Why Is My Solar Not Producing?
Short answer: start with your monitoring app. If the whole system reads zero on a sunny day, the usual causes are a faulted or powered-down inverter, a tripped breaker or disconnect, or a Wi-Fi dropout — in which case your panels are fine and only the reporting stopped. Low but not zero is usually shading, soiling, or normal seasonal variation. Here’s how to tell a real fault from normal.
Get a free estimate
- Check the monitoring app first — per-panel if you have microinverters or optimizers, whole-system if you have a string inverter.
- A whole-system zero on a sunny day usually means the inverter, a tripped breaker/disconnect, or a Wi-Fi dropout — not necessarily a dead system.
- Low but not zero is usually shading, soiling, or normal seasonal/weather variation. Compare to the same month last year, not to summer.
- Read the app, reboot the router, reset a tripped solar breaker once, rinse from the ground — but leave the inverter, DC wiring, and the roof to a licensed pro.
First stop: what the monitoring app is telling you
Almost every diagnosis starts in your solar app. How much it shows depends on your hardware: microinverters or DC optimizers report each panel separately, so the app can pinpoint one bad module while the rest keep producing. A plain string inverter reports one whole-system number, so a single weak or shaded panel is harder to spot. Either way, compare today against a similar sunny day — or the same month a year ago — not against your summer peak.
Solar troubleshooting at a glance
Match your symptom to the likely cause, a safe check you can do yourself, and the point where it’s time to call a licensed pro. Details on each follow below.
| Symptom | Likely cause | Safe DIY check | When to call a pro |
|---|---|---|---|
| Whole system shows 0 W on a clear day | Inverter faulted or powered down; a tripped solar breaker or AC/DC disconnect; or a comms dropout | Look at the inverter for a red/amber light or blank screen; confirm the solar breaker and the AC & DC disconnects are ON | Red fault light or error code, a breaker that trips again, any burning smell or heat |
| App shows “no data” / gateway offline, but it’s sunny | Wi-Fi or monitoring dropout — production is almost certainly fine, only the reporting stopped | Reboot your router and the gateway/logger; give it 15–30 minutes to reconnect | Data still missing after it reconnects, or repeated dropouts |
| One panel or one string reads low/zero, the rest look normal | A failed microinverter or optimizer, or localized shade/debris on that module | Open the panel-level view (if you have microinverters/optimizers) and check that spot for a new shadow or debris | A clean, unshaded panel that stays at zero — likely a module-level hardware fault |
| Output down ~10–25% and slowly drifting lower | Soiling: dust, pollen, or bird droppings after a dry stretch | Look for a visible film; a good rain usually restores most of it | A gentle rinse doesn’t recover it — have the output checked |
| A new, permanent dip at one time of day | New shading — a grown tree, new construction nearby, or a newly added vent/antenna | Note the hour the dip starts and see what casts a shadow then | Ask about trimming or panel-level electronics to limit the loss |
| Lower output that follows the season or a cloudy week | Normal seasonal or weather variation — not a fault | Compare to the same month last year, not to summer | Only if it’s far below a normal seasonal year and won’t recover |
| Whole system dark right after an outage or PSPS | Grid-tied anti-islanding shutdown with no battery — required for safety | Normal; it should restart on its own once grid power is steady again | It stays down well after power is clearly back |
| A slow decline of about half a percent a year over many years | Normal panel degradation | Compare multi-year annual totals, not day to day | A sudden step-down isn’t degradation — investigate that separately |
Sources: NREL soiling study · Enphase support · SolarReviews. DIY checks are limited to what’s safe from the ground — never open equipment or climb the roof.
Grid-tied solar goes dark in an outage — on purpose
If utility power is out (including a PSPS), a grid-tied system without a battery shuts down within about two seconds and stays off until the grid is back. That’s anti-islanding: the inverter won’t push electricity onto lines that utility crews may be working on (UL 1741 / IEEE 1547; rapid-shutdown rules under the applicable NEC edition are a related safety layer, and the exact behavior depends on your equipment and the code your system was permitted under). It’s a safety feature, not a fault — only a battery with the right backup wiring keeps your lights on. More in solar, batteries & outages in California.
Whole system at zero: inverter, breaker, or Wi-Fi
Three causes cover most system-wide zeros. First, the inverter: check it for a red or amber light or a blank screen, and note any error code in the app. A string inverter is a single point of failure — if it faults, the whole array stops; microinverters isolate the problem to one panel instead. Second, a tripped breaker or disconnect: a solar breaker that has tripped, or an AC/DC disconnect left in the OFF position, will zero the system. If you’re comfortable doing so, you can switch a tripped solar breaker back on once — but if it trips again, stop and call a pro. A repeat trip is a fault signal, not a nuisance, and forcing it is unsafe.
Third, and most common, a Wi-Fi or monitoring dropout. If the app reads “no data” or “gateway offline” while the sun is out, your panels may still be producing — verify the inverter status or your utility meter before assuming it’s only a reporting issue; the gateway only reports data; it isn’t part of generating power (the manufacturers say so plainly). Reboot your router and the gateway and give it time to reconnect; the missing hours usually backfill on their own. Which disconnects and shutdown steps apply to your system depends on your equipment and the code edition it was permitted under.
