Monthly checks — 5 minutes in your monitoring app
These checks take less than five minutes and catch the majority of issues before they become serious. Your monitoring portal does most of the work — you just need to look at it.
Compare against the same month last year, or against the MCS estimate for the time of year. In the UK, a 4kW system typically generates 250–400 kWh in summer months and 80–150 kWh in winter. A sudden drop of 20%+ compared to previous years (at the same time of year) warrants investigation — shading from new tree growth, a panel fault, or an inverter error may be the cause.
Look at the inverter status in your monitoring app. Any error codes, warning indicators, or periods where the system stopped generating should be noted. Some errors are transient (grid voltage fluctuations that clear themselves) but recurring errors indicate an underlying problem. See our guide on reading inverter fault codes for what common codes mean.
If you have a battery, check the daily pattern: it should charge during solar hours (or cheap overnight hours if on a time-of-use tariff) and discharge during the evening. A battery sitting at 100% all day isn't discharging when it should. A battery sitting at 0% means it's draining completely and your reserve setting may be too low. Roughly one full cycle per day is healthy and normal.
If your monitoring app hasn't updated for a few days, the WiFi dongle or data logger may have disconnected. This doesn't affect generation (your system keeps working), but it means you can't see what's happening. Common causes: router restart, WiFi password change, dongle firmware issue. Check the WiFi light on the inverter or dongle and power-cycle it if needed.
Quarterly checks — visual inspection from the ground
Every three months, do a physical check of the equipment you can see from ground level. This catches issues that monitoring data alone won't reveal.
Look up at your panels with binoculars if needed. Check for visible dirt, bird droppings, leaves, or moss at panel edges. Look for cracked glass, browning or yellowing cells, or frames that appear loose or lifted. If one panel looks significantly different from the others, cross-reference with your monitoring data to see if output has dropped on that string.
Never climb on the roof to inspect or clean panels. Falls from height are the biggest risk with solar maintenance.
Check that nothing is blocking the inverter's ventilation — items stacked against a garage-mounted inverter is surprisingly common. Check the status LED (green = normal, red/flashing = fault). Listen for unusual sounds: a quiet electrical hum is normal, but buzzing, clicking, or grinding is not.
Check that all cable covers are secure and no exposed connections are visible. If mounted in a damp location (outside or in an uninsulated garage), check for condensation or signs of water ingress.
Check that all isolator switches are in the correct position (ON during normal operation). Occasionally, isolators get knocked — especially the AC isolator near the consumer unit if it's in a high-traffic area. A tripped or knocked isolator stops generation completely. If you're not sure where your isolators are, see our guide on how to shut down your solar system — it identifies the location of each switch and what it does.
Annual review — a deeper look
Once a year, preferably in spring before the high-generation summer months, do a more thorough review.
Your MCS certificate states an estimated annual yield. In the first year, actual generation within 10% of this figure is normal. If generation is consistently 15%+ below estimate, investigate — possible causes include incorrect export limitation settings, partial shading that wasn't accounted for, panel soiling, or inverter underperformance.
If your monitoring portal shows battery state of health, note it. A new LiFePO4 battery starts at 100% SoH. After 3–5 years, 92–97% is typical. After 10 years, 85–90% is reasonable. If SoH drops below 80% within the warranty period (usually 10–12 years), contact your installer or the manufacturer for a warranty assessment. Also check that individual battery module voltages are balanced — a module reading significantly lower than the others may have a cell issue.
Cross-reference your monitoring's total export figure against your Smart Export Guarantee payments. If there's a significant discrepancy, your smart meter may not be recording exports correctly, or the MID-approved meter used for billing may differ from your inverter's CT-based measurement. Contact your export tariff supplier if payments seem consistently low.
Tariff rates change, and your energy usage may have evolved over the year. Check whether your current import and export tariffs are still the best option. If you added a battery since you last reviewed tariffs, a time-of-use tariff may now make more sense. See the maximising your system guide for tariff strategy.
Confirm you still have access to your MCS certificate, electrical installation certificate, G98/G99 notification, panel warranty certificates, inverter warranty certificate (with serial number), and battery warranty certificate. Note when each warranty expires and set a reminder for 6 months before the inverter warranty ends — inverter replacement is the most common large expense and planning ahead avoids rush decisions.
Panel cleaning — when you need it and when you don't
This is one of the most over-sold services in the solar industry. In most of the UK, rain keeps panels clean enough to perform well. But there are situations where cleaning does make a measurable difference.
Panels at a low tilt angle (below 15°) — rain doesn't sheet off effectively
Heavy bird droppings — especially from pigeons nesting under panels
Near trees with sap or pollen buildup
Coastal areas with salt spray accumulation
Near construction sites with persistent dust
Visible performance drop in monitoring that correlates with dirty panels
Panels at a standard tilt (25–40°) — rain handles most dirt
No visible soiling when viewed from ground level
Monitoring shows generation in line with expectations
No birds nesting under or near the panels
Not near trees, roads, or construction
Studies show typical soiling loss in the UK is only 1–3% annually
Firmware updates — proceed with caution
Inverter and battery firmware updates are not like phone updates. They can change how your system operates, reset your settings, and in some cases cause more problems than they solve. Our firmware update risks guide covers this in detail, but here are the essentials.
The update fixes a specific bug you are experiencing. The update is required for a new feature you need (e.g., tariff integration, EPS capability). Your installer or manufacturer has specifically recommended it for your model and firmware version. You've backed up all your current settings first.
Your system is working perfectly and the update doesn't address any issue you have. The update has just been released and you're in the first wave of users (let others find the bugs first). You're in the middle of winter or a critical period where you cannot afford downtime. You don't have your current settings backed up. The update notes are vague or don't explain what changes.
Understanding your warranties
Your solar system has multiple warranties covering different components for different periods. Knowing what's covered and for how long helps you plan ahead — especially for inverter replacement, which is the most common major expense.
The panel performance warranty guarantees that output won't fall below a threshold (usually 80–85% of rated power) by the end of the warranty period. The product warranty covers manufacturing defects like junction box failure, delamination, or cell cracking. These are separate warranties — a panel can be within its product warranty but not its performance warranty, or vice versa.
When to call an engineer vs when to DIY
Some things you can check or fix yourself. Others need a qualified professional. Here's how to tell the difference.
Check monitoring data and identify patterns
Power-cycle the WiFi dongle or data logger
Adjust battery settings, charge schedules, and system modes in the app
Clean panels from the ground using water and a soft brush
Check and reset a tripped AC isolator
Apply firmware updates (with caution — see above)
Sign up for or change your export tariff
Visually inspect panels, inverter, and cables from ground level
Persistent fault codes that won't clear after restart
Earth fault, isolation fault, or arc fault errors
Physical damage to panels, cables, or the inverter
Burning smell, discolouration, or melted plastic near any component
Any work involving the DC isolator, DC cables, or rooftop connections
CT clamp repositioning or replacement
Inverter replacement or upgrade
Any electrical work involving the consumer unit
Suspected water ingress into the inverter or junction boxes
Related guides
Safe shutdown and restart — the correct AC and DC isolation sequence for all brands.
Settings resets, stalled updates, bricked hardware — what can go wrong and how to recover.
Battery chemistry, BMS, charge cycles, degradation, and state of health explained.
Data flow, portal figures, offline troubleshooting, and how to access monitoring after moving house.
What common fault codes mean and when they indicate a real problem vs a transient event.
Tariffs, export payments, self-consumption, and battery scheduling — get the best return.