Your solar monitoring app provides real-time and historical data on what your system is producing — but knowing how to interpret the numbers transforms monitoring from a passive dashboard into an active tool for catching problems and maximizing your system’s value. The three most important numbers to check are today’s production, lifetime production to date, and system efficiency versus your installer’s estimate. This guide explains every key metric and what it tells you about your system’s health.
Which Monitoring App You Have — and What It Shows
Your monitoring platform depends on your inverter brand:
Enphase Enlighten (enlighten.enphaseenergy.com or the Enlighten app): Shows per-panel production in real time, energy production and consumption (if a CT sensor is installed), battery state of charge, and historical data by day/week/month/year. Best granularity available — you can identify which specific panel is underperforming.
SolarEdge mySolarEdge (monitoring.solaredge.com or the mySolarEdge app): Shows system-level and per-panel data (the latter requires SolarEdge power optimizers on each panel). Includes lifetime energy production, current power, daily production graph, and inverter status indicators.
SMA Sunny Portal (sunnyportal.com): System-level production data, daily/monthly/annual charts, yield per day, CO2 offset equivalent. Good historical tracking; no panel-level granularity with standard SMA string inverters.
Fronius Solar.web (solarweb.com): Similar to SMA Sunny Portal — system-level data, production history, energy flow diagram when paired with a smart meter.
Sungrow iSolarCloud: Production history, real-time power, inverter status, fault alerts. Sungrow is increasingly common in newer US installations.
Third-party monitoring (Emporia Vue, Sense Energy Monitor): Installed independently of the inverter, these monitor whole-home energy flow — solar production, grid import/export, and individual circuit loads. More comprehensive energy management tool than inverter-specific monitoring.
Key Metrics and What They Mean
Current Power (kW or W): How much power your system is generating right now. On a clear day at solar noon (11 AM–1 PM), a well-functioning system approaches its rated capacity. An 8 kW system should show 7.0–8.0 kW at peak on a clear summer day. Overcast days: expect 0.5–2.5 kW. Morning and evening: lower due to sun angle. Zero power at night is normal.
What to watch for: if current power is significantly below expected on a clear midday with low shading, that’s a flag for investigation. A system showing 3 kW when it should show 7 kW at noon on a sunny day has a performance problem.
Energy Today (kWh): Total electricity generated so far today. On a clear summer day in a good solar location, a properly functioning 8 kW system should accumulate 35–50 kWh by the end of the day. Cloudy days: 5–15 kWh. Partial cloud: 15–30 kWh.
Compare today’s production against the same day in the previous year (your monitoring app typically allows date comparison). If this July 15 produced 28 kWh and last July 15 produced 40 kWh, and this year was equally sunny, investigate. Natural degradation (0.3–0.5%/year) alone cannot explain a 30% production drop.
Energy This Month and This Year (kWh): Cumulative production for the current month and calendar year. Compare against your installer’s production estimate for the same period. Most installers provide a month-by-month production estimate at installation. If January through July’s actual production is running 20% below estimate and the weather has been comparable, something is wrong.
Lifetime Energy Production (kWh): Total electricity generated since system installation. This is the number that directly correlates with your lifetime electricity bill savings. Multiply lifetime kWh by your average electricity rate to calculate total bill savings to date.
System Efficiency / Performance Ratio: Some monitoring platforms calculate this automatically. The performance ratio compares actual energy output to theoretical output at rated capacity given the actual solar irradiance received. A performance ratio of 0.75–0.85 (75–85%) is normal for a grid-tied residential system — the gap from 100% reflects inverter efficiency losses, wiring losses, temperature effects, and occasional cloud shading.
Current Status / Inverter Status: Your monitoring app shows whether your inverter is operating normally, has faults, or is offline. Status indicators vary by platform but typically use color coding: green = normal operation, yellow = warning/degraded, red = fault or offline. Check this regularly — an inverter fault can mean your system has stopped producing entirely without you noticing if you’re not monitoring actively.
Reading Panel-Level Data (Enphase and SolarEdge)
If you have Enphase microinverters or SolarEdge with power optimizers, you can see how much each individual panel is producing. This is one of the most valuable monitoring features:
Normal variation: Panels in the same string or array should produce within 5–10% of each other when receiving the same sunlight. Some variation is normal due to slight differences in tilt, minor soiling variation, and manufacturing tolerances.
