Every year, I take calls from many homeowners who assume a drop in solar output means a whole system replacement.
In my experience, it almost never does. Most fixes vary, and the process for finding the problem is the same one our qualified solar technicians use on every service call. I will walk you through it here.
To fix underproducing solar panels out of warranty, confirm the drop in your monitoring app year over year — healthy panels lose only about 0.5% annually (NREL), so a 10 to 20% decline is a fixable fault.
Rule out soiling, new shading, and a tripped breaker, then check every warranty layer, since manufacturer coverage survives even if your installer closed. Roughly 80% of failures are inverter-related (kWh Analytics), and most repairs cost $150 to $3,000, not a new system.
TerraSol Energies, NABCEP-certified and serving southeastern Pennsylvania, Delaware, New Jersey, and Maryland since 2009, repairs out-of-warranty and orphaned systems.
Start with your monitoring system!
Before you spend a dollar on a repair service, confirm the problem is real. Solar power naturally rises and falls with the seasons, and I have visited plenty of customers who were worried about a “failing” solar array in December that was performing exactly as designed.
Research from the National Renewable Energy Laboratory (NREL) shows crystalline silicon solar panels lose a median of about 0.5% of energy output per year. That is normal long-term degradation.
A healthy 10-year-old system should still produce roughly 95% of its rated capacity. What is not normal is a noticeable drop of 10 to 20% compared to the same month in previous years. That points to a fixable solar panel problem.
Here is what I tell customers to look for in their monitoring app:
Compare year over year. Check this June against last June, not June against December. Seasonal swings in energy production across the tri-state area are big.
Look at the shape of the decline. A slow, steady slide in solar output usually means soiling or tree growth. A sudden drop, or zero production on sunny days, usually means an inverter or wiring fault.
Check panel-level data if you have it. Systems with microinverters or power optimizers show per-panel performance, which makes it easy to spot one or two damaged solar panels versus a system-wide issue. This is one reason we install Enphase equipment as an Enphase Gold Installer.
Rob’s tip: One of my favorite parts of this job is revisiting customers a year after installation. The homeowners who know their monitoring system inside and out catch performance issues within days, not months.
Five minutes a week in the app is the cheapest insurance your solar equipment will ever get. It is the same habit that keeps a zero energy certified school we monitor running at peak efficiency.
Not sure what your monitoring app is telling you? Send us a screenshot of your production data, and we will tell you whether the drop is seasonal or a real fault. Call us at (888) 873-9995!
The inverter converts the DC electricity your panels produce into the AC power your home uses, and it is the hardest-working of all the key components in your system. Research from kWh Analytics has found that roughly 80% of solar array failures and downtime are inverter-related.
String inverters typically last 10 to 15 years, which is shorter than the life of the panels, so on an out-of-warranty system, the inverter is always my first suspect.
Warning signs include error codes, a red or orange status light, zero production on sunny days, or a unit that keeps restarting. When a string inverter fails, the whole system goes down at once, which is actually helpful for diagnosis: total loss of power almost always means inverter or electrical, not the panels.
Dust, pollen, leaf debris, and bird droppings block sunlight and reduce output. In Chester and Delaware County, spring pollen season is the worst offender I see, followed by fall leaf drop.
Soiling builds gradually, which is why it hides in the data until you compare across seasons. Rain clears most of it, but stubborn buildup like bird droppings needs a proper cleaning. Never use harsh chemicals or a pressure washer on panels; both can damage the glass and coatings.
Trees grow, and system design that was perfect on installation day can be compromised ten years later. Tree branches that cleared your roof line in 2015 may shade your solar array for hours a day now. Because cells inside a panel are wired in series, even partial shading causes a disproportionate loss.
On a string inverter system, one shaded panel can drag down an entire string. I have seen trimming two branches recover more electricity than any repair on the truck that day.
And when trimming is not an option, rethinking the layout can work instead. One Chester County homeowner solved it with a creative mounting solution after replacing his roof.
Individual panels can develop hot spots, damaged cells, cracked glass from falling debris or weather damage, and moisture intrusion through failed seals.
