First, the naming
Every solar panel produces direct current (DC). The "AC vs DC panel" question is really about where the conversion to AC happens. A DC module sends its DC down to a shared string inverter that converts the whole array at once. An AC module has a small microinverter attached to each panel, so it outputs grid-ready AC at the panel itself.
A note on the history
The distinction goes back to the 1880s "War of the Currents". Edison backed DC, which flows in one direction; Tesla and Westinghouse backed AC, whose great advantage was that transformers could easily step it up and down for efficient long-distance transmission. AC won the grid — but DC never left: it powers electronics, LEDs, EVs, batteries, and the solar cells themselves. Modern high-voltage DC (HVDC) links even carry power over long distances again.
AC modules (microinverters)
An AC module integrates a microinverter behind each panel, converting DC to AC on the spot. Because every panel is independent, the system behaves very differently from a single-string design.
- No single point of failure. If one microinverter or panel fails, only that unit drops out — the rest keep producing.
- Per-panel MPPT. Each panel runs at its own optimum, so shading or a dirty panel doesn't drag down the whole string. Mismatch losses are minimal.
- Easy to expand. The minimum system is a single module, and you can add panels later without re-engineering a string.
- Safer wiring. No high-voltage DC running across the roof, which reduces DC arc and fire risk.
- Panel-level monitoring. You can see the output of each individual panel.
The trade-offs are a higher up-front cost (you're buying many small inverters instead of one) and more electronics on the roof to maintain over the system's life.
DC modules (string inverters)
DC modules feed a single string (or hybrid) inverter. This is the long-standing mainstream design: typically cheaper per watt, with one accessible inverter to service. Its weaknesses are the mirror image of the AC module's strengths — a fault or heavy shading on one panel affects the string, and there's high-voltage DC cabling on the roof.
Crucially, DC is what batteries store. A battery charges and discharges in DC, so DC-coupled systems (string/hybrid inverter plus battery) avoid an extra AC↔DC conversion. AC-coupled storage is possible but adds conversion steps and losses.
Which is best for you?
As a rule of thumb:
- Panels only, complex roof or shading: AC modules (microinverters) are often the better fit — independence, per-panel MPPT, and safety outweigh the cost premium.
- Planning a battery now or later: a DC-coupled string/hybrid inverter is usually preferable, because the battery and panels share DC and the inverter is already sized for storage.
- Simple unshaded roof, tight budget: a string inverter is hard to beat on cost per watt.
There's no universal winner — it depends on the roof, the shading, and whether storage is on the roadmap. Solar Analytica rates inverters across residential, small-commercial, and C&I tiers; see the methodology, or browse independent scores on review.solar.