Every modern solar inverter in a Cebu home — whether it is a Solis hybrid, a Huawei string inverter, or a Fronius — the grid ships with a phone app that shows you production in real time. Most homeowners install the app, glance at it once or twice, and never look again. That is a missed opportunity, because the app is the single best diagnostic tool for your system. It tells you whether the system is producing what it should, whether a string is underperforming, and whether the panels need cleaning after a particularly dusty week.
This guide walks through what every number on the screen means, what good looks like for a Cebu home, and what to do when something is off.
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The four numbers that matter most
Most solar monitoring apps show a similar set of metrics. Four of them cover 95% of what you actually need to know:
- Current power (W or kW) — what your system is producing right now.
- Energy today (kWh) — total production so far today.
- Energy this month (kWh) — cumulative production for the current billing cycle.
- Energy total (kWh or MWh) — lifetime production since install day.
Power is the live number. Energy is the cumulative one. Together, they let you check whether the system is healthy at any moment and whether it has performed over time.
For a 5 kW system in Cebu with 5-6 peak sun hours per day, a healthy production curve looks like this:
- At 7 AM (early morning sun): around 500 W to 1.2 kW. The panels are producing but the sun is still low.
- At 11 AM (approaching noon): 4.0 to 4.8 kW. Close to the system’s nameplate capacity.
- At 1 PM (peak): 4.5 to 5.0 kW. This is the daily high. In Cebu, expect to see this from late March through May, the clearest, driest stretch of the year.
- At 4 PM (afternoon sun): 3.0 to 4.0 kW.
- At 6 PM (sunset): 200 W to 800 W. By 6:30 PM the inverter has typically shut down for the day.
How to compare against your actual generation estimate
The installer should have given you a generation estimate when they proposed the system — usually a single kWh-per-year number and a monthly breakdown. For a 5 kW system in Cebu, this typically lands between 7,500 and 8,500 kWh per year, depending on roof orientation and shading.
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To check whether your system is hitting the estimate, divide the install-day kWh total on your app by the number of days since installation. That gives you lifetime daily average. Compare it to your expected daily average from the proposal (annual kWh divided by 365).
Two practical shortcuts:
- After 30 days: compare lifetime daily average to estimate. Within 10-15% is normal (weather variability is high month-to-month).
- After 12 months: compare lifetime daily average to estimate. Within 5% is expected. More than 10% below estimate means something is wrong.
What a healthy daily curve looks like
Open the app’s "today" or "graph" view. You should see a bell-shaped curve — low at sunrise, ramping up through the morning, plateauing near the system’s rated capacity from late morning to early afternoon, then ramping down through the afternoon to zero by sunset.
The shape of the curve is diagnostic. Three things to look for:
Flat-top plateau. On a clear day, the curve should flatten near your system’s rated power from roughly 10 AM to 2 PM. If the top of the curve is much lower than your rated capacity — say, your 5 kW system tops out at 3.8 kW on a clear noon — something is wrong. Common causes: a string is disconnected, a panel is shaded, or the inverter is in a power-limiting mode due to grid instability.
Symmetric shape. A healthy system ramps up and down at roughly similar rates. If the morning side climbs much faster than the afternoon side falls (or vice versa), you may have shading on one side of the array — usually the west side, since afternoon sun comes from the west and is more likely to be blocked by a roof feature or a neighbor’s structure.
Smooth line, not jagged. A few small dips are normal (passing clouds cause brief drops). A jagged, sawtooth pattern that does not match the weather outside usually indicates a loose DC connection or an MPPT that is hunting because of a mismatched string.
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What to do when production looks low
If your app says the system is underperforming, work through this checklist before calling your installer:
- Is the inverter online and showing no error code? Most apps show a status indicator (green dot, "running", etc.). If it shows red or an error code, screenshot it and send to your installer. Many error codes clear themselves after a power cycle, but some need a service visit.
- Are all strings showing production? If your system has two MPPT inputs (most do), the app usually shows production per MPPT. If one MPPT is producing 80% of the other on a clear day, that string has a problem — usually shading, a dirty panel, or a failed panel.
- When did you last clean the panels? Cebu’s combination of coastal salt, construction dust in growing areas (Mandaue, Talisay), and agricultural dust in outlying barangays means panels often need cleaning every 2-4 months. A dirty panel can lose 10-25% of its output.
- Has there been any construction or new shading? A new building, a new tree, or a new antenna on a neighbor’s roof can shadow your array starting at a specific time of day. The app’s hourly graph usually shows when the dip starts — and that time corresponds to when the new shading begins.
- Check the weather. Compare your day’s production to actual conditions, not your expectation. A heavy habagat day with sustained overcast might give 30% of a clear day’s output — that is the system working correctly, not a fault.
Monthly and annual checks
Beyond the daily glance, do three checks at predictable intervals:
Monthly: Compare "energy this month" to the same month last year. If you have 12 months of data, this is the most reliable health check you can do. Production should be within 5-8% of the same month in prior years. Bigger drops usually mean cleaning is overdue or a component has degraded.
Annually: Compare "energy total" divided by days installed to your annual estimate divided by 365. If you are consistently 10%+ below the estimate after a full year, schedule a service visit. Common culprits: aging inverter (efficiency drops 0.5-1% per year), degrading panels (about 0.5% per year is normal, but accelerated degradation above 1% per year is a warranty issue), or persistent shading that has gotten worse.
After major weather: Typhoons, habagat storms, and unusual lightning activity should trigger a one-off check. Most systems ride out storms fine, but if production drops after a major weather event, a visual roof inspection and inverter diagnostic are worth doing.
The numbers that should never move
Two metrics in the app are essentially constant and should never change unless something is wrong:
- System rated power. This is the nameplate capacity (5 kW, 8 kW, etc.). If your app suddenly lists a lower number, the inverter has reset or a string is offline.
- Cumulative energy total. This only goes up, never down, and never resets (except on a hardware swap). If it drops or resets to zero, the inverter has lost its memory — usually a sign of a failing memory chip or a recent firmware issue.
When to call your installer
Three scenarios are worth a phone call:
- Persistent error code that does not clear after a power cycle (turn the inverter off at the DC isolator, wait 60 seconds, turn back on).
- One MPPT or string consistently at 60-70% of the other on clear days with no obvious shading — usually a failed panel or a loose MC4 connector.
- Annual production 15%+ below the original estimate after a full year of operation — this is the threshold where a service visit pays for itself.
The bottom line
Your solar monitoring app is not just a vanity dashboard. It is the only diagnostic tool that knows what your system has been doing for the past 6 months. A 30-second check once a week, plus a monthly comparison, will catch 90% of problems before they become expensive. Combine that with the production estimate from your installer and a rough cleaning schedule, and your system should hit its 25-year design life without surprises.
If you want to know what your roof can actually produce before you install, our free site survey includes a shade analysis and a custom production estimate based on your actual roof orientation, not a generic calculator.