Start with the diagnosed fault, not the age
A system that is twelve years old with a failed inverter is usually a repair. A system that is twelve years old with failing modules, degraded racking, and an inverter on its second replacement is a different conversation. The number that matters is not the age of the system but the condition of everything the failed part connects to.
That is why a recommendation to replace without a stated diagnosis should be treated as incomplete. Ask what was tested, what was ruled out, and what specifically cannot be retained.
The comparison, factor by factor
Use the same factors for both options. Comparing a repair quote against a replacement quote on price alone hides the differences that determine which one is actually cheaper over time.
| Factor | Repair scope | Replacement scope |
|---|---|---|
| Diagnosed issue | Explain the targeted correction | Explain the equipment being replaced |
| Cost | Include every required charge | Include installation and commissioning |
| Compatibility | Confirm existing components remain suitable | Document compatibility with retained equipment |
| Warranty | Identify applicable repair and existing coverage | Identify replacement coverage and exclusions |
| Roof plans | Account for upcoming access or reroofing | Coordinate with remaining roof life |
| Expected operation | State the basis of any estimate | Identify assumptions for the proposed equipment |
| Disruption | Usually hours to a day | Usually days, plus permitting and inspection |
Typical repair costs, for scale
These are planning ranges for standard residential work, not a quote. The service partner diagnoses the system on site and quotes the actual repair in writing before any work begins.
These ranges exist so a repair quote can be judged against a normal order of magnitude. They are not a bid, and they do not include the equipment replacement scenarios that require a compatibility review.
| What is wrong | Typical range | What the work involves |
|---|---|---|
| Diagnostic visit (credited toward the repair) | $150 to $300 | Monitoring review, inverter codes, connections, and a written finding |
| Microinverter or optimizer replacement | $250 to $600 per unit | Part plus roof access; units are usually replaced one at a time |
| String inverter replacement (all-in) | $800 to $1,200 | Unit, labor, permit, and re-commissioning for a standard single-inverter residential system |
| Monitoring or communications repair | $150 to $450 | Restores production reporting; does not always require roof access |
| Roof leak at a penetration or flashing | $400 to $1,200 | Roof scope; may require removing and reinstalling the affected panels |
| Storm or impact damage (per affected panel) | $300 to $700 | Panel replacement plus racking inspection; insurance documentation available |
A quote-comparison worksheet
Fill this in before deciding. It takes ten minutes and it is the difference between choosing on evidence and choosing on the larger quote's confidence.
- What exactly is being replaced, and what is being retained?
- What is the total, including permit, inspection, and commissioning?
- What is excluded, and what would change the price after the visit?
- What warranty applies to the new work, and for how long?
- What is the expected remaining life of the retained equipment?
- What happens if the repaired equipment fails again in two years?
- Is a reroof due within the next five years? If so, how does that change the sequencing?
When replacement genuinely makes sense
Replacement is a reasonable answer in a small number of situations: the system is at the end of its useful life across multiple components, compatible parts no longer exist for a system already underperforming, a reroof is due and the array must come off anyway, or the existing system has a structural or safety defect that cannot be corrected in place.
In each of those, the recommendation should be able to name the specific condition that makes repair impractical. That is a testable claim, and asking for it is reasonable.
Why this guide does not quote savings
A payback or savings figure requires your actual consumption, your utility's current rate structure, your roof's orientation and shading, and the specific equipment proposed. Without those, any number would be invented precision.
If a provider gives you a savings figure, ask for the inputs. A defensible estimate can show its assumptions and how the result changes when they move. One that cannot is marketing.