If your solar system is producing less power than it used to, the cause is almost always one of seven things: dirty panels, new shading, a tripped breaker, an inverter fault, a monitoring dropout, physical panel damage, or a normal seasonal dip. In San Diego County, dust buildup during dry spells and inverter faults are the two most common culprits we diagnose. You can safely check five of the seven yourself in under 20 minutes — the other two need a licensed technician.
How much production loss is normal in San Diego?
A 10–20% swing between summer and winter output is normal for San Diego County rooftops; a sudden 30%+ drop is not. May-gray and June-gloom marine layer months routinely cut coastal production (Encinitas, Carlsbad, Ocean Beach) more than inland areas like Poway or Ramona. Solar panels also degrade naturally at roughly 0.5% per year — so a 10-year-old array producing 95% of its original rating is healthy. The rule of thumb worth remembering: seasonal drops are gradual and predictable, while equipment faults are sudden and persistent.
What can I check myself before calling anyone?
Five of the seven causes are homeowner-checkable. Work through them in this order:
- 1. Dust and grime. San Diego’s long dry season lets dust, pollen, and coastal salt film accumulate for months without rain to rinse it. A visibly hazy panel can lose 5–15% of its output. If panels are ground-reachable with a hose, rinse them at dawn with plain water — never spray cold water on hot midday glass.
- 2. New shading. Trees grow. A neighbor’s new addition, a new vent pipe, or a eucalyptus that gained three feet can shade one string and drag down the whole array on older central-inverter systems.
- 3. A tripped breaker. Check the dedicated solar breaker in your main electrical panel and the AC disconnect next to your meter. A breaker that trips repeatedly is a symptom, not a fix — leave it off and call a licensed electrician.
- 4. Inverter status lights. Your inverter (usually garage or exterior wall) shows a green light in normal operation. Red or flashing lights plus an error code mean a fault — note the code before you call; it cuts diagnostic time significantly.
- 5. Monitoring app dropouts. If your app shows zero production but your utility meter is still spinning backward mid-day, the monitoring gateway lost Wi-Fi — a reporting problem, not a production problem.
Which problems need a licensed solar technician?
Two failure modes should never be DIY: physical panel damage (cracked glass, burned spots, delamination, chewed wiring — common where squirrels nest under arrays) and any electrical fault behind the inverter’s error code. Solar arrays operate at several hundred volts DC even when the breaker is off, and rooftop electrical work in California must be performed by a licensed contractor. Hans Energy Systems is a CA-licensed contractor (LIC #967367) with a NATE-certified team that has serviced San Diego County systems since 2003 — including arrays we didn’t install. Our solar panel repair service starts with a full-system diagnostic: string voltages, inverter logs, connector inspection, and a production baseline against your system’s rating.
Why do inverters fail more often than panels?
Panels have no moving parts and routinely last 25+ years; inverters do the hard electronic work of converting DC to AC and typically last 10–15 years. The inverter is the component most likely to end a solar system’s life early — which is why a production drop on a 12-year-old system usually points there first. If your inverter is out of warranty, it’s worth reading our guide to what solar equipment actually costs in San Diego County before deciding between a like-for-like inverter swap and a broader system upgrade. Related reading: how a home battery backup works during an outage — many inverter replacements are a natural moment to add storage.
Frequently asked questions
How often should solar panels be cleaned in San Diego?
Once or twice a year for most of the county — typically at the end of the dry season (September–October) and after Santa Ana dust events. Coastal homes with salt film may benefit from an extra rinse. Rain in a wet winter does most of the work for free.
Do solar panels lose power as they age?
Yes, about 0.5% per year for quality panels. Most manufacturer warranties guarantee at least 80–85% of rated output at year 25. Faster degradation than that is a warranty conversation.
Why is my solar production zero but the sun is out?
Total zero production almost always means a tripped breaker, a faulted inverter, or a monitoring dropout — not the panels themselves. Check the breaker and inverter lights first.
Can I claim a warranty on underperforming panels?
Often, yes. Panels carry separate product and performance warranties (frequently 25 years), and inverters typically 10–12 years. A diagnostic report documenting the underperformance is what the manufacturer will ask for.
Does Hans Energy Systems repair solar systems it didn’t install?
Yes. We diagnose and repair most residential systems in San Diego County regardless of the original installer, including orphaned systems whose installer has gone out of business.
Know the cause — now compare your options. If your system is past its inverter’s lifespan, start with our cost guide: How much does solar panel installation cost in San Diego County? Or skip straight to a diagnosis: request a solar system checkup or call (619) 654-0055.
