Microinverters.

01How it works

A microinverter is a whole inverter, made small, fixed under a single panel. It tracks that panel's best operating point and converts its output on the spot. The cable coming down from the roof carries alternating current, ready to use.

There's no central inverter. Each panel is, in effect, a small solar system of its own, and the roof is a collection of them.

02What's different

Two things follow. Every panel is fully independent: shade, dirt or a fault on one has no effect on any other. And because conversion happens at the panel, there's no long run of high-voltage direct current through the roof space and down the wall.

As with optimisers, each panel is monitored separately.

Every panel is its own small system. The roof is a collection of them.

03Growing later

Because nothing is sized around a central inverter, adding panels later is straightforward. Each new panel brings its own microinverter and joins the others. That suits a home that wants to start small, or one where a second roof face will become available after a renovation.

04The trade

All of the electronics live on the roof, under the panels, in the heat. They're designed for it, but that's the hardest place on a house to reach, and there are as many of them as there are panels.

Each microinverter also has its own power limit. Paired with a large modern panel, it may trim a little off the very top of the best days. Over a year that's a small amount, and it's allowed for in the design.

05With a battery

The roof delivers alternating current, and a battery stores direct current, so a battery in a microinverter system has an inverter of its own and connects on the home's side. It works well. It's a separate piece of equipment, not an extension of what's on the roof.

06Which roofs

Microinverters suit the same roofs optimisers do: shaded ones, and ones made of several small faces. They particularly suit small or staged installations.

Between the two panel-level options, the choice usually comes down to whether a battery is part of the plan and how you'd like the system to grow. We install all three, so we have no reason to steer you towards one. We'll tell you plainly which your roof calls for.