HyreSolar tools
The one part of a solar system that is expected to be replaced inside the panels' warranted life.
Panels are commonly warranted for 25 years. Many string inverters are not. That difference creates a window in which the array is still under warranty and the thing converting its output is not — and almost no solar proposal shows you where that window falls. This tool finds it from your own paperwork.
What this returns for a typical 2019 string-inverter system
A system switched on in 2019 with a 12-year inverter warranty is covered to 2031 — five years from now — and then runs 13 years uncovered while the panels are still under a 25-year warranty. Change nothing except the inverter type: microinverters warranted 25 years close the gap entirely. The gap is a function of which inverter was installed, not of how the system performs.
Last updated . Data as of 5 September 2026.
Two figures off your own paperwork. Money outputs stay blank until you enter a real quote.
A warranty calendar, not a reliability forecast. Equipment often outlives its warranty.
Your own warranty certificate is the only authority here. HyreSolar does not sell or service inverters.
The gap is not a prediction that your inverter will fail. It is the number of years in which, if it does fail, the bill is yours. Equipment frequently outlives its warranty and occasionally dies inside it. What the warranty term tells you is where the manufacturer stopped being willing to carry the risk, which is a useful signal about design life even though it is not a forecast.
This is the cost most payback models leave out. A simple payback calculation — ours included — stops at the break-even year and never asks what happens in year 13. If your break-even lands near your warranty cliff, the two numbers are worth looking at together, because a replacement arriving just after break-even resets part of the clock.
A gap of zero is a real answer, not a failure to compute. If your inverter warranty matches or outlasts the panel warranty, you have no uncovered window, and the honest output is to tell you so rather than manufacture a concern.
Every input below is a number you can find, not one you have to guess. This is where each one comes from.
Not the contract date and not the installation date if they differ. Warranty terms usually run from commissioning or from purchase, and the difference can be months.
Where to find it Your permission-to-operate letter from the utility, or the first bill that shows an export credit. See what permission to operate is.
Read it off the certificate. We do not publish a table of manufacturer terms, because terms vary by model, region and purchase date, and a table would be wrong for a large share of readers.
Where to find it The inverter warranty certificate in your handover pack, or the manufacturer’s warranty document for your exact model number. The model number is on the label on the unit itself.
Some string inverters ship with a shorter standard term that can be extended, usually only at the time of installation. If an extension was bought, the certificate shows the extended term — use that.
Where to find it Your original contract, under equipment or options. An extension bought later, if the manufacturer allows one at all, will have its own paperwork.
This sets the far edge of the window. It is the product warranty for defects, which is a different thing from the performance guarantee about output.
Where to find it The panel warranty certificate. Note that panels typically carry two warranties — product and performance — with different lengths. Use the product one here.
This field starts empty on purpose. HyreSolar does not publish a replacement price, because we could not verify one against a primary source, and a made-up figure is worse than no figure.
Where to find it Ask your installer, or any local solar service company, what a like-for-like replacement of your specific model would cost fitted. Prices vary by inverter class and by market.
It divides your quote by the years of cover remaining. It is a savings target, not a prediction of when you will spend it.
Where to find it Nowhere — the tool computes it. Treat it as the amount per year that turns a lump-sum surprise into a planned expense.
Install year + inverter warranty term. Nothing more sophisticated, because nothing more sophisticated is defensible.
Expiry year minus the current year. Negative means you are already past it, which the tool says plainly.
Panel warranty term minus inverter warranty term, floored at zero. This is the uncovered window.
Replacement cost ÷ years of cover left. A sinking fund, not a forecast.
The formula, in full
expiry = install year + inverter warranty years. cover remaining = expiry − 2026. gap = max(panel warranty years − inverter warranty years, 0). sinking fund = replacement quote ÷ years of cover remaining.
A system commissioned in 2019 with a string inverter carrying a 12-year warranty, under panels carrying a 25-year product warranty. The homeowner has since obtained a replacement quote of $2,400 fitted for their 8 kW system.
Inputs
Result
13 years uncovered, $480/yr to fund it
The array is warranted until 2044. The inverter is warranted until 2031. From 2031 the homeowner owns the replacement risk on a system that still has thirteen years of warranted panel life in front of it. Setting aside $480 a year for the five remaining covered years turns a $2,400 surprise into a funded line item. At 8 kW that quote is $0.300/W — a useful figure to compare against a second quote, since inverter replacement is one of the few solar costs where a like-for-like comparison is genuinely easy.
The same 2019 system, one input changed at a time. Every figure is computed by the calculator on this page.
| Change | Cover ends | Remaining from 2026 | Uncovered window |
|---|---|---|---|
| Base case2019 install, 12-year inverter, 25-year panels | 2031 | 5 years left | 13 years |
| Microinverters warranted 25 years | 2044 | 18 years left | no gap |
| String warranty extended to 20 years | 2039 | 13 years left | 5 years |
| 10-year inverter warranty | 2029 | 3 years left | 15 years |
| Installed 2014 instead of 2019 | 2026 | expires this year | 13 years |
| Installed 2024 instead of 2019 | 2036 | 10 years left | 13 years |
| Panels warranted 30 years not 25 | 2031 | 5 years left | 18 years |
Note which input actually closes the gap. Moving the install year five years in either direction changes when the cliff arrives but never changes its width — the window stays 13 years. Only the inverter warranty term closes it: 25-year microinverters take it to zero, a purchased extension to 20 years takes it to five. The gap is decided on the day the equipment is chosen, and by nothing that happens afterwards.