Wiring degrades too: corroded or damaged connectors, rodent-chewed cables, wiring errors from the original solar installation, and loose connections at the junction box all reduce output. Some of these faults also create a real fire risk, which is why anything involving DC wiring belongs with a qualified solar technician, not a ladder and good intentions.
Sometimes the system is fine, and the original production estimate was optimistic. If your panels are 15 to 20 years old and producing 88 to 92% of day-one output, that matches NREL’s median degradation data. The honest answer there is not a repair; it is adjusting expectations or adding capacity.
Expanding an older system is more common than you might think. We recently added energy storage to an existing system in Delaware County. And if you are a PECO customer thinking about more panels, the utility’s residential solar rebate can offset part of the cost.
Seeing an error code or zero production on a sunny day? That is the one symptom worth calling about today, because every day of downtime is kilowatt-hours you are buying back from PECO at 2026 rates. Call (888) 873-9995 for a same-week inverter diagnosis.
Before booking a professional inspection, run these free checks from the ground:
Read the inverter display or app. Write down any error codes and look them up in the manufacturer’s documentation. Many codes point straight to the fault.
Check your circuit breakers. A tripped solar breaker in your main panel or AC disconnect will silently zero out production. I have driven an hour to flip a breaker. More than once.
Restart the system. Follow the shutdown and restart sequence in your owner’s manual. Inverters are computers, and computers sometimes need a reboot.
Inspect visually from the ground. Use binoculars to look for heavy soiling, debris, new shading, or visible solar panel damage. Do not climb on the roof.
Check your electric bill and net metering credits. A shrinking credit is often the first clue homeowners notice, sometimes before they open the monitoring app.
⚠ Safety warning: Do not open the inverter, do not touch DC wiring, and do not spray water on hot panels. A solar array carries lethal DC voltage whenever the sun is up.
Out of warranty does not mean unaffordable. And with PECO raising electric rates this year, every lost kilowatt-hour costs you more on your electric bill than it did last year. Typical 2026 residential price ranges:
| Service | Typical 2026 Cost | When It Applies |
|---|---|---|
| Professional cleaning | $150 – $500 | Gradual decline from soiling |
| Inspection & diagnosis | $150 – $300 | Cause unclear; often credited toward repair |
| String inverter replacement | $1,100 – $3,000 | Sudden or total production loss, unit 10+ years old |
| Single microinverter swap | A few hundred dollars | One panel underperforming |
| Panel replacement | Varies by brand | Cracked glass, hot spots, damaged cells |
| Tree trimming | Varies | New shading; often the highest-return fix |
NOTE: These numbers are all estimated. So better talk to our experts to get an exact quote.
My honest take on the biggest decision: if your string inverter dies at year 12 to 15, seriously consider replacing it with microinverters instead of another string unit.
You gain panel-level monitoring and remove the single point of failure, and new microinverters commonly carry 25-year manufacturer warranties, far longer than the component they replace. Inverters typically fail before panels do, so this is the one upgrade that changes the long-term math. It also opens the door to adding battery storage down the road.
Two more avenues people forget. First, homeowners insurance: sudden events like storm damage or falling tree branches are often covered perils, so a weather-related loss may be an insurance claim rather than an out-of-pocket repair.
Check your policy before paying cash. Second, some causes of underproduction have nothing to do with broken solar equipment at all, and cleaning or trimming solves them for a few hundred dollars.
This is the step I see skipped most often. “Out of warranty” usually means one warranty expired, not all of them. One caveat first: if you lease rather than own, repairs are usually the leasing company’s responsibility, a difference I broke down in my ownership vs lease comparison.
It matters at resale too, when buyers start asking about buying out a solar lease. For owned solar systems, warranty coverage comes in layers that expire on different clocks:| Warranty Layer | Typical Length | What It Covers |
|---|---|---|
| Panel performance | 25 years | Guarantees roughly 80 to 85% of rated output at year 25 |
| Panel product | 10 – 25 years | Manufacturing defects in the panel itself |
| String inverter | 10 – 12 years | The inverter unit |
| Microinverter | Often 25 years | Each microinverter unit |
| Installer workmanship | 5 – 10 years | The installation labor |
Call a solar company when you have confirmed a real drop in system performance and the cause is not obvious soiling, when your inverter shows persistent error codes, when you suspect solar panel damage or wiring faults, or any time the fix involves the roof or the inside of electrical equipment.
