Solar & battery
Solar Maintenance Calculator
Works maintenance cost over a system's life, where inverters dominate it.
Result
Most payback calculations ignore maintenance entirely, which flatters the return. Cleaning matters far more in dusty or pollen-heavy areas than in places with regular rain, and panels on a low-pitched roof self-clean poorly. The inverter replacement is the item most often forgotten and the largest single cost after installation.
Get a Free Business AuditHow the calculation works
Routine items such as inspection, monitoring and cleaning, plus the expected replacement of components with shorter lives than the modules, annualised over the system's life. Modules typically outlast inverters and batteries, which means a long-term cost projection is largely a replacement schedule.
What moves the number
- Inverter expected life against module life.
- Battery replacement cycle where storage is installed.
- Cleaning frequency, which depends on soiling conditions.
- Monitoring and inspection.
Where this one goes wrong
A payback or lifetime cost calculation that assumes no component replacement over twenty-five years is understating cost by at least one inverter and, where storage is installed, at least one battery. Include the replacements. Cleaning is more marginal and site dependent: in a rainy climate with reasonable tilt it rarely pays for itself, while in a dusty or agricultural setting the soiling loss can be substantial.
Before you quote
- Include at least one inverter replacement in a long projection.
- Include battery replacement where storage is installed.
- Judge cleaning against actual soiling conditions, not generally.
Questions
About this calculator
Do solar systems need maintenance?
Little routine maintenance and real component replacement. Modules typically outlast inverters and batteries, so a lifetime cost projection is largely a replacement schedule rather than a servicing budget.
Is panel cleaning worth paying for?
It depends on the site. In a rainy climate with reasonable tilt the soiling loss rarely justifies the cost, while in dusty or agricultural settings it can be substantial. Measuring production before and after once settles it for a given site.
What does a long payback calculation usually omit?
Inverter replacement, and battery replacement where storage is installed. A twenty-five year projection with no component replacement is understating cost by at least one inverter, which materially changes the result.
The formula
lifetime = annual maintenance x years + inverter replacements x replacement cost
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How to use this calculator
- System size (kW DC). Enter your own figure; the page starts at 7.2.
- Cleaning per visit ($). Enter your own figure; the page starts at $180.
- Cleans per year. Enter your own figure; the page starts at 1.
- Inspection per year ($). Enter your own figure; the page starts at $150.
- Monitoring per year ($). Enter your own figure; the page starts at $60.
- Inverter replacement cost ($). Enter your own figure; the page starts at $2,200.
The result updates as you type, so you can try a figure, see what it does to annual maintenance, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| System size (kW DC) | 7.2 |
| Cleaning per visit | $180 |
| Cleans per year | 1 |
| Inspection per year | $150 |
| Monitoring per year | $60 |
| Inverter replacement cost | $2,200 |
| Inverter life (years) | 13 |
| Years to project | 25 |
What comes out
| Result | Value |
|---|---|
| Annual maintenance main result | $390 |
| Over the period | $11,950 |
| Inverter replacements | 1 |
| Cost per kW per year | $54.17 |
| Averaged per year including inverter | $478 |
Routine maintenance runs $390 a year. Across 25 years, including 1 inverter replacement(s), the total is $11,950, averaging $478 a year.
How sensitive the answer is
Holding everything else steady and changing only cleaning per visit, this is what happens to annual maintenance. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cleaning per visit ($) | Annual maintenance |
|---|---|
| $90 | $300 |
| $135 | $345 |
| $180 example above | $390 |
| $270 | $480 |
| $360 | $570 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- System size (kW DC)
- A number, between 0 and 5000, starting at 7.2.
- Cleaning per visit ($)
- A money amount, starting at $180.
- Cleans per year
- A number, between 0 and 12, starting at 1.
- Inspection per year ($)
- A money amount, starting at $150.
- Monitoring per year ($)
- A money amount, starting at $60.
- Inverter replacement cost ($)
- A money amount, starting at $2,200.
- Inverter life (years)
- A number, between 0 and 40, starting at 13.
- Years to project
- A number, between 0 and 40, starting at 25.
What the results tell you
| Result | What it is |
|---|---|
| Annual maintenance | The headline result. A money figure. |
| Over the period | A money figure. |
| Inverter replacements | A number. |
| Cost per kW per year | A money figure. |
| Averaged per year including inverter | A money figure. |
A design still needs a site visit
Output and sizing figures use the assumptions you enter, not measured irradiance, shading or roof orientation at your address. Real production depends on all three, plus inverter behaviour and local interconnection rules.
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