Solar panel maintenance checklist: Your annual guide

Why a solar panel maintenance checklist matters

NREL’s research puts typical panel degradation at about 0.5% a year, according to the National Renewable Energy Laboratory. Neglected systems can lose output noticeably faster. That difference compounds over 25 years—it’s the gap between a system producing 88% of rated output in year 25 versus one limping along at 60%.

A structured maintenance routine catches issues early. Routine checks keep production up and catch small problems before they turn into expensive repairs. Most problems don’t announce themselves with flashing lights—they show up quietly as a 5% dip in your monitoring app, or not at all until a professional inspection finds them.

Maintenance also protects your warranty. Keep a simple log of service visits, inverter alarms, downtime and anything you notice that hurts performance. The log makes it easier to spot recurring problems and gives you documentation if you ever need to file a warranty claim. Most panel and inverter warranties require proof that you’ve maintained the system according to manufacturer guidelines. If you need help understanding what your warranty covers, read our guide on how long solar panels last.

Monthly tasks: Monitor performance

The most useful habit is a monthly look at your production numbers. Every major inverter brand, including Enphase, SolarEdge, Fronius and GoodWe, has an app or web portal that shows daily, monthly and yearly production in kWh. This five-minute check catches production drops before they cost you hundreds in lost output.

What to look for:

• Compare month-to-month: Check this month’s production against the same month last year. Seasonal variation is normal—June will always outproduce December—but a sudden 10% drop compared to last June is not.
• Check for error codes: Most apps display inverter alerts. Call a professional if an error code won’t clear after a restart, and treat any ground fault alert as urgent, because it can mean damaged wiring.
• Verify all panels are active: In panel-level monitoring systems (Enphase microinverters, SolarEdge optimizers), make sure every panel shows up green in the app. A grey or inactive icon means that panel isn’t producing.

Keep a simple log—a spreadsheet or note on your phone—with monthly production totals. This creates a baseline that makes it easy to spot when something changes. It also serves as documentation if you ever need to file a warranty claim.

Seasonal tasks: Visual inspection and cleaning

Twice a year—ideally spring and fall—walk around your property and look at your system. You’re not climbing on the roof or opening electrical boxes. You’re checking what you can see safely from the ground.

Spring inspection (late March to May)

This is the best time for your annual cleaning. If you only clean once a year, schedule it for late spring, after pollen season ends and before the long summer production days.

What to check:

• Panel surface: Look for visible debris, bird droppings, pollen buildup, or leaves. Most homes need a cleaning once or twice a year, and more often in dusty or polluted areas.
• Shading changes: Has a tree grown taller? New construction nearby? Even partial shade on one panel can reduce output for the entire string on older systems.
• Mounting hardware: Check that racking and clamps look secure. You’re not tightening anything—just noting if something looks visibly loose or corroded.
• Inverter area: Make sure vents aren’t blocked by debris, weeds, or storage items. Inverters need airflow to stay cool.

Fall inspection (September to November)

This is your pre-winter check. Look for the same items as spring, plus:

• Roof penetrations: Check flashing around roof mounts for any visible gaps or lifted edges. Water intrusion is rare but easier to fix before winter.
• Wiring condition: If you can see the roof edge safely, check that the black cables and MC4 connectors between panels aren’t sagging, rubbing on shingles or pinched by the racking.
• Animal activity: Look for nesting materials under panel edges or droppings that suggest rodents or birds are getting under the array.

If you’re not comfortable doing visual inspections yourself or your roof is too steep to view safely from the ground, many installers sell annual maintenance plans, usually around $100 to $200 a year, that bundle an inspection, a cleaning and an inverter check. Find qualified professionals through our solar installer directory.

If you find nesting material or droppings under the array, see what critter guards cost and when they’re worth it.

Annual deep inspection: What to check once a year

Once a year, ideally in late winter or early spring before peak season, give the whole system a closer look. This is when you look at everything: production data, physical condition, electrical connections, and inverter health.

A professional annual inspection on a home system usually takes 60 to 90 minutes and follows a standard checklist. You can do much of this yourself if you’re comfortable, or hire a professional for $200–$400 depending on your market.

Production analysis

Pull a full year of data from your monitoring platform. Compare actual generation to your original production estimate (usually in your installation contract or proposal). If a month comes in more than about 5% below the same month in prior years and you can’t explain it, investigate.

Account for weather variation—an unusually cloudy year will reduce output. If you’re not sure what’s normal, our article on how solar panels perform in winter and cloudy weather explains what to expect.

Inverter health check

Your inverter is the most failure-prone component in a solar system. Most string inverters last 10 to 15 years, so expect to replace one at least once over the life of your panels. Catching problems early extends that lifespan.

Check for:

• Error log: Most inverters log fault codes even if they reset automatically. Review the log in your monitoring platform or on the inverter display. Frequent errors—even if they clear—indicate a developing problem.
• Ventilation: Fan-cooled inverters need their air filters cleaned every year or two. A clogged filter causes overheating and shortens inverter life.
• Mounting security: Verify the inverter is still firmly mounted to the wall or racking. Vibration from the cooling fan can loosen bolts over time.
• Unusual sounds or smells: If you smell burning or see scorch marks near the inverter, call an electrician before you reset anything.