Ranked. A proposal can change any of these without saying anything untrue, so these are the inputs to check first.
The only input that changes the width of the gap. Microinverters are commonly warranted to match the panels; string inverters commonly are not. This is decided at the proposal stage and is effectively permanent afterwards.
Most extended inverter warranties can only be purchased at or near the time of installation. If you are reading this years later, that option has usually closed. Taking a 12-year term to 20 cuts the window from 13 years to 5.
Moves when the cliff arrives, never how wide it is. Useful for planning, useless for avoiding.
Sets the far edge. A 30-year panel warranty against a 12-year inverter is an 18-year window, which is a longer uncovered period than most people realise they signed up for.
Failure rates, mean time to failure, degradation, monitoring hardware, optimisers and the labour share of a replacement. We model the warranty calendar, which is a documented fact about your equipment, rather than a reliability forecast, which is not.
It is neither a promise the unit will last that long nor a prediction it will stop. It is the period the manufacturer is willing to carry the cost. Plenty of inverters run well past it.
Panels usually carry both, and they are different lengths covering different things. The performance warranty is about output falling below a curve; the product warranty is about defects. Use the product term here.
A warranty claim usually runs through the installing company, and solar installers close. If yours has gone, the claim path is the manufacturer directly, which is slower and sometimes narrower. See what to do when your installer is gone.
A replacement quote should be fitted, not supply-only. The unit is one line; the visit, the disconnection, the commissioning and the utility notification are others.
Twelve years is a long time in inverter models. A replacement may be a different unit needing different mounting, different comms, or a re-registration with the utility. Ask whether your model is still supported before you assume the swap is simple.
A 25-year inverter warranty is only as good as the company standing behind it in year 20. The term is a contract, not a guarantee of corporate survival.
We will not print a number, because a credible one would need a failure distribution for your specific model and we do not hold one. What we can tell you is where the manufacturer stopped carrying the risk, which is the warranty term on your certificate, and that is what this tool works from. Treat anyone quoting a confident average lifespan without naming a dataset with the scepticism it deserves.
Because we could not verify one against a primary source we can cite, and inventing a plausible-looking figure would be worse than leaving it blank. Inverter replacement pricing varies by class, by model availability and by local labour rates. Get a fitted quote for your specific unit and enter it; the tool will then compute your sinking fund and your $/W.
It is the number of years your panels remain under product warranty while your inverter does not. In our default case that is 13 years — from 2031 to 2044 — during which a failure is entirely your cost on a system that is otherwise still covered. It matters because it is the single largest foreseeable expense in a solar system’s middle age, and almost no proposal shows it.
Usually only at or near the time of installation, which is why it is worth asking about before you sign rather than after. Where an extension is available later it is generally more expensive and sometimes conditional on an inspection. Our scenario table shows what one buys: taking a 12-year term to 20 years cuts the uncovered window from 13 years to 5.
Where they are warranted for the same term as the panels, the arithmetic gap is zero — that is what the calculator returns. Whether that is the same as no risk is a different question: a 25-year warranty depends on the manufacturer still existing in year 24, and it does not cover labour in every case. Read the terms rather than the headline number.
Nothing urgent, and specifically not a pre-emptive replacement of a working unit. The useful steps are to check the system is reporting normally, to find out whether your model is still supported and still stocked, and to get a fitted replacement quote now so the number is known rather than discovered under pressure. A working inverter past warranty is a budgeting question, not a fault.
The new unit carries its own warranty, which typically starts at its own installation date, so the calendar restarts for that component only. It does not extend your panel warranty, your workmanship warranty or any performance guarantee. If the replacement is a different model, check whether your utility requires re-notification before it is energised.
Simple payback ignores inverter replacement entirely — ours says so in its own limits. If your payback lands at year 14 and your warranty cliff at year 12, the two are worth reading together, because the replacement arrives before the system has finished paying for itself. That does not make solar a bad investment; it makes the simple payback figure an optimistic one.
Use the date on your permission-to-operate letter from the utility, which is the moment the system was legally allowed to export. If you cannot find it, the first electricity bill showing an export credit brackets it within a month or two. Failing both, your installer or the utility interconnection record will have it.
Every assumption in this calculator is argued from primary sources somewhere in our research library. These are the pages that matter for this one.
Screens a proposed inverter against NEC 705.12 before you are quoted for a service upgrade you may not need.
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We are a research desk, not a sales floor. We read the statute, the tariff, the code section, the federal filing or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it. Where a number cannot be traced to a primary source, we publish the shorter page and say what we could not verify. That rule has cost us whole sections, and it is the reason the rest can be trusted.
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Data as of 5 September 2026. Authorship on this site is organisational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.