Significant underperformer: If one panel is producing 30–50% less than its neighbors on the same roof section with no obvious shading difference, that panel likely has an issue — a failed microinverter (Enphase), a failed optimizer (SolarEdge), or a panel defect. This is exactly what panel-level monitoring is designed to catch.
Entire string underperforming: With SolarEdge, if an entire row of panels is producing significantly less than adjacent rows, the issue may be in the string wiring, a connection, or a wiring segment rather than individual panels.
Shading pattern analysis: If you know a particular panel gets shaded by a chimney or vent pipe in the morning, you can verify this in the historical data — the panel should recover to normal production once the shade clears. Persistent underperformance that doesn’t match expected shading patterns indicates a problem.
How to Benchmark Your System’s Performance
The most useful benchmark for your system is NREL’s PVWatts Calculator at pvwatts.nrel.gov. Enter your address, system capacity (kW DC), array type, tilt angle, and azimuth. PVWatts produces month-by-month production estimates based on decades of historical weather data at your location.
Compare your actual annual production (from your monitoring app) against PVWatts’ estimate for your system specs. A well-functioning system should produce within 10% of the PVWatts estimate. If you’re consistently 15–25% below PVWatts:
First, check if PVWatts has the right system specs. Small errors in azimuth, tilt, or DC capacity can meaningfully affect the estimate. Enter the exact values from your installation permit or as-built drawings.
Second, check for shading that wasn’t present at installation — trees grow. A tree that added significant canopy since installation could explain a year-over-year production decline.
Third, check for soiling or panel damage — do a visual inspection from the ground with binoculars. Bird droppings, accumulated pollen, or fallen debris on panels reduces production.
If the above don’t explain the gap, call your installer. Persistent underperformance of 15%+ relative to PVWatts is a service issue worth investigating.
Setting Up Alerts and Notifications
All major monitoring platforms support email or push notification alerts for system faults, prolonged zero production, and underperformance thresholds. Set these up during installation:
Fault alerts (critical): Get notified immediately if your inverter reports a fault or goes offline. An unnoticed fault could mean weeks or months of zero production without you realizing it — particularly a risk if you don’t check your app regularly.
Daily production summary: A morning email with yesterday’s production kWh is a lightweight way to stay aware of system performance without checking the app constantly.
Underperformance alerts: Some platforms allow you to set a threshold — “alert me if daily production is more than 20% below expected.” These require calibrating the expected production setting correctly, but can be valuable for automatic performance monitoring.
Frequently Asked Questions
How do I know if my solar panels are working correctly?
Check your monitoring app midday on a clear, sunny day. Your system should be producing close to its rated capacity (within 10–15%). Also verify that your electricity bill is showing the expected reduction — most billing systems show your net consumption after solar production. If your bill isn’t lower than before solar, either the system isn’t producing as expected or your usage increased.
Why does my solar production vary so much day to day?
Normal variation reflects daily weather differences. A clear, cool day in spring produces maximum output. A hot, hazy, partly-cloudy summer afternoon may produce 40–60% less. Seasonal variation is even larger — December production is typically 40–60% of June production in most US locations due to shorter days, lower sun angles, and more cloud cover. This seasonal variation is expected and accounted for in annual production estimates.
What should I do if my monitoring app shows zero production during daylight?
First, verify the monitoring system itself is online (connectivity issues can cause false zero readings). Then check your inverter physically — it should have status lights on the front. A fault or error code indicates the inverter has stopped. A grid outage automatically shuts down grid-tied inverters (anti-islanding protection). If none of these explain zero production, call your installer.
Can I monitor my solar system without the manufacturer’s app?
Yes — devices like the Emporia Vue 3 or Sense Energy Monitor connect directly to your electrical panel and monitor all power flows (solar production, grid import, grid export, and individual circuits) independently of your inverter’s monitoring platform. These provide more comprehensive household energy data and are useful if your inverter’s monitoring connectivity has issues or if you want a single dashboard for all energy flows.
Summing Up
Your solar monitoring app is one of the most valuable tools for protecting and maximizing your solar investment. Check it weekly rather than daily to spot trends without getting caught up in day-to-day weather variation. Compare your monthly production against your installer’s estimates and against prior-year data. Set up fault alerts immediately so you don’t miss a system outage. And if your actual annual production falls more than 15% below the PVWatts estimate for your system, investigate — it’s worth the call to your installer. For any questions about your solar system’s performance or for a new installation quote, call (855) 427-0058.
Updated