Physical panel condition

From the ground or with binoculars, look for:

• Cracks in the glass or frame
• Discoloration (yellowing or browning, which indicates delamination)
• Hot spots visible as darker patches (requires thermal imaging—professional service)
• Loose or corroded mounting clamps

Most of these issues are rare on systems less than 10 years old. Plan a full electrical inspection every 4 to 5 years and after any severe storm.

Cleaning: How often and how to do it safely

Solar panel cleaning frequency depends entirely on your environment. Panels tilted at least 5 to 10 degrees are usually rinsed well enough by rain. If you have a standard pitched roof in a suburban area with regular rainfall, nature does most of the work.

Clean when it hasn’t rained in a long time, after nearby construction, plowing or a dust storm, when you can see heavy or patchy grime, or if your panels are mounted flat.

When cleaning is needed:

• Desert or high-dust areas: Clean every 2–3 months. Soiling losses can reach 15–20% in these climates.
• Coastal areas: Salt spray buildup requires cleaning 2–3 times per year.
• Heavy tree cover: Pollen, sap, and leaves mean 2–4 cleanings annually.
• Average suburban: Once or twice a year is sufficient for most homes.

If you’re doing it yourself, follow NREL’s guidelines: Rinse panels while they’re cool, not in midday sun, to avoid thermal stress on the glass. Use a soft brush or just water—no abrasive cleaners, which can damage the anti-reflective coating. Never walk on the panels.

Professional cleaning typically costs $150–$450 for a residential system (see our solar panel cleaning cost guide for DIY vs. pro). NREL estimates typical soiling losses at about 5%, and a cleaning in that price range wins most of it back. For most homeowners, the cost pays for itself in recovered production within the same year.

Not sure if cleaning is worth it? Check your monitoring app. If production has dropped more than 10% compared to the same month last year and there’s visible dirt on the panels, cleaning will likely bring output back up.

What professionals check during a full inspection

If you hire a professional for an annual inspection, here’s what they should cover. This list is useful whether you’re vetting a service provider or deciding if you need professional help at all.

Panels: cracks, delamination, discoloration, hot spots and micro-cracks that only show at certain angles. Mounting: rail condition, clamp torque, flashing and any corrosion or movement. Wiring: sun damage on exposed cable, secure terminations and sealed junction boxes. Inverter: error codes, fault history, ventilation and heat damage. Production: output compared with what’s expected for the season.

Advanced diagnostics—typically done every 5 years or when problems are suspected—include:

• Thermal imaging: Identifies failing cells, hot spots, and electrical faults not visible to the eye.
• Insulation resistance testing: Verifies wiring integrity and detects degradation before it causes a failure.
• String voltage and current testing: Confirms each panel string is producing within spec.

Most homeowners don’t need advanced testing unless the system is over 10 years old or production has dropped unexpectedly. If the system is performing as expected, a full professional inspection every five to ten years is generally enough.

When choosing a service provider, verify they’re licensed electricians or certified by your inverter manufacturer. If your original installer is no longer in business, our guide on what to do when your installer goes out of business explains how to find qualified replacement service.

Record keeping: Why documentation matters

Keep a simple maintenance log—digital or paper—that tracks:

• Monthly production totals
• Cleaning dates and who did the work
• Any error codes or alerts from the inverter
• Dates and findings of visual inspections
• Professional service visits with copies of reports
• Photos of any damage or unusual conditions

This log is your insurance policy. If you need to file a warranty claim for a failed panel or inverter, manufacturers often ask for proof of maintenance. A timestamped log showing you’ve monitored the system, cleaned it regularly, and addressed issues promptly strengthens your claim.

Documentation also helps when troubleshooting. If production drops, you can compare current conditions to your baseline. Is this the first time you’ve seen this error code, or has it been happening intermittently for months?

Finally, good records add value if you sell your home. Buyers want proof that the system has been maintained. A complete log, especially with professional service reports, shows the system is in good condition and reassures buyers they’re not inheriting deferred maintenance. For more on this, see our guide on buying a home with solar panels.

When to call a professional

Most maintenance is observation and basic cleaning. But some situations require an electrician or solar technician immediately:

• Electrical issues: Any burning smell, scorch marks, or sparking near the inverter or electrical connections. Shut off the system at the AC and DC disconnects and call a professional before turning it back on.
• Persistent error codes: A ground fault alert can point to a wiring problem that needs attention right away. If an error code doesn’t clear after a reset or keeps coming back, don’t ignore it.
• Major production drop: If output has fallen 15% or more compared to the same period last year and cleaning doesn’t recover it, you likely have a hardware failure—a bad panel, failed optimizer, or inverter issue.
• Physical damage: Cracked panels, broken glass, damaged conduit, or compromised roof flashing all need professional repair.
• After severe weather: Hail, high winds, or fallen tree branches warrant a professional inspection even if the system appears to be working. Damage isn’t always immediately visible.

For routine maintenance and inspections, start with your original installer if they’re still in business. They know your system and have records of the installation. If they’re gone or unresponsive, use our installer directory to find a local solar service provider. Look for companies that are certified by your inverter manufacturer—SolarEdge, Enphase, Fronius, and SMA all maintain lists of authorized service providers.

Expect to pay $200–$500 for a comprehensive annual inspection and $100–$300 for cleaning, depending on system size and roof accessibility. That investment protects an asset worth $15,000–$40,000 and ensures you’re getting the energy production you paid for.

After a major storm, also see how to file a storm damage insurance claim.