When you are choosing a repair service for an out-of-warranty system, ask four questions. Does the company service solar systems it did not install? Not every solar installer will. Are the technicians certified on your equipment brand?
Will you get a written diagnostic report with production data? And does the repair itself come with a workmanship guarantee? A solar company with a good reputation will answer yes to all four without hesitation.
Credentials are worth checking too; our own team holds NABCEP certification, the most rigorous credential in the solar industry.
At TerraSol Energies, we service systems across southeastern Pennsylvania, Delaware, New Jersey, and Maryland, including systems whose original company that installed them is long gone.
If your production numbers do not look right, call us at (888) 873-9995 or reach out through our Solar Maintenance page, and we will take a look.
Call a solar company when you have confirmed a real drop in system performance and the cause is not obvious soiling, when your inverter shows persistent error codes, when you suspect solar panel damage or wiring faults, or any time the fix involves the roof or the inside of electrical equipment.
When you are choosing a repair service for an out-of-warranty system, ask four questions. Does the company service solar systems it did not install? Not every solar installer will. Are the technicians certified on your equipment brand?
Will you get a written diagnostic report with production data? And does the repair itself come with a workmanship guarantee? A solar company with a good reputation will answer yes to all four without hesitation.
Credentials are worth checking too; our own team holds NABCEP certification, the most rigorous credential in the solar industry.
At TerraSol Energies, we service systems across southeastern Pennsylvania, Delaware, New Jersey, and Maryland, including systems whose original company that installed them is long gone.
If your production numbers do not look right, call us at (888) 873-9995 or reach out through our Solar Maintenance page, and we will take a look.
Healthy panels lose only about 0.5% of output per year (NREL median), so a 10 to 20% drop versus the same month last year signals a fixable problem, not normal aging.
Roughly 80% of solar array failures and downtime are inverter-related (kWh Analytics), and string inverters usually fail years before the panels do.
“Out of warranty” often is not: panel, inverter, and workmanship warranties expire on different clocks, and manufacturer warranties survive even if your installer went out of business.
Repairing an older system is almost always worth it, because owned solar keeps paying for itself long after warranties lapse. The economics of solar power in our region still work, as I argued when the federal tax incentive ended.
Confirm the drop in your monitoring app, rule out the simple stuff, check every warranty layer before you pay, and bring in a certified technician for anything electrical.
Learning how to fix underproducing solar panels out of warranty really comes down to those four steps, and after all the service calls TerraSol Energies has run since 2009, I can tell you they solve the problem far more often than a new system does.
The most common causes are inverter failure, soiling from dirt and bird droppings, new tree growth causing shading, wiring faults, and normal aging. Panels typically lose only about 0.5% of output per year, so a drop of 10% or more versus the same month in prior years signals a fixable problem, not normal degradation.
Most out-of-warranty repair costs fall between $150 and $3,000. Professional cleaning runs $150 to $500, inspections $150 to $300, and a full string inverter replacement roughly $1,100 to $3,000 installed. Swapping a single failed microinverter or fixing loose connections typically costs a few hundred dollars.
Yes. Manufacturer warranties on panels and inverters remain valid even if your installer closes. A licensed solar company can file those warranty claims for you and perform the repair, and you typically pay only labor. Fully out-of-warranty solar equipment can be repaired by any qualified solar technician.
Usually, yes. Panels routinely outlast their original inverter, since string inverters last 10 to 15 years while panels carry 25-year performance warranties. If your panels still produce well, a new inverter restores full energy output for a fraction of the cost of a new solar installation, and modern replacements carry longer warranties than the original.
TerraSol Energies, Inc. develops and manages turnkey solar solutions that provide renewable energy means for homeowners, business owners, and non-profits.
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