Do Solar Panels Need Servicing?
Author: Steve Fairless
Originally Published: 13th April 2024 · Updated: 29th August 2026
Solar panels are low-maintenance, but a complete solar PV system can still benefit from professional servicing. The modules have no moving parts, yet the installation also includes DC cabling, connectors, isolators, mounting hardware, inverter equipment, protective devices and monitoring. Those parts can develop faults that are not obvious from the ground.
At Sustainable Energy Engineering, we separate routine homeowner checks from professional diagnostics. The important point is that there is no single servicing interval that is correct for every installation. System size, building use, access, insurer requirements, fault history and manufacturer instructions all matter.
Updated: 29th August 2026 using the current March 2026 MCS maintenance schedule, Energy Saving Trust maintenance guidance, HSE roof-safety guidance and IEA PVPS reliability research.
The Current MCS Position in One Sentence
MIS 3002 Issue 6.0 provides an advisory maintenance schedule with customer visual checks, intermediate contractor visits and full contractor visits; it also states that the actual checks and frequency depend on system size, building use, roof access and stakeholder requirements such as insurers.
Servicing Is Different from Cleaning
Cleaning addresses dirt on the module surface. Servicing looks at the wider electrical and mechanical system. A clean array can still have an inverter fault, a damaged connector, water ingress, a loose mounting component or a string whose electrical readings have changed.
Conversely, a healthy system does not need invasive electrical work simply because a calendar date has arrived. Good servicing is risk- and evidence-led.
What Does the 2026 MCS Maintenance Schedule Actually Say?
The current MIS 3002 standard groups maintenance into three levels: customer visual checks, an intermediate visit by an MCS contractor and a full visit involving more specialist tests. The frequency table is explicitly described as advisory.
| Building / system context | Customer visual checks | Intermediate contractor visit | Full contractor visit |
|---|---|---|---|
| Privately owned domestic | 1 year | 10 years | 15 years |
| Domestic rented | Not specified in the table | 5 years | 10 years |
| Public building | 6-monthly | 1 year | 5 years |
| Commercial / industrial | Monthly | 1 year | 2 years |
These are not universal legal service intervals. MCS states that the checks and frequency are advisory and may need to change with system size, occupancy, roof access and other stakeholder requirements.
What an Intermediate Solar Service Can Check
The MCS maintenance schedule includes a much broader set of checks than simply looking at whether the panels are dusty. Depending on the installation and scope, an intermediate visit can include:
- AC and DC isolator condition and operation.
- DC junction boxes, fuses and surge protection where present.
- Actual generation compared with the expected prediction.
- Inverter mounting, ventilation, water ingress and fault logs.
- AC voltage at the inverter and potential over-voltage risk.
- DC connector security and damage.
- Cleaning where shallow pitch or the environment makes it necessary.
- DC circuit testing, cable condition, labels and emergency shutdown information.
What Makes a Full Service Different?
A full visit can go further into the mechanical and electrical health of the installation. The current MCS schedule adds checks such as module-clamp security, mounting rails and brackets, string series resistance, insulation resistance, potential-induced degradation testing and thermography for faulty components or module cells.
Not every domestic system needs every specialist test at every visit. The correct scope should be chosen from the system age, symptoms, equipment, previous findings and risk profile.
Why Diagnostics Matter Even When the Panels Look Fine
IEA PVPS Task 13's current failure material covers failure modes that can affect module reliability and performance, including cell cracking, glass problems, backsheets and other degradation mechanisms. Many system problems are therefore not something a homeowner can confidently diagnose from street level.
Signs Your Solar System Should Be Checked Before the Next Routine Visit
We would not wait for a scheduled service if the system is telling you something is wrong. Early investigation is sensible when you see:
Call an Engineer If You Notice
- A new inverter fault or recurring error code.
- Zero generation during daylight when the system should be active.
- A persistent step-change in output that weather and shading do not explain.
- Low-insulation, earth-leakage or RCD-related faults.
- Burning smells, heat damage or discoloured electrical equipment.
- Water ingress around electrical equipment.
- Damaged cables, exposed connectors or loose equipment.
- Visible module movement, cracked glass or mounting distortion.
