What You Need to Know About Solar Panel Inspection

Residential solar panels are often treated as a “set-it-and-forget-it” upgrade. Many assume that once they’re installed and producing power, solar panels will quietly do their job for decades with little maintenance. Like other home systems, solar panel systems are mechanical, electrical and have structural assemblies that are exposed to weather, temperature swings and the effects of time. They need regular inspection.

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A proper solar panel inspection checklist helps catch small issues before they turn into performance losses, safety hazards or expensive repairs. Whether you’re doing a DIY system check or preparing for a professional inspection, knowing what to look for — and why it matters — is essential.

How Often Do Solar Panels Need to Be Checked?

Residential solar panels should be inspected at least once per year. Annual inspections strike the right balance between preventive maintenance and practicality. There are situations where more frequent inspections make sense, including:

• After severe weather, like hail, high winds, heavy snow and hurricanes

• If energy production drops unexpectedly

• After roof work or nearby construction

• If the system is more than 10 years old, when degradation-related issues become more common

It's also commonplace to combine a visual inspection with a performance review of their monitoring app. If production numbers don’t match expectations (especially when net metering credits decline), that’s often the first sign something needs attention.

What to Look For When Inspecting Your Solar Panels

Check out our practical, homeowner-focused solar panel inspection checklist that covers both what to look for and why it matters.

Photovoltaic Module Surface Damage

The photovoltaic (PV) cells beneath the glass are responsible for converting sunlight into electricity. Surface damage reduces light transmission and can expose internal components to moisture. Even small cracks can accelerate long-term degradation and reduce system output.

Look for:

• Cracked or chipped glass

• Discoloration or cloudy areas

• Impact marks from debris or hail

Microcracks in Solar Cells

Microcracks typically form during shipping, installation or thermal expansion and contraction over time. While they may not cause immediate failure, they interrupt electrical pathways inside the panel, gradually reducing efficiency and increasing the risk of hotspots.

Look for:

• Hairline fractures not always visible to the naked eye

• Irregular cell patterns visible under certain lighting

Hotspots (Overheating Areas)

Hotspots occur when part of a panel underperforms due to damage, shading or internal resistance. Excess heat accelerates degradation, reduces power output and can become a fire risk. Professional inspections often use infrared (IR) thermography to detect hotspots invisible to the eye.

Look for:

• Panels that feel unusually hot compared to others

• Burn marks, browning or melted connectors

• Issues identified through IR thermography

Inverter Performance and Error Codes

The inverter converts direct current (DC) electricity from the panels into usable AC power for your home. Inverter issues are one of the most common causes of reduced solar output. Catching inverter problems early can prevent prolonged downtime and lost net metering credits.

Look for:

• Warning lights or error messages

• Unusual noises or overheating

• Unexpected system shutdowns

Delamination of Solar Panels

Delamination allows moisture and air to penetrate the panel, accelerating corrosion and electrical failure. Once delamination starts, panel performance usually declines steadily and replacement may be necessary.

Look for:

• Bubbling or peeling layers

• Visible separation between panel components

• Moisture trapped inside the panel

Racking and Mounting Hardware

Racking secures the panels to your roof and keeps them aligned for optimal sun exposure. Loose or corroded hardware increases the risk of wind damage and roof leaks, especially during storms.

Look for:

• Loose bolts or clamps

• Corrosion on metal components

• Panels shifting or sitting unevenly

Roof Flashing and Penetration Seals

Improper flashing is one of the most common long-term issues with rooftop solar installations. Even small failures can lead to roof leaks, insulation damage and mold, problems that extend well beyond the solar system itself.

Look for:

• Cracked or lifting flashing

• Dried, brittle or missing sealant

• Signs of water intrusion in the attic

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Electrical Conduit and Wiring

Conduit protects electrical wiring from UV exposure, moisture and pests. Damaged conduit can lead to electrical faults, ground faults or complete system shutdowns. Rodent damage is also a surprisingly common issue with residential solar installations.

Look for:

• Cracked or loose conduit

• Exposed or chewed wiring

• Sagging or improperly secured runs

Net Metering and Production Data

Monitoring data often reveals problems before physical damage is obvious. Declining production may signal panel degradation, inverter issues or shading changes caused by tree growth or nearby construction.

Look for:

• Sudden drops in energy production

• Net metering credits lower than expected

• Mismatches between historical and current output

Long-Term Degradation Trends

All solar panels degrade over time, typically around 0.5% per year. Accelerated degradation can indicate underlying defects, microcracks or environmental damage. Tracking performance helps distinguish normal aging from correctable problems.

Look for:

• Gradual year-over-year output decline beyond normal rates

• Panels underperforming compared to manufacturer specs

When to Call a Professional For Solar Panel Inspection Services

While you can safely perform visual inspections and review monitoring data, certain evaluations (IR thermography, electrical testing and roof penetration assessments) are best left to professionals. If your inspection reveals damage, persistent performance loss or safety concerns, a licensed solar technician or qualified roof professional can help diagnose and resolve the issue before it escalates. Solar panel technicians or inspectors can provide you with an inspection report that will help you better understand how to proceed.

A routine solar panel inspection helps to protect not only your solar panels, but also your roof and electrical system. It can help to provide a long-term return on your solar investment.