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Solar and Battery Performance Guarantees and SLAs for Commercial Sites

Guide · Commercial solar & battery · ~5 min read

A commercial solar and battery system is only as good as the guarantees behind it. Understanding performance warranties and service level agreements (SLAs) protects your investment long after the install crew has packed up.

What a performance guarantee actually promises

On commercial sites, a performance guarantee is a commitment that your system will generate or store within an expected range over time, not just a promise that the gear works on day one. It's different to a product warranty, which only covers faults in the hardware itself.

The detail matters. A guarantee should spell out how performance is measured, over what period, and what happens if the system falls short. Vague wording is where disputes start, so look for clear, testable terms.

• Expected output or storage performance, usually assessed against a benchmark
• The measurement method and reference conditions used
• The remedy if performance drops below the agreed level
• How long the guarantee runs and what can void it

Product warranty vs performance warranty vs workmanship

Three separate guarantees usually sit behind a commercial install, and they often have different terms and durations. Confusing them is a common mistake.

The product warranty covers the panels, inverters and battery hardware against defects. The performance warranty (common on panels) addresses gradual output degradation over time. The workmanship warranty covers the quality of the installation itself, including mounting, cabling and system integration.

• Product warranty: covers hardware faults from the manufacturer
• Performance warranty: covers degradation beyond an expected curve
• Workmanship warranty: covers the installer's build quality
• Battery warranties often reference cycles or throughput, not just years

What a good SLA includes for commercial sites

A service level agreement is where guarantees get teeth. It defines how quickly your installer or service provider responds when something goes wrong, and that response time can be the difference between a minor dip and days of lost generation on a busy facility.

For a commercial site, uptime matters. A well-written SLA sets clear response and rectification targets, names who does the work, and explains how issues are reported and escalated.

• Response times for faults and performance alerts
• Rectification targets, not just acknowledgement times
• Who performs the work and how fast they can mobilise
• Reporting channels and escalation paths
• Scope of any scheduled maintenance included

Monitoring: the evidence behind every claim

You can't enforce a guarantee you can't measure. Proper monitoring gives you the data to see when a string underperforms, an inverter drops out, or a battery isn't cycling as expected.

This is especially important where AI-driven energy arbitrage is involved. A battery that charges when power is cheap and discharges or exports when it's dear only delivers value if it's actually running the right strategy, and monitoring is how you confirm that it is. Good data also makes any warranty conversation straightforward rather than a he-said-she-said.

• Live visibility of generation, storage and export
• Alerts when performance drifts from expectations
• Historical data to support any guarantee claim
• Insight into whether arbitrage strategies are delivering

Why in-house delivery changes the equation

An SLA is only as reliable as the team standing behind it. Where installs are handed to subcontractors, accountability can get blurry when something needs fixing, and you can end up chasing multiple parties.

ATI runs an in-house team with no subcontractors, and we're CEC and SAA accredited. That means the same people who designed and built your system are responsible for its performance, from a 6.6kW setup through to megawatt-scale commercial projects. We've delivered work like the 415kW rooftop at DB Santasalo in Bulli, along with sites for Garmin, Goldschmidt, a Hunter Valley vineyard and Kingswood.

• One accountable team for design, install and service
• Accredited work that stands up to scrutiny
• Proven delivery across residential to MW-scale commercial

Questions to ask before you sign

Before committing to any commercial system, get the guarantees and SLA in writing and read them against your actual operation. What matters for a 24/7 facility is different to a weekday-only site.

If you'd like a clear picture of what performance guarantees and SLAs would suit your site, tariff and load profile, a site review is the best place to start. We can walk through the real numbers and the commitments that back them.

• How is performance measured, and against what benchmark?
• What are the response and rectification times in the SLA?
• Who actually does the service work?
• What voids each warranty, and what maintenance is required?
• How will I see whether the system is performing day to day?

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