Owning a plant · India
Solar plants rarely fail dramatically. They quietly underperform, because there is no warning light for a dirty array, a corroding earth connection or a tree that has grown. A plant losing fifteen per cent looks exactly like a healthy one.
The regime
| Interval | Task | Why |
|---|---|---|
| Monthly | Record generation; look at the glass | The only way to notice a slow decline |
| As needed | Clean when visibly dull, and after dust storms | Soiling is the largest controllable loss |
| Twice yearly | Check structure fasteners, cable ties, cable routing | Sun and heat degrade insulation and ties; fixings work loose |
| Yearly | Earthing continuity, enclosure seals, inverter vents | Safety, and the commonest cause of quiet faults |
| Yearly | Reassess shade — trees grow, neighbours build | New shade is a real and reversible loss |
| Once in plant life | Budget an inverter replacement | Shorter service life than the modules |
Last reviewed
Every other item on this page depends on one habit: knowing what your plant generated each month. Take the figure from the inverter display or monitoring app and write it down.
Compare each month against the same month last year, not against last month. Seasonal variation in India is large — a June figure well below May's is normal, not a fault — so month-on-month comparison produces false alarms and hides real ones. Year-on-year comparison for the same month removes the seasonality and leaves the signal.
A sustained unexplained drop against the same month a year earlier is your prompt to investigate, in this order: is the glass dirty, has new shade appeared, is one string producing less than its siblings, and is the inverter reporting anything. In the first year you have no comparison, so compare against the annual generation figure the installer's projection assumed — and if they never gave you one in writing, ask for it now.
Soiling is the largest controllable loss on most Indian roofs. Dust cuts the light reaching the cells continuously, and because the decline is gradual nobody notices. It is worse in arid and industrial areas, after harvest burning in parts of the north, and anywhere construction is active nearby.
Uneven soiling can be worse than uniform soiling: a heavily soiled section of a string can drag output down by more than its share, in the same way partial shade does. So patchy bird droppings or a dust drift along one edge deserve attention even when the array broadly looks fine.
Frequency should come from observation rather than a generic sheet. A quiet residential street in a wet region may need attention every couple of months; a dusty location can lose meaningful output within weeks. Monthly inspection with cleaning when the glass looks dull is a sensible default.
Three safety rules are non-negotiable. Never walk on modules — the damage is often invisible cracking rather than obvious breakage, and it permanently reduces output. Never put cold water on hot glass, because thermal shock can crack it; clean early in the morning before the roof heats up. And never work at height without proper footing. Water-scarce regions need a method that does not assume a running hose: a soft dry brush or microfibre sweep does most of the work, with a rinse reserved for after a dust event. Regional specifics are in Rajasthan and Ludhiana.
The inverter, first and most often. Modules commonly carry performance warranties measured in decades and usually outlast everything around them. Inverters are electronics working hot on a roof, with a materially shorter service life. You should plan on buying at least one replacement during the plant's life and put it in your payback arithmetic from the start, rather than meeting it as a surprise in year seven. Placement helps: a shaded, ventilated location rather than a sun-baked wall genuinely extends life.
The DC side, second. Connectors and cable insulation degrade under sun and heat, cable ties perish and drop cables onto hot surfaces, and rodents chew what is left accessible. These faults are hazardous as well as costly, and they are found by inspection rather than by waiting for a failure.
Earthing and fixings, third. Corroding or loosening earth connections are a safety matter, not a performance one, and matter more in humid and coastal air — see Guwahati for what sustained humidity attacks first. Mounting fasteners work loose under thermal cycling and wind, and a loose structure becomes a wind-loading problem.
Modules, rarely. When they do fail it is usually physical: impact, hail, or cracking from someone standing on them.
These are routinely conflated in sales conversations. A warranty is a promise about defects; maintenance is the work that keeps the plant producing. A warranty does not clean your panels, does not tighten your structure, and typically does not cover damage arising from inadequate maintenance — which is worth reading carefully, because it means neglect can void the protection you were relying on.
Also check what a warranty excludes: lightning and surge, rodent damage, and consequential losses are common carve-outs, and workmanship cover usually comes from the installer rather than the manufacturer, which makes the installer's survival relevant. That distinction is explored in Nagpur, where heat shortens equipment life.
Get scope in writing rather than accepting a headline annual price:
That last point is not cynicism. Service reach matters more outside the metros, and a twenty-year promise is worth only as much as the travel to your roof.
The best time to protect your generation is before installation. Insist the layout leaves safe access to every module from a standing position — an array crammed against a parapet to fit one more panel is an array that quietly stops being cleaned. Ask for the inverter in a shaded, ventilated, reachable spot. Get waterproofing at every penetration written into scope. And be honest about shade that will grow, rather than assessing only today's outline.
Not installed yet? The free home check covers layout and access alongside the economics, because both decide your ten-year output. Related: how rooftop solar works · warranty & lifespan · costs & payback · ALMM & DCR · mono vs poly.
There is no single correct interval, because it depends on what settles on your roof. A quiet residential street in a wet region may need attention only every couple of months, while a dusty industrial or arid location can lose meaningful output within weeks. A reasonable default is monthly inspection with cleaning when the glass is visibly dull, plus a clean after any dust storm or the end of a long dry spell. Set the interval from observed output rather than from a generic maintenance sheet.
By tracking monthly generation, because nothing else will tell you. There is no fault light for a dirty array, a degraded connector or one shaded string, and a plant losing fifteen per cent looks and sounds exactly like a healthy one. Record monthly units from the inverter display or monitoring app and compare each month against the same month last year rather than against the previous month, since seasonal variation is large. A sustained unexplained drop against the same month a year earlier is your signal to investigate.
The inverter, by a wide margin. Modules commonly carry performance warranties measured in decades and usually outlast everything around them, while inverters are electronics working hot on a roof and generally have a shorter service life, so you should plan on buying at least one replacement during the plant's life and include it in your payback thinking. After that, the usual culprits are DC-side connectors and cable insulation degrading in sun and heat, loose or corroding earthing connections, and mounting fasteners working loose.
Get the scope in writing rather than accepting a headline price. It should state how many visits per year, whether panel cleaning is included or only inspection, who supplies water and access equipment, whether the inverter is inspected and its filters or vents cleaned, whether earthing continuity and structural fasteners are checked, what the response time is for a fault, and what is explicitly excluded. Also ask whether monitoring is included or a separate subscription, and what happens to the contract if the installer ceases operating.
Often yes for an accessible ground-floor or low terrace array, with a soft brush or microfibre and a gentle rinse, done early in the morning. Three rules matter. Never walk on modules, because the damage may be invisible cracking rather than obvious breakage. Never put cold water on hot glass, since thermal shock can crack it, so clean before the roof heats up. And never work at height without proper footing. If reaching the array involves a risky climb, that itself is a design problem worth fixing rather than a routine to accept.
Enough to matter, and it is the largest controllable loss on most Indian roofs. Dust reduces the light reaching the cells continuously and silently, and the loss compounds because nobody notices a gradual decline. It is worse in arid and industrial regions, after harvest burning in parts of the north, and wherever construction is active nearby. Uneven soiling can be worse than uniform soiling, because a heavily shaded portion of a string can drag down more than its share of the output.
Gradual degradation of well-made modules is typically stated in fractions of a per cent per year, and manufacturers usually warrant a minimum retained output after twenty-five years. In practice this slow decline is far smaller than the losses from soiling, shade that has grown over time, or a fault nobody noticed. Which is the useful conclusion: maintenance and monitoring protect your generation much more than module choice does.