When “zero production” was just the Wi-Fi
On one Northridge system, the owner’s app showed a flat zero for two days and they feared the inverter had died. The culprit was a swapped-out home router — the gateway simply couldn’t reach the internet. The panels had been producing the entire time, and reconnecting the gateway backfilled the missing data. Across 2,000+ projects since 2017, a communication dropout is among the most common “my solar stopped” false alarms we see. See more of our Northridge installs.
One panel or one string is down
Here’s where your inverter type really matters. With microinverters or optimizers, each module reports on its own, so the app pinpoints the exact panel and the others keep producing — one non-communicating microinverter usually means just that panel is offline. With a plain string inverter, panels share a circuit, so a single shaded or weak module can drag the whole string down and it’s harder to see which one. If a clean, unshaded panel sits at zero on a clear day, that points to a module-level hardware fault — a warranty matter, though coverage, registration, and transfer terms vary by manufacturer and contract. We compare the two designs in Enphase vs SolarEdge.
Low but not zero: the normal culprits
If your system is producing, just less than you expected, the cause is usually one of these — and most are normal.
New shading
A tree that grew in, new construction next door, or a newly installed vent or antenna can throw a shadow that wasn’t there at install. Note the time of day the dip starts.
Soiling
Dust, pollen, and droppings build up through California’s dry months and can shave ~5% off a year — more during a long rain-free stretch (NREL). A good rain usually resets it.
Season
Shorter days and a lower winter sun angle commonly pull output well below the summer peak. That’s expected — compare to the same month last year, not to July.
Weather
A cloudy or marine-layer week reads low and recovers on its own. One gray day proves nothing; look at the weekly and monthly trend instead.
Heat
Very hot days slightly reduce panel efficiency even in full sun — usually a minor effect. More in heat & solar output in LA.
Age
Panels lose roughly half a percent a year — real but slow, and not a sudden drop. See degradation in California.
Real fault vs. normal variation — how to tell
Usually normal: a dip that is gradual, seasonal, or weather-linked; output that recovers after rain or when the sun returns; or numbers that match the same month a year ago. Worth a call: a hard zero on a sunny day, a red fault light or error code, a breaker that keeps tripping, a single clean panel dead on a clear day, or output far below a normal seasonal year that won’t recover. When in doubt, screenshot the app — the whole-system graph plus any error code — before you call. It speeds up the diagnosis and often saves a trip.
Leave the equipment — and the roof — to a pro
You can safely read the app, reboot a router, switch a tripped solar breaker back on once, and rinse panels from the ground with a hose. Don’t open the inverter, touch DC wiring or connectors, or climb onto the roof: solar DC stays live whenever the sun is up, and roof work is a real fall hazard. Call a licensed installer for any red fault light or ground/isolation-fault code, a breaker that trips again, a burning smell, or a panel that stays dead. A qualified pro can pull your monitoring history and test the system safely — and if it turns out to be a covered manufacturing defect, it may fall under your written warranty.
Get your system checkedProducing fine, but the bill went up?
One last check: confirm you actually have a production problem. If your monitoring shows normal output but your bill still climbed, that’s a billing question — true-up timing, fixed charges you can’t erase, a rate-plan change, or how your utility and tariff credit exports — not a broken system. We sort those out in why your bill went up after solar. And for the routine cleaning and checks that prevent output loss in the first place, see solar panel maintenance in California.
Frequently asked
Why is my solar system showing zero production?
On a sunny day, a whole-system zero usually means one of three things: the inverter has faulted or lost power (look for a red/amber light or error code), a solar breaker or AC/DC disconnect is tripped or off, or a Wi-Fi/monitoring dropout has stopped the reporting while the panels keep producing. Check the inverter light and the solar breaker first; if the app says “gateway offline,” it’s usually just the reporting.
My solar app shows no data — is my system broken?
Usually not. A gateway or monitoring dropout is a communication issue, not a production one — the gateway only sends data to the app; it isn’t part of generating power, so your panels keep working. Reboot your router and the gateway and give it 15–30 minutes; the missing hours usually backfill. If data still doesn’t return or it keeps dropping, contact your installer.
Do solar panels work during a power outage?
Not by themselves. A grid-tied system without a battery shuts down within about two seconds of an outage — a safety feature called anti-islanding that keeps it from feeding lines utility crews may be working on — and restarts on its own once the grid is steady. Only a battery with the right backup wiring keeps your power on. See solar, batteries & outages.
Why is my solar producing less than usual?
If it’s low but not zero, the usual causes are new shading (a grown tree or new construction), soiling after a dry spell, or normal seasonal and weather variation. Compare to the same month last year, not to your summer peak. A hard zero, a red fault light, or a single clean panel reading zero is different — that’s worth a call.
Should I clean my solar panels to fix low output?
Sometimes. Soiling can cost about 5% a year in California, more during a long rain-free stretch, so dust, pollen, or droppings can explain a gradual dip. A rinse from the ground — or a good rain — often restores most of it. Never climb the roof. If a clean doesn’t help, have the output checked. More in solar panel maintenance.
When should I call a professional about solar output?
Call a licensed installer for a red fault light or ground/isolation-fault code, a breaker that keeps tripping, a burning smell, a single clean panel dead on a clear day, or output far below a normal seasonal year that won’t recover. Don’t open the inverter, touch DC wiring, or go on the roof — a pro can pull your monitoring history and test the system safely.
Related reading
Solar output looking off? Get it checked
If your system has been dark or underproducing and you can't pin down why, our licensed team can pull your monitoring history and inspect it safely — no rooftop guesswork on your part.
Get a free estimatePrepared by Cali Energy, August 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)