Monitoring output, normal aging, cleaning, animals, storms and inverters: a practical maintenance plan for home solar, from NREL and panel makers' manuals.
By the SolarCleaningRated team · Facts checked against the sources listed below on November 1, 2026. General information, not professional advice.
For a home system, maintenance mostly means watching what it produces, keeping it clean enough, keeping animals out of the wiring, and getting it checked when something changes. The best-practice guide for solar operation and maintenance from the National Renewable Energy Laboratory (NREL), Sandia National Laboratories and the SunSpec Alliance says the best preventive maintenance for inverters is to perform the maintenance the manufacturer requires, and panel makers set their own expectations too: Maxeon's manual says a trained Maxeon dealer or support personnel should inspect all modules annually for safe electrical connections, sound mechanical connections and freedom from corrosion.
Your inverter or monitoring app is the most useful maintenance tool you have. Check it regularly, and compare each month with the same month last year rather than with last week.
For a benchmark, NREL's PVWatts calculator estimates the energy production of grid-connected solar systems from the location and system details you enter. NREL notes that the current version's estimates may differ from the previous version's, so treat any figure as a guide rather than a guarantee. What changes in output can mean:
Cleaning is maintenance only when dirt is costing you output. NREL's guide says module soiling can often be traced to a source, such as dust from a construction site, which in its example caused a loss of about 5 percent, and suggests scheduling cleaning after the end of pollen season. Citing a 2014 study by Naeem, it gives cleaning costs of $0.25 per square meter for large systems to $1 per square meter for single residential systems. That study, an Arizona State University master's thesis, assumed soiling from dust alone measured at a Mesa, Arizona test site, cleaning prices of $2, $1 and $0.50 per module and electricity at 9.5 to 13 cents per kWh, and concluded that hiring a company to clean the residential, commercial or utility-scale systems it modelled could not be economically justified.
When you clean, follow the panel maker's instructions. NREL's guide describes plain demineralized water and a mild detergent the manufacturer recommends, and says not to use high-pressure water, brushes, solvents, abrasives or harsh detergents. Our step-by-step cleaning guide has the details and where manufacturers differ.
NREL's guide says bird populations are a source of soiling and leave nests that need removing; that where cables are buried, failures are typically caused by rodents chewing on them; and that where animals such as squirrels can reach the wiring, measures are needed to keep them out. For rooftop arrays it suggests closing gaps where birds can nest, sealing the space under the panels with bird netting all the way around, adding spikes along the top edge, and timing nest removal around the nesting season. Our bird proofing guide explains the rules on nests.
After hail or high winds, look over the array from the ground and check the monitoring app. Don't touch a damaged panel. Maxeon says that if the front glass is broken or the backsheet is torn, contact with any module surface or the frame can cause electric shock, and that damaged modules should be disconnected from the electric system immediately; REC warns that the shock risk from damaged panels is higher when they are wet. Call your installer, and your insurer if a storm caused the damage.
Inverters need their own care. NREL's guide says the best preventive maintenance is the manufacturer's required maintenance; that inverter air filters take in dust in windy or dusty conditions, so filter cleaning or replacement should follow dusty periods; and that replacement is preferred over repair when repair parts become hard to source and desired new features call for an upgrade. A table in its 2018 edition put the 20-year replacement cost at $0.25 per watt for string inverters (estimated as twice the factory price) and $0.40 per watt for microinverters. Keep the inverter warranty alongside your panel warranty, and note when each one ends.
Some of the easiest ways to lose warranty cover are maintenance mistakes. REC says its warranty is only valid if the instructions in its installation manual are observed at all times, and that it does not provide warranty for the application of any sprays or treatment. Maxeon says standing on, dropping or scratching its modules may damage them and void the warranty, as can cleaning with harsh materials such as scouring powder, steel wool, scrapers or blades. Before anyone works on the array, whether a cleaner, a roofer or a bird-proofing company, make sure they know what your panel maker allows.
If the roof under the panels needs replacing, the system has to come off and go back on. In the San Diego area, a policy from the local chapter of the International Code Council says a permitted system can be removed and reinstalled under a permit from the local building department, with the work done by qualified personnel such as a C-46 solar or C-10 electrical contractor. Our guide to solar panel removal and reinstall covers licensing and permits in California, Arizona and Nevada.
A little. An NREL review of nearly 2,000 measured degradation rates found a median of 0.5 percent a year. A sudden or large drop is not normal aging and needs checking.
Some makers say so. Maxeon's manual says a trained Maxeon dealer or support personnel should inspect all modules annually, and NREL's guidance is to follow the manufacturer's required maintenance.
Only when dirt is costing you output. REC recommends cleaning when dirt can be seen on the glass, and NREL's guide suggests cleaning after pollen season and tracing soiling to sources such as construction dust.
Your installer's estimate is one benchmark. NREL's PVWatts calculator is another: it estimates the energy production of grid-connected systems from the location and system details you enter.
41 companies in 5 areas, scored by the same published criteria.