14.4 The bar: UL 3700 whole-system certification, and why you still can't buy one

The bar to entry is higher than it looks. California doesn't want the panel and inverter certified separately — it wants the whole system (panels + cabling + racking + inverter) certified as one "plug-in PV system" under UL 3700, a standard only published in December 2025.

Contrast Utah (usable since 2025): Utah only requires each component to be UL-listed, so products have been on sale there for a while; California wants whole-system certification, and so far only a few microinverters have it — most complete kits are still in testing. So when the 2027 law takes effect it's not even certain compliant products will exist; the current expectation is they won't become common until spring 2027 or later. If you want one, you'll have to wait. It also means that even once a company earns certification, the price is unlikely to be cheap, and payback has to be modeled case by case.