The two ways a business watches its solar
In practice there are three: the inverter maker’s app, an in-house person or team checking that app, and an independent monitor that reads every string across every brand. The first two share the same blind spot — they depend on the vendor’s own number.
That’s the crux. “In-house monitoring” usually means someone on your team logging into the inverter app. It’s only as good as what that app chooses to show — which is the plant total, not the health of each string.
The conflict of interest
An inverter maker’s platform has no incentive to highlight that its own hardware is derating, or that a string on its input has failed. It will tell you the system is “producing”. An independent monitor has the opposite incentive: its entire job is to find what’s wrong, whoever made the equipment.
That independence is worth the most exactly when the stakes are highest — a warranty claim, an underperformance dispute, or a decision about whether a system is worth expanding. Those need honest, third-party numbers, not the vendor’s reassurance.
Coverage and cost, honestly
A pure in-house approach doesn’t scale. One person can watch a couple of sites on a couple of apps; give them ten sites across four inverter brands and the faults start slipping through. Independent, multi-brand monitoring puts every site and every string on one screen, so the same team covers far more without missing things.
The cost trade is not “pay for monitoring vs. get it free”. In-house-only monitoring has a real cost too — the output you lose to faults nobody catches. On the systems we monitor, that’s been the difference between 4.8 and 2.3 kWh/kWp/day across sites.
| In-house (vendor app) | Independent monitoring | |
|---|---|---|
| Resolution | Plant total | Every string |
| Conflict of interest | Vendor grades itself | None — finds every fault |
| Multi-brand | One app per brand | Every brand, one screen |
| Scales to many sites | Poorly | Yes |
| Warranty-claim proof | Weak | Independent evidence |
When each makes sense
A single small site with one inverter brand and someone genuinely watching it daily can get by in-house. The moment you have multiple sites, mixed brands, or real money riding on performance, independent monitoring stops being optional.
The best answer for most C&I owners is not either/or. It’s independent, string-level data as the source of truth — feeding whoever acts on it. That can be your own O&M team, scaled by the monitoring, or ours as a full service.
How we do it
Solar Performance Cloud is the independent layer: multi-brand, string-level, engineer-verified, running on the equipment you already own. WattEY adds the whole-site energy picture across grid, generator and solar. Together they give an owner — or an in-house team — the honest numbers to act on, instead of a vendor’s green light.
