Why Is My Solar System Underperforming? A Homeowner's Guide
Why Is My Solar System Underperforming? A Homeowner’s Guide
One of the most frustrating things a homeowner can experience is discovering that their solar system isn’t producing as much electricity as it used to. Maybe your electric bill has gradually increased, your monitoring app is showing lower production than expected, or you’ve noticed your system simply isn’t offsetting your energy usage the way it once did.
The first question most people ask is, “Is something broken?”
Sometimes the answer is yes—but often, it isn’t.
An underperforming solar system doesn’t always mean you have a major equipment failure. In many cases, the cause is something relatively simple, such as dirty solar panels, increased shade from a growing tree, bird nests beneath the array, or a tripped breaker. Other times, the issue is electrical and requires professional troubleshooting to identify.
The important thing to remember is that “underperforming” isn’t a diagnosis—it’s a symptom. The goal is to identify the specific reason your system isn’t producing as expected instead of replacing parts or making repairs based on guesswork.
This guide walks through the most common reasons solar systems lose production, what homeowners can safely check themselves, and when it’s time to schedule a professional solar diagnostic inspection.
What Does “Underperforming” Actually Mean?
Every solar system naturally produces different amounts of electricity throughout the year.
Production changes based on:
The season
Daylight hours
Cloud cover
Temperature
Weather conditions
Household energy usage
Because of these natural fluctuations, many homeowners mistake normal seasonal changes for equipment problems.
A system is generally considered underperforming when it’s producing significantly less electricity than expected under similar weather conditions.
Examples include:
Lower production than the same month last year.
Lower production than neighboring systems with similar layouts.
A gradual decline that continues over several weeks or months.
A sudden drop in daily production.
Increased utility bills despite similar energy usage.
Alerts or error messages in the monitoring app.
Understanding whether the drop was gradual or sudden is often one of the biggest clues to identifying the underlying problem.
Step 1: Has Anything Around Your Home Changed?
Before assuming something inside the solar system has failed, take a look around your property.
Many production problems have nothing to do with the electrical equipment itself.
Ask yourself:
Have nearby trees grown taller?
Was new construction recently completed nearby?
Are there new structures creating shade?
Have birds started nesting beneath the panels?
Are leaves or branches covering part of the array?
Are the panels visibly dirty?
Even relatively small changes can reduce the amount of sunlight reaching your solar panels.
Unlike electrical failures, these issues are often visible without specialized testing equipment.
If you notice new shade that wasn’t present a year ago, trimming vegetation may restore much of your system’s performance.
Step 2: Check for Dirty Solar Panels
One of the easiest—and most commonly overlooked—causes of reduced solar production is dirty panels.
Over time, your solar array collects:
Dust
Dirt
Pollen
Bird droppings
Leaves
Smoke residue
Tree sap
Hard water spots
This buildup is known as solar panel soiling, and it reduces the amount of sunlight reaching the photovoltaic cells.
The production loss is usually gradual, making it difficult to notice day to day.
If your panels haven’t been professionally cleaned in over a year, or you can see obvious dirt, bird droppings, or streaking from the ground, cleaning is often one of the first things worth addressing.
If production improves afterward, you’ve identified the cause without replacing any equipment.
Step 3: Review Your Monitoring App
Modern solar systems provide homeowners with valuable information through monitoring software.
Before scheduling a service visit, open your monitoring app and look for:
Production trends
System alerts
Error codes
Offline notifications
Communication failures
Individual panel performance (if available)
Many monitoring platforms can immediately indicate whether the issue involves:
The inverter
Microinverters
Optimizers
Communication hardware
Grid connection
Production levels
Some systems even identify exactly which panel or device has stopped reporting.
Taking a screenshot of any alerts before contacting a technician can help speed up the troubleshooting process.
Step 4: Check Your Inverter
If your monitoring app doesn’t provide enough information, your inverter can often tell part of the story.
Depending on the manufacturer, your inverter may display:
Error codes
Warning lights
Status messages
Fault indicators
Production information
Common examples include:
Grid faults
Ground faults
Arc faults
Communication errors
Overvoltage warnings
Isolation faults
While homeowners generally shouldn’t attempt repairs themselves, documenting the exact error code helps technicians diagnose the issue more efficiently.
Step 5: Look for a Tripped Breaker
Sometimes the problem isn’t the solar equipment at all.
A tripped breaker may prevent the inverter from operating correctly.
If you’re comfortable doing so, check your electrical panel for any breakers that appear to have tripped.
If you find one, don’t repeatedly reset it if it trips again.
A breaker that won’t stay on usually indicates an underlying electrical problem that should be diagnosed by a qualified solar technician.
Repeatedly resetting breakers without identifying the cause can potentially create additional issues.
Common Causes of Solar Underperformance
If there are no obvious visual issues, several electrical problems could be affecting your system.
Some of the most common include:
Failing Microinverter
Microinverters convert power from individual solar panels.
If one fails, the affected panel may stop producing while the rest of the system continues operating normally.
Because only one panel is affected, homeowners often notice a gradual decline rather than a complete system shutdown.
Failed Optimizer
SolarEdge systems use power optimizers beneath each panel.
