DC/AC ratio and inverter sizing: why installers put more panels than inverter
Panel capacity divided by inverter capacity. 1.2 means 20% more panel watts than inverter watts — normal, because panels rarely hit their rating.
Panels are rated in DC watts at lab conditions; real roofs are hotter and less sunny, so panels spend most of their life well below their rating. Installers therefore pair them with a slightly smaller inverter.
A ratio around 1.1–1.3 is typical. The cost is a little “clipping” on the sunniest hours; the benefit is a cheaper inverter that runs more efficiently most of the day.
With microinverters, look at the per-panel pairing (e.g., a 430 W panel on a 290–380 W microinverter).
What this means for you: A ratio of 1.1–1.3 is a normal design choice, not a red flag. Much above 1.4, ask the installer how much energy is clipped.