What to look at.

01Right now

The first screen in most apps is a picture of power moving: from the roof to the home, into or out of the battery, to or from the grid. It answers one question, which is where your electricity is coming from at this moment.

It's the screen to open before you turn something big on. If the roof is making four kilowatts and the house is using one, that's a good time for the dishwasher.

02The shape of the day

The day's chart is the most informative thing in the app. A clear day draws a smooth bell curve, rising from sunrise, peaking around midday and falling to sunset. Passing cloud cuts notches in it. A grey day flattens it into a low, ragged hump.

Look at the top of the curve on a bright day. If it's flat, as though someone had sliced the peak off, your system is reaching a limit: the inverter's capacity or your export limit. A little of that on the best days is normal and usually deliberate.

A clear day draws a clean curve. Learn its shape and you'll spot anything unusual at a glance.

03Above and below the line

Many apps draw generation above a line and consumption below it, each split by colour. Above: how much of what you made went to the home, to the battery and to the grid. Below: how much of what you used came from the roof, from the battery and from the grid.

The share of your use that didn't come from the grid is the number that tracks your saving most closely. Watching it is how you learn what your household's habits are worth.

04The battery's day

If you have a battery, two times of day tell you most of what you need. When does it fill? When does it run out?

Full by eleven and empty by ten at night says the battery is small for your evenings. Never quite full in winter says the roof has little to spare at that time of year, which is expected. Still half full at sunrise, all year, says you have more than you use.

05Month against month

Totals are for comparing, and the fair comparison is with the same month a year ago, not with last month. October will always beat June. What you're looking for is whether this October looks like last October.

06When to get in touch

A few things are worth a call. No generation at all on a sunny day. A system that shows as offline for more than a day or so. An error or fault message. Or, if you have panel-level monitoring, one panel sitting well below its neighbours day after day.

Most of the time the cause is small: a tripped switch, or the home's internet connection. It's still worth asking.