A failed optimizer can significantly reduce production from one module while the rest of the array continues operating.
Monitoring software often identifies these failures.
Inverter Problems
String inverters are responsible for converting DC electricity into usable AC power.
If the inverter develops a fault, production from an entire section—or even the entire system—may be affected.
Fortunately, inverter monitoring usually provides detailed fault information.
Loose Electrical Connections
Solar systems experience years of heating and cooling cycles.
Over time, electrical connections may loosen.
Loose wiring can create:
Voltage drops
Reduced production
Intermittent operation
Arc faults
Complete circuit failures
These issues require professional inspection.
Damaged Wiring
Animals occasionally chew wiring beneath solar panels.
Weather, age, or accidental damage can also affect electrical conductors.
Damaged wiring often requires testing with specialized equipment to locate the exact fault.
Communication Issues
Sometimes the solar system is producing electricity normally, but the monitoring app stops displaying accurate information.
Communication failures between the inverter, internet gateway, or monitoring platform can make it appear that production has dropped even when the system is operating correctly.
A diagnostic inspection can determine whether the issue is with production or simply reporting.
Don’t Forget About Shading
Shade is one of the most common reasons homeowners experience lower production over time.
Trees continue growing year after year.
A branch that barely touched the edge of your array five years ago may now shade several panels every afternoon.
New buildings, fences, chimneys, satellite dishes, or even neighboring home additions can also introduce shading that didn’t exist when your system was originally installed.
Comparing current shade conditions with older photographs of your roof can sometimes reveal the source immediately.
Animal Activity Can Affect Performance
Birds, squirrels, and other small animals occasionally create problems beneath solar arrays.
Common issues include:
Bird nests
Chewed wiring
Debris accumulation
Restricted airflow
Damaged insulation
Bird droppings can also reduce production by creating localized shading across multiple solar cells.
If you notice increased bird activity around your roof, it’s worth having the system inspected.
Installing critter guard after repairs are completed can help prevent future animal-related issues.
Weather Can Influence Production
Not every production decrease indicates a malfunction.
Cloud cover, smoke from wildfires, haze, snow accumulation, and seasonal daylight changes all naturally affect energy production.
Comparing today’s output with another cloudy day isn’t particularly helpful.
Instead, compare similar weather conditions across previous months or years.
Looking for long-term trends provides a much clearer picture of whether your system is actually underperforming.
When Cleaning Doesn’t Solve the Problem
If you’ve already cleaned the panels and production remains lower than expected, you’ve successfully eliminated one of the most common causes of reduced performance.
At that point, the issue is more likely to involve:
Electrical equipment
Wiring
Inverter operation
Optimizers
Microinverters
Communication hardware
Grid connection
Protective devices
Rather than continuing to guess, a professional solar diagnostic inspection becomes the next logical step.
What Happens During a Solar Diagnostic Visit?
A professional solar diagnostic inspection is designed to identify the actual cause of reduced production—not simply replace parts based on assumptions.
Depending on the system, the inspection may include:
Reviewing production history.
Comparing expected versus actual output.
Reading inverter fault codes.
Inspecting the solar panels.
Testing electrical connections.
Checking breakers and disconnects.
Evaluating microinverters or optimizers.
Inspecting wiring for damage.
Looking for shading or debris.
Identifying bird nests or critter damage.
By following a systematic troubleshooting process, technicians can isolate the exact source of the problem instead of relying on trial and error.
Why Guessing Can Become Expensive
One of the biggest mistakes homeowners make is assuming the most expensive component must be the problem.
Replacing an inverter won’t solve production issues caused by dirty panels.
Replacing optimizers won’t fix a tripped breaker.
Replacing panels won’t correct a communication failure.
Without proper diagnostics, it’s easy to spend money replacing perfectly functional equipment while the actual issue remains unresolved.
A thorough inspection saves both time and unnecessary repair costs.
When Should You Call a Professional?
It’s a good idea to schedule a professional solar diagnostic inspection if:
Your monitoring app shows a steady decline in production.
Your inverter displays fault codes.
Your utility bills have increased unexpectedly.
Cleaning the panels didn’t restore production.
Individual panels have stopped reporting.
Breakers continue tripping.
You notice animal activity beneath the array.
The system shuts down unexpectedly.
You suspect wiring damage.
You’re unsure whether the problem is electrical or environmental.
The sooner the issue is identified, the sooner your system can return to producing the clean energy it was designed to generate.
Start With the Simple Things—Then Diagnose the Rest
When a solar system begins underperforming, it’s easy to assume the worst. Fortunately, many production issues have straightforward explanations. Dirt, debris, new shade, bird activity, or a tripped breaker can all reduce energy production without requiring major repairs.
If those simple checks don’t explain the problem, the next step is a professional diagnostic inspection. By reviewing your production history, inspecting the equipment, testing electrical components, and evaluating the entire system, a technician can pinpoint the real cause instead of relying on guesswork.
Whether the solution is as simple as a professional solar panel cleaning or as involved as replacing a failed microinverter, optimizer, or inverter, identifying the actual problem first is the fastest, most cost-effective way to get your solar system back to producing at its full potential.
Not sure why production dropped? See our solar diagnostics service in Box Elder County.