When Your Installer and Inverter Vendor Blame Each Other, Here's What to Do

It's one of the most frustrating experiences in home solar ownership: something is clearly wrong with your system's production, but every company you contact says it's the other company's problem.

The installer says the inverter is at fault. The inverter company says the system was installed incorrectly. You're stuck in the middle, losing money with each passing month, while the parties who owe you a solution are busy pointing at each other.

This isn't a rare edge case. It's one of the most common patterns in residential solar disputes. And it has a solution — but you need to understand the underlying contract structure to use it.

Why This Pattern Is So Common

App Store reviews of major solar monitoring platforms from 2025 and 2026 are full of this exact complaint. The pattern that fills those reviews: the installer blames the inverter firmware; the vendor says the installer misconfigured the system; months pass and nothing is fixed.

This pattern emerges from a structural misalignment: the installer and the equipment manufacturer have separate incentives, separate contracts, and separate definitions of success. Neither has an obvious reason to take ownership of a problem that might be the other party's fault — especially when a homeowner doesn't yet have documentation that makes either party's responsibility undeniable.

Two Contracts, Not One: The Legal Structure That Matters

To break out of the finger-pointing loop, you need to understand that your solar installation involves at least two separate contracts:

You signed a contract with your installer. That contract includes a production guarantee — a promise that your system will produce X kWh per year. Your installer is the counterparty to that promise.

Your installer signed a contract with the equipment manufacturer. That contract includes equipment warranties. If the inverter fails and reduces production, the installer's remedies against SolarEdge are in that second contract — not in your contract.

This means: when your installer says "it's a SolarEdge issue, talk to them," they're asking you to act on their behalf in a dispute that's theirs to manage. You don't need to. The production guarantee you signed is between you and the installer.

Tier 1: Separate the Production Claim from the Equipment Claim

Keeping these two tracks separate in writing is important. When you mix them — "my system isn't producing enough because of the inverter issue" — you give the installer room to say "we're working on the inverter warranty, so there's nothing else to address." Those are two different problems that require two separate resolutions.

Tier 2: Making the Installer Accountable for the Production Guarantee

Send a written communication to your installer that separates the two tracks explicitly:

"I am writing to formally document two separate issues with my solar system. First, a production shortfall: my system has produced [X kWh] over [period], against a guarantee of [Y kWh]. I am requesting that you address this production shortfall per Section [X] of our contract. Second, separately, I understand there may be an inverter issue that contributed to the shortfall. I would like a status update on that equipment matter as well — but I want to be clear that resolving the equipment issue does not resolve the production shortfall claim, which is a contractual matter between us."

This structure is harder to deflect. The installer can't say "we're working on the SolarEdge issue" and consider the matter closed — you've explicitly separated the production claim as a distinct outstanding item.

Tier 3: Making the Manufacturer Accountable (When Relevant)

In most production shortfall cases, you don't need to deal with the equipment manufacturer directly — the installer is responsible for delivering the guaranteed production regardless of what equipment they used.

However, there are situations where a direct equipment warranty claim makes sense:

• Your system is producing to guarantee, but specific components have failed and need replacement under their warranty
• Your installer is unresponsive or out of business, and you need to pursue equipment replacement directly
• You have a lease or PPA and the equipment warranty is one of the few remedies available to you

For equipment warranty claims, you'll need: proof of purchase (from your installer), the exact model and serial number of the failed component, and documentation of the failure. Inverter manufacturers typically handle these through their support portals.

Documentation That Ends Finger-Pointing

The practical reason the installer-vs-manufacturer standoff persists is that it's easy to maintain ambiguity without structured data. "My system seems slow" is an argument. "My system produced 14,200 kWh in the 12 months ending April 2026, against a guaranteed 16,800 kWh, a 15.5% shortfall that would have required 152 additional kWh/month of solar-grade weather to explain" is not an argument — it's a calculation that requires a response.

The documentation package that ends this dispute contains:

1. Time-stamped production data — monthly production from your monitoring system, covering the entire claim period
2. Weather-adjusted shortfall calculation — production compared to a weather-adjusted baseline, so neither party can blame weather variation
3. Original contract excerpt — the specific guarantee number and methodology clause
4. Your claim calculation — dollar value of the shortfall at your applicable utility rate

A Composite Walkthrough

To illustrate how this plays out in practice, consider a composite example drawn from common dispute patterns:

A homeowner in the Southwest notices their electricity bills haven't dropped as much as their installer projected. Six months in, they contact their installer (a large national company). The installer reviews the monitoring data and attributes the issue to "optimizer performance variability" — implying a hardware issue. The homeowner contacts the inverter vendor. The vendor's support team reviews the system remotely and notes that "the system appears to be operating within spec" — meaning, individually, each component is passing its own tests.

The homeowner is stuck. Both parties' statements are technically true but don't address the production shortfall.

What breaks the deadlock: the homeowner generates a structured report showing 6-month cumulative production vs. the contract guarantee number, weather-adjusted to that period's irradiance. The report shows a 12% production shortfall that can't be attributed to weather. The installer can no longer claim the system is "operating within spec" relative to the guarantee — those are different claims. The debate shifts from whether a problem exists to who fixes it — the conversation the homeowner needed.

The key shift: moving from "I think my system is underperforming" to "here is the measurement against your contract promise."

Related Guides

• Solar Underperforming? Here's Who to Actually Call — the general escalation guide
• How to File a Production Shortfall Claim — step-by-step claim submission
• My Solar Isn't Producing What Was Promised: A Step-By-Step Guide