What Homeowners Can Safely Check Themselves
MCS includes customer checks as visual only. From a safe position, a homeowner can look for slipped or damaged modules, obvious soiling, inverter fault indications, structural distress and new vegetation shading. Monitoring can also confirm that generation is accumulating over time.
Those checks do not require opening enclosures, unplugging DC connectors, testing live circuits or walking on a roof.
Roof Access Is Not a Routine DIY Service Task
HSE guidance states that all roof work is highly dangerous and must be properly planned. If a panel, cable or roof fixing cannot be assessed safely from ground level, use someone competent with appropriate access and fall protection.
How Cleaning Fits into a Service Plan
Energy Saving Trust's current guidance says rooftop systems generally require little maintenance and rainfall often removes much of the normal dirt. It suggests checking panels periodically and cleaning when visible build-up warrants it, with frequency depending on dust, trees, birds and the installation environment.
That means professional servicing should not automatically include an aggressive annual clean whether the modules need it or not. Cleaning should be justified by condition, access and manufacturer guidance.
What About Inverter Servicing?
The inverter is one of the most informative parts of a solar system because it records operating data and fault logs. A service may check that it is securely mounted, adequately ventilated, free from water ingress and operating within acceptable electrical conditions.
A fault log can also help distinguish a grid-voltage issue, insulation fault, intermittent shutdown or genuine inverter failure from normal weather-related variation.
Do Batteries Need to Be Included in a Solar Service?
If the property has storage, it should be considered as part of the wider energy system even though the battery has its own manufacturer requirements. A service may review alarms, firmware, operating temperatures, communications, charge behaviour and any integration issues.
If storage is being added to an older PV system, our battery retrofit service can assess compatibility rather than assuming the existing inverter, cabling and protection are suitable.
Servicing a System Installed by Another Company
Customers sometimes contact us because the original installer no longer trades, the monitoring has stopped working or a fault has appeared years after installation. In that situation, useful documentation includes the original design, commissioning sheets, inverter model, module datasheets, DNO paperwork, MCS certificate and any previous service reports.
If records are incomplete, a competent engineer can still inspect and test the installation, but diagnosis may take longer because the original design intent is less clear.
Do You Need an Annual Professional Service?
Not automatically for every privately owned domestic PV system. The current MCS table does not prescribe an annual intermediate contractor visit for a typical privately owned domestic installation; it lists annual customer visual checks and much longer advisory intervals for contractor visits.
However, a more frequent professional schedule can be appropriate after a fault, for complex systems, difficult environments, insurer requirements, commercial/public buildings, ageing equipment or where the manufacturer specifies it.
Our Servicing Approach
We prefer evidence over routine box-ticking. If a system is healthy, we document that. If the monitoring, electrical tests or physical inspection show a problem, we investigate the cause and explain the remedy. The objective is safe, reliable generation — not to sell a service visit that the system does not need.
When to Book a Solar Service
If you have a fault, an unexplained performance drop, an ageing system or no reliable maintenance history, contact our solar engineering team. We can advise on the appropriate scope rather than applying a one-size-fits-all checklist.
If you are still at the installation stage, our domestic solar design process includes handover information so you know what should be monitored and maintained from day one.
What a Useful Service Report Should Leave You With
A professional visit should produce more than a verbal “everything looks fine”. The useful output is a record of what was inspected, what was tested, any fault codes or abnormal readings, what maintenance was completed and what should be monitored next.
Where electrical tests are carried out, the report should identify the circuits or strings tested and the findings. Where no fault is found, that is still useful evidence because it creates a baseline for later comparison. Where a defect is found, the report should separate immediate safety work from recommended improvement work so the customer understands the priority.
This documentation also becomes valuable if the property is sold, the system warranty is queried, an insurer asks about a fault, or another engineer works on the installation later.
Servicing After Other Work on the Property
A service is also sensible after work that could have disturbed the PV system, such as roof repairs, scaffold strikes, inverter replacement, consumer-unit changes or alterations around existing solar cabling. The aim is not to assume damage occurred; it is to confirm that protective devices, labels, wiring routes and generation still match the intended installation after other trades have worked